8751 lines
293 KiB
C
8751 lines
293 KiB
C
/************** Begin file btree.c *******************************************/
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/*
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** 2004 April 6
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**
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** The author disclaims copyright to this source code. In place of
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** a legal notice, here is a blessing:
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**
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** May you do good and not evil.
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** May you find forgiveness for yourself and forgive others.
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** May you share freely, never taking more than you give.
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**
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*************************************************************************
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** This file implements a external (disk-based) database using BTrees.
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** See the header comment on "btreeInt.h" for additional information.
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** Including a description of file format and an overview of operation.
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*/
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/*
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** The header string that appears at the beginning of every
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** SQLite database.
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*/
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static const char zMagicHeader[] = SQLITE_FILE_HEADER;
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int g_expect_full_pointermap = 0;
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#define PTRMAP_LAZYFREE 20
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/*
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** Set this global variable to 1 to enable tracing using the TRACE
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** macro.
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*/
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#if 0
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int sqlite3BtreeTrace=1; /* True to enable tracing */
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# define TRACE(X) if(sqlite3BtreeTrace){printf X;fflush(stdout);}
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#else
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# define TRACE(X)
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#endif
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/*
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** Extract a 2-byte big-endian integer from an array of unsigned bytes.
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** But if the value is zero, make it 65536.
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**
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** This routine is used to extract the "offset to cell content area" value
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** from the header of a btree page. If the page size is 65536 and the page
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** is empty, the offset should be 65536, but the 2-byte value stores zero.
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** This routine makes the necessary adjustment to 65536.
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*/
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#define get2byteNotZero(X) (((((int)get2byte(X))-1)&0xffff)+1)
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#ifndef SQLITE_OMIT_SHARED_CACHE
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/*
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** A list of BtShared objects that are eligible for participation
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** in shared cache. This variable has file scope during normal builds,
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** but the test harness needs to access it so we make it global for
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** test builds.
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**
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** Access to this variable is protected by SQLITE_MUTEX_STATIC_MASTER.
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*/
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#ifdef SQLITE_TEST
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SQLITE_PRIVATE BtShared *SQLITE_WSD sqlite3SharedCacheList = 0;
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#else
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static BtShared *SQLITE_WSD sqlite3SharedCacheList = 0;
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#endif
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#endif /* SQLITE_OMIT_SHARED_CACHE */
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#ifndef SQLITE_OMIT_SHARED_CACHE
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/*
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** Enable or disable the shared pager and schema features.
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**
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** This routine has no effect on existing database connections.
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** The shared cache setting effects only future calls to
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** sqlite3_open(), sqlite3_open16(), or sqlite3_open_v2().
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*/
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SQLITE_API int sqlite3_enable_shared_cache(int enable){
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sqlite3GlobalConfig.sharedCacheEnabled = enable;
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return SQLITE_OK;
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}
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#endif
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#ifdef SQLITE_OMIT_SHARED_CACHE
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/*
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** The functions querySharedCacheTableLock(), setSharedCacheTableLock(),
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** and clearAllSharedCacheTableLocks()
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** manipulate entries in the BtShared.pLock linked list used to store
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** shared-cache table level locks. If the library is compiled with the
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** shared-cache feature disabled, then there is only ever one user
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** of each BtShared structure and so this locking is not necessary.
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** So define the lock related functions as no-ops.
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*/
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#define querySharedCacheTableLock(a,b,c) SQLITE_OK
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#define setSharedCacheTableLock(a,b,c) SQLITE_OK
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#define clearAllSharedCacheTableLocks(a)
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#define downgradeAllSharedCacheTableLocks(a)
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#define hasSharedCacheTableLock(a,b,c,d) 1
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#define hasReadConflicts(a, b) 0
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#endif
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#ifndef SQLITE_OMIT_SHARED_CACHE
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#ifdef SQLITE_DEBUG
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/*
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**** This function is only used as part of an assert() statement. ***
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**
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** Check to see if pBtree holds the required locks to read or write to the
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** table with root page iRoot. Return 1 if it does and 0 if not.
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**
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** For example, when writing to a table with root-page iRoot via
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** Btree connection pBtree:
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**
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** assert( hasSharedCacheTableLock(pBtree, iRoot, 0, WRITE_LOCK) );
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**
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** When writing to an index that resides in a sharable database, the
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** caller should have first obtained a lock specifying the root page of
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** the corresponding table. This makes things a bit more complicated,
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** as this module treats each table as a separate structure. To determine
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** the table corresponding to the index being written, this
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** function has to search through the database schema.
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**
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** Instead of a lock on the table/index rooted at page iRoot, the caller may
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** hold a write-lock on the schema table (root page 1). This is also
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** acceptable.
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*/
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static int hasSharedCacheTableLock(
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Btree *pBtree, /* Handle that must hold lock */
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Pgno iRoot, /* Root page of b-tree */
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int isIndex, /* True if iRoot is the root of an index b-tree */
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int eLockType /* Required lock type (READ_LOCK or WRITE_LOCK) */
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){
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Schema *pSchema = (Schema *)pBtree->pBt->pSchema;
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Pgno iTab = 0;
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BtLock *pLock;
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/* If this database is not shareable, or if the client is reading
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** and has the read-uncommitted flag set, then no lock is required.
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** Return true immediately.
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*/
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if( (pBtree->sharable==0)
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|| (eLockType==READ_LOCK && (pBtree->db->flags & SQLITE_ReadUncommitted))
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){
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return 1;
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}
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/* If the client is reading or writing an index and the schema is
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** not loaded, then it is too difficult to actually check to see if
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** the correct locks are held. So do not bother - just return true.
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** This case does not come up very often anyhow.
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*/
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if( isIndex && (!pSchema || (pSchema->flags&DB_SchemaLoaded)==0) ){
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return 1;
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}
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/* Figure out the root-page that the lock should be held on. For table
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** b-trees, this is just the root page of the b-tree being read or
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** written. For index b-trees, it is the root page of the associated
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** table. */
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if( isIndex ){
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HashElem *p;
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for(p=sqliteHashFirst(&pSchema->idxHash); p; p=sqliteHashNext(p)){
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Index *pIdx = (Index *)sqliteHashData(p);
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if( pIdx->tnum==(int)iRoot ){
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iTab = pIdx->pTable->tnum;
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}
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}
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}else{
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iTab = iRoot;
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}
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/* Search for the required lock. Either a write-lock on root-page iTab, a
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** write-lock on the schema table, or (if the client is reading) a
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** read-lock on iTab will suffice. Return 1 if any of these are found. */
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for(pLock=pBtree->pBt->pLock; pLock; pLock=pLock->pNext){
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if( pLock->pBtree==pBtree
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&& (pLock->iTable==iTab || (pLock->eLock==WRITE_LOCK && pLock->iTable==1))
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&& pLock->eLock>=eLockType
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){
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return 1;
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}
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}
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/* Failed to find the required lock. */
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return 0;
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}
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#endif /* SQLITE_DEBUG */
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#ifdef SQLITE_DEBUG
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/*
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**** This function may be used as part of assert() statements only. ****
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**
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** Return true if it would be illegal for pBtree to write into the
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** table or index rooted at iRoot because other shared connections are
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** simultaneously reading that same table or index.
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**
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** It is illegal for pBtree to write if some other Btree object that
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** shares the same BtShared object is currently reading or writing
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** the iRoot table. Except, if the other Btree object has the
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** read-uncommitted flag set, then it is OK for the other object to
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** have a read cursor.
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**
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** For example, before writing to any part of the table or index
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** rooted at page iRoot, one should call:
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**
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** assert( !hasReadConflicts(pBtree, iRoot) );
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*/
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static int hasReadConflicts(Btree *pBtree, Pgno iRoot){
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BtCursor *p;
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for(p=pBtree->pBt->pCursor; p; p=p->pNext){
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if( p->pgnoRoot==iRoot
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&& p->pBtree!=pBtree
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&& 0==(p->pBtree->db->flags & SQLITE_ReadUncommitted)
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){
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return 1;
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}
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}
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return 0;
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}
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#endif /* #ifdef SQLITE_DEBUG */
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/*
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** Query to see if Btree handle p may obtain a lock of type eLock
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** (READ_LOCK or WRITE_LOCK) on the table with root-page iTab. Return
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** SQLITE_OK if the lock may be obtained (by calling
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** setSharedCacheTableLock()), or SQLITE_LOCKED if not.
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*/
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static int querySharedCacheTableLock(Btree *p, Pgno iTab, u8 eLock){
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BtShared *pBt = p->pBt;
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BtLock *pIter;
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assert( sqlite3BtreeHoldsMutex(p) );
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assert( eLock==READ_LOCK || eLock==WRITE_LOCK );
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assert( p->db!=0 );
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assert( !(p->db->flags&SQLITE_ReadUncommitted)||eLock==WRITE_LOCK||iTab==1 );
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/* If requesting a write-lock, then the Btree must have an open write
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** transaction on this file. And, obviously, for this to be so there
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** must be an open write transaction on the file itself.
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*/
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assert( eLock==READ_LOCK || (p==pBt->pWriter && p->inTrans==TRANS_WRITE) );
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assert( eLock==READ_LOCK || pBt->inTransaction==TRANS_WRITE );
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/* This routine is a no-op if the shared-cache is not enabled */
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if( !p->sharable ){
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return SQLITE_OK;
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}
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/* If some other connection is holding an exclusive lock, the
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** requested lock may not be obtained.
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*/
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if( pBt->pWriter!=p && pBt->isExclusive ){
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sqlite3ConnectionBlocked(p->db, pBt->pWriter->db);
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return SQLITE_LOCKED_SHAREDCACHE;
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}
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for(pIter=pBt->pLock; pIter; pIter=pIter->pNext){
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/* The condition (pIter->eLock!=eLock) in the following if(...)
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** statement is a simplification of:
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**
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** (eLock==WRITE_LOCK || pIter->eLock==WRITE_LOCK)
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**
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** since we know that if eLock==WRITE_LOCK, then no other connection
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** may hold a WRITE_LOCK on any table in this file (since there can
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** only be a single writer).
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*/
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assert( pIter->eLock==READ_LOCK || pIter->eLock==WRITE_LOCK );
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assert( eLock==READ_LOCK || pIter->pBtree==p || pIter->eLock==READ_LOCK);
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if( pIter->pBtree!=p && pIter->iTable==iTab && pIter->eLock!=eLock ){
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sqlite3ConnectionBlocked(p->db, pIter->pBtree->db);
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if( eLock==WRITE_LOCK ){
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assert( p==pBt->pWriter );
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pBt->isPending = 1;
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}
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return SQLITE_LOCKED_SHAREDCACHE;
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}
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}
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return SQLITE_OK;
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}
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#endif /* !SQLITE_OMIT_SHARED_CACHE */
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#ifndef SQLITE_OMIT_SHARED_CACHE
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/*
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** Add a lock on the table with root-page iTable to the shared-btree used
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** by Btree handle p. Parameter eLock must be either READ_LOCK or
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** WRITE_LOCK.
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**
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** This function assumes the following:
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**
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** (a) The specified Btree object p is connected to a sharable
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** database (one with the BtShared.sharable flag set), and
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**
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** (b) No other Btree objects hold a lock that conflicts
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** with the requested lock (i.e. querySharedCacheTableLock() has
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** already been called and returned SQLITE_OK).
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**
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** SQLITE_OK is returned if the lock is added successfully. SQLITE_NOMEM
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** is returned if a malloc attempt fails.
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*/
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static int setSharedCacheTableLock(Btree *p, Pgno iTable, u8 eLock){
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BtShared *pBt = p->pBt;
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BtLock *pLock = 0;
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BtLock *pIter;
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assert( sqlite3BtreeHoldsMutex(p) );
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assert( eLock==READ_LOCK || eLock==WRITE_LOCK );
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assert( p->db!=0 );
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/* A connection with the read-uncommitted flag set will never try to
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** obtain a read-lock using this function. The only read-lock obtained
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** by a connection in read-uncommitted mode is on the sqlite_master
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** table, and that lock is obtained in BtreeBeginTrans(). */
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assert( 0==(p->db->flags&SQLITE_ReadUncommitted) || eLock==WRITE_LOCK );
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/* This function should only be called on a sharable b-tree after it
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** has been determined that no other b-tree holds a conflicting lock. */
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assert( p->sharable );
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assert( SQLITE_OK==querySharedCacheTableLock(p, iTable, eLock) );
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/* First search the list for an existing lock on this table. */
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for(pIter=pBt->pLock; pIter; pIter=pIter->pNext){
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if( pIter->iTable==iTable && pIter->pBtree==p ){
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pLock = pIter;
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break;
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}
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}
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/* If the above search did not find a BtLock struct associating Btree p
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** with table iTable, allocate one and link it into the list.
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*/
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if( !pLock ){
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pLock = (BtLock *)sqlite3MallocZero(sizeof(BtLock));
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if( !pLock ){
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return SQLITE_NOMEM;
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}
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pLock->iTable = iTable;
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pLock->pBtree = p;
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pLock->pNext = pBt->pLock;
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pBt->pLock = pLock;
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}
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/* Set the BtLock.eLock variable to the maximum of the current lock
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** and the requested lock. This means if a write-lock was already held
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** and a read-lock requested, we don't incorrectly downgrade the lock.
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*/
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assert( WRITE_LOCK>READ_LOCK );
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if( eLock>pLock->eLock ){
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pLock->eLock = eLock;
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}
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return SQLITE_OK;
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}
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#endif /* !SQLITE_OMIT_SHARED_CACHE */
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#ifndef SQLITE_OMIT_SHARED_CACHE
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/*
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** Release all the table locks (locks obtained via calls to
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** the setSharedCacheTableLock() procedure) held by Btree object p.
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**
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** This function assumes that Btree p has an open read or write
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** transaction. If it does not, then the BtShared.isPending variable
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** may be incorrectly cleared.
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*/
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static void clearAllSharedCacheTableLocks(Btree *p){
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BtShared *pBt = p->pBt;
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BtLock **ppIter = &pBt->pLock;
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assert( sqlite3BtreeHoldsMutex(p) );
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assert( p->sharable || 0==*ppIter );
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assert( p->inTrans>0 );
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while( *ppIter ){
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BtLock *pLock = *ppIter;
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assert( pBt->isExclusive==0 || pBt->pWriter==pLock->pBtree );
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assert( pLock->pBtree->inTrans>=pLock->eLock );
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if( pLock->pBtree==p ){
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*ppIter = pLock->pNext;
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assert( pLock->iTable!=1 || pLock==&p->lock );
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if( pLock->iTable!=1 ){
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sqlite3_free(pLock);
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}
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}else{
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ppIter = &pLock->pNext;
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}
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}
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assert( pBt->isPending==0 || pBt->pWriter );
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if( pBt->pWriter==p ){
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pBt->pWriter = 0;
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pBt->isExclusive = 0;
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pBt->isPending = 0;
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}else if( pBt->nTransaction==2 ){
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/* This function is called when Btree p is concluding its
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** transaction. If there currently exists a writer, and p is not
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** that writer, then the number of locks held by connections other
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** than the writer must be about to drop to zero. In this case
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** set the isPending flag to 0.
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**
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** If there is not currently a writer, then BtShared.isPending must
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** be zero already. So this next line is harmless in that case.
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*/
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pBt->isPending = 0;
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}
|
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}
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/*
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** This function changes all write-locks held by Btree p into read-locks.
|
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*/
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static void downgradeAllSharedCacheTableLocks(Btree *p){
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BtShared *pBt = p->pBt;
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if( pBt->pWriter==p ){
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BtLock *pLock;
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pBt->pWriter = 0;
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pBt->isExclusive = 0;
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pBt->isPending = 0;
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for(pLock=pBt->pLock; pLock; pLock=pLock->pNext){
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assert( pLock->eLock==READ_LOCK || pLock->pBtree==p );
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pLock->eLock = READ_LOCK;
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}
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}
|
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}
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#endif /* SQLITE_OMIT_SHARED_CACHE */
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static void releasePage(MemPage *pPage); /* Forward reference */
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/*
|
|
***** This routine is used inside of assert() only ****
|
|
**
|
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** Verify that the cursor holds the mutex on its BtShared
|
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*/
|
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#ifdef SQLITE_DEBUG
|
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static int cursorHoldsMutex(BtCursor *p){
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return sqlite3_mutex_held(p->pBt->mutex);
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}
|
|
#endif
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|
|
#ifndef SQLITE_OMIT_INCRBLOB
|
|
/*
|
|
** Invalidate the overflow page-list cache for cursor pCur, if any.
|
|
*/
|
|
static void invalidateOverflowCache(BtCursor *pCur){
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assert( cursorHoldsMutex(pCur) );
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sqlite3_free(pCur->aOverflow);
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pCur->aOverflow = 0;
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}
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/*
|
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** Invalidate the overflow page-list cache for all cursors opened
|
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** on the shared btree structure pBt.
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*/
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static void invalidateAllOverflowCache(BtShared *pBt){
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BtCursor *p;
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assert( sqlite3_mutex_held(pBt->mutex) );
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for(p=pBt->pCursor; p; p=p->pNext){
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invalidateOverflowCache(p);
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}
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}
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/*
|
|
** This function is called before modifying the contents of a table
|
|
** to invalidate any incrblob cursors that are open on the
|
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** row or one of the rows being modified.
|
|
**
|
|
** If argument isClearTable is true, then the entire contents of the
|
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** table is about to be deleted. In this case invalidate all incrblob
|
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** cursors open on any row within the table with root-page pgnoRoot.
|
|
**
|
|
** Otherwise, if argument isClearTable is false, then the row with
|
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** rowid iRow is being replaced or deleted. In this case invalidate
|
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** only those incrblob cursors open on that specific row.
|
|
*/
|
|
static void invalidateIncrblobCursors(
|
|
Btree *pBtree, /* The database file to check */
|
|
i64 iRow, /* The rowid that might be changing */
|
|
int isClearTable /* True if all rows are being deleted */
|
|
){
|
|
BtCursor *p;
|
|
BtShared *pBt = pBtree->pBt;
|
|
assert( sqlite3BtreeHoldsMutex(pBtree) );
|
|
for(p=pBt->pCursor; p; p=p->pNext){
|
|
if( p->isIncrblobHandle && (isClearTable || p->info.nKey==iRow) ){
|
|
p->eState = CURSOR_INVALID;
|
|
}
|
|
}
|
|
}
|
|
|
|
#else
|
|
/* Stub functions when INCRBLOB is omitted */
|
|
#define invalidateOverflowCache(x)
|
|
#define invalidateAllOverflowCache(x)
|
|
#define invalidateIncrblobCursors(x,y,z)
|
|
#endif /* SQLITE_OMIT_INCRBLOB */
|
|
|
|
/*
|
|
** Set bit pgno of the BtShared.pHasContent bitvec. This is called
|
|
** when a page that previously contained data becomes a free-list leaf
|
|
** page.
|
|
**
|
|
** The BtShared.pHasContent bitvec exists to work around an obscure
|
|
** bug caused by the interaction of two useful IO optimizations surrounding
|
|
** free-list leaf pages:
|
|
**
|
|
** 1) When all data is deleted from a page and the page becomes
|
|
** a free-list leaf page, the page is not written to the database
|
|
** (as free-list leaf pages contain no meaningful data). Sometimes
|
|
** such a page is not even journalled (as it will not be modified,
|
|
** why bother journalling it?).
|
|
**
|
|
** 2) When a free-list leaf page is reused, its content is not read
|
|
** from the database or written to the journal file (why should it
|
|
** be, if it is not at all meaningful?).
|
|
**
|
|
** By themselves, these optimizations work fine and provide a handy
|
|
** performance boost to bulk delete or insert operations. However, if
|
|
** a page is moved to the free-list and then reused within the same
|
|
** transaction, a problem comes up. If the page is not journalled when
|
|
** it is moved to the free-list and it is also not journalled when it
|
|
** is extracted from the free-list and reused, then the original data
|
|
** may be lost. In the event of a rollback, it may not be possible
|
|
** to restore the database to its original configuration.
|
|
**
|
|
** The solution is the BtShared.pHasContent bitvec. Whenever a page is
|
|
** moved to become a free-list leaf page, the corresponding bit is
|
|
** set in the bitvec. Whenever a leaf page is extracted from the free-list,
|
|
** optimization 2 above is omitted if the corresponding bit is already
|
|
** set in BtShared.pHasContent. The contents of the bitvec are cleared
|
|
** at the end of every transaction.
|
|
*/
|
|
static int btreeSetHasContent(BtShared *pBt, Pgno pgno){
|
|
int rc = SQLITE_OK;
|
|
if( !pBt->pHasContent ){
|
|
assert( pgno<=pBt->nPage );
|
|
pBt->pHasContent = sqlite3BitvecCreate(pBt->nPage);
|
|
if( !pBt->pHasContent ){
|
|
rc = SQLITE_NOMEM;
|
|
}
|
|
}
|
|
if( rc==SQLITE_OK && pgno<=sqlite3BitvecSize(pBt->pHasContent) ){
|
|
rc = sqlite3BitvecSet(pBt->pHasContent, pgno);
|
|
}
|
|
return rc;
|
|
}
|
|
|
|
/*
|
|
** Query the BtShared.pHasContent vector.
|
|
**
|
|
** This function is called when a free-list leaf page is removed from the
|
|
** free-list for reuse. It returns false if it is safe to retrieve the
|
|
** page from the pager layer with the 'no-content' flag set. True otherwise.
|
|
*/
|
|
static int btreeGetHasContent(BtShared *pBt, Pgno pgno){
|
|
Bitvec *p = pBt->pHasContent;
|
|
return (p && (pgno>sqlite3BitvecSize(p) || sqlite3BitvecTest(p, pgno)));
|
|
}
|
|
|
|
/*
|
|
** Clear (destroy) the BtShared.pHasContent bitvec. This should be
|
|
** invoked at the conclusion of each write-transaction.
|
|
*/
|
|
static void btreeClearHasContent(BtShared *pBt){
|
|
sqlite3BitvecDestroy(pBt->pHasContent);
|
|
pBt->pHasContent = 0;
|
|
}
|
|
|
|
/*
|
|
** Save the current cursor position in the variables BtCursor.nKey
|
|
** and BtCursor.pKey. The cursor's state is set to CURSOR_REQUIRESEEK.
|
|
**
|
|
** The caller must ensure that the cursor is valid (has eState==CURSOR_VALID)
|
|
** prior to calling this routine.
|
|
*/
|
|
static int saveCursorPosition(BtCursor *pCur){
|
|
int rc;
|
|
|
|
assert( CURSOR_VALID==pCur->eState );
|
|
assert( 0==pCur->pKey );
|
|
assert( cursorHoldsMutex(pCur) );
|
|
|
|
rc = sqlite3BtreeKeySize(pCur, &pCur->nKey);
|
|
assert( rc==SQLITE_OK ); /* KeySize() cannot fail */
|
|
|
|
/* If this is an intKey table, then the above call to BtreeKeySize()
|
|
** stores the integer key in pCur->nKey. In this case this value is
|
|
** all that is required. Otherwise, if pCur is not open on an intKey
|
|
** table, then malloc space for and store the pCur->nKey bytes of key
|
|
** data.
|
|
*/
|
|
if( 0==pCur->apPage[0]->intKey ){
|
|
void *pKey = sqlite3Malloc( (int)pCur->nKey );
|
|
if( pKey ){
|
|
rc = sqlite3BtreeKey(pCur, 0, (int)pCur->nKey, pKey);
|
|
if( rc==SQLITE_OK ){
|
|
pCur->pKey = pKey;
|
|
}else{
|
|
sqlite3_free(pKey);
|
|
}
|
|
}else{
|
|
rc = SQLITE_NOMEM;
|
|
}
|
|
}
|
|
assert( !pCur->apPage[0]->intKey || !pCur->pKey );
|
|
|
|
if( rc==SQLITE_OK ){
|
|
int i;
|
|
for(i=0; i<=pCur->iPage; i++){
|
|
releasePage(pCur->apPage[i]);
|
|
pCur->apPage[i] = 0;
|
|
}
|
|
pCur->iPage = -1;
|
|
pCur->eState = CURSOR_REQUIRESEEK;
|
|
}
|
|
|
|
invalidateOverflowCache(pCur);
|
|
return rc;
|
|
}
|
|
|
|
/*
|
|
** Save the positions of all cursors (except pExcept) that are open on
|
|
** the table with root-page iRoot. Usually, this is called just before cursor
|
|
** pExcept is used to modify the table (BtreeDelete() or BtreeInsert()).
|
|
*/
|
|
static int saveAllCursors(BtShared *pBt, Pgno iRoot, BtCursor *pExcept){
|
|
BtCursor *p;
|
|
assert( sqlite3_mutex_held(pBt->mutex) );
|
|
assert( pExcept==0 || pExcept->pBt==pBt );
|
|
for(p=pBt->pCursor; p; p=p->pNext){
|
|
if( p!=pExcept && (0==iRoot || p->pgnoRoot==iRoot) &&
|
|
p->eState==CURSOR_VALID ){
|
|
int rc = saveCursorPosition(p);
|
|
if( SQLITE_OK!=rc ){
|
|
return rc;
|
|
}
|
|
}
|
|
}
|
|
return SQLITE_OK;
|
|
}
|
|
|
|
/*
|
|
** Clear the current cursor position.
|
|
*/
|
|
SQLITE_PRIVATE void sqlite3BtreeClearCursor(BtCursor *pCur){
|
|
assert( cursorHoldsMutex(pCur) );
|
|
sqlite3_free(pCur->pKey);
|
|
pCur->pKey = 0;
|
|
pCur->eState = CURSOR_INVALID;
|
|
}
|
|
|
|
/*
|
|
** In this version of BtreeMoveto, pKey is a packed index record
|
|
** such as is generated by the OP_MakeRecord opcode. Unpack the
|
|
** record and then call BtreeMovetoUnpacked() to do the work.
|
|
*/
|
|
static int btreeMoveto(
|
|
BtCursor *pCur, /* Cursor open on the btree to be searched */
|
|
const void *pKey, /* Packed key if the btree is an index */
|
|
i64 nKey, /* Integer key for tables. Size of pKey for indices */
|
|
int bias, /* Bias search to the high end */
|
|
int *pRes /* Write search results here */
|
|
){
|
|
int rc; /* Status code */
|
|
UnpackedRecord *pIdxKey; /* Unpacked index key */
|
|
char aSpace[150]; /* Temp space for pIdxKey - to avoid a malloc */
|
|
|
|
if( pKey ){
|
|
assert( nKey==(i64)(int)nKey );
|
|
pIdxKey = sqlite3VdbeRecordUnpack(pCur->pKeyInfo, (int)nKey, pKey,
|
|
aSpace, sizeof(aSpace));
|
|
if( pIdxKey==0 ) return SQLITE_NOMEM;
|
|
}else{
|
|
pIdxKey = 0;
|
|
}
|
|
rc = sqlite3BtreeMovetoUnpacked(pCur, pIdxKey, nKey, bias, pRes);
|
|
if( pKey ){
|
|
sqlite3VdbeDeleteUnpackedRecord(pIdxKey);
|
|
}
|
|
return rc;
|
|
}
|
|
|
|
/*
|
|
** Restore the cursor to the position it was in (or as close to as possible)
|
|
** when saveCursorPosition() was called. Note that this call deletes the
|
|
** saved position info stored by saveCursorPosition(), so there can be
|
|
** at most one effective restoreCursorPosition() call after each
|
|
** saveCursorPosition().
|
|
*/
|
|
static int btreeRestoreCursorPosition(BtCursor *pCur){
|
|
int rc;
|
|
assert( cursorHoldsMutex(pCur) );
|
|
assert( pCur->eState>=CURSOR_REQUIRESEEK );
|
|
if( pCur->eState==CURSOR_FAULT ){
|
|
return pCur->skipNext;
|
|
}
|
|
pCur->eState = CURSOR_INVALID;
|
|
rc = btreeMoveto(pCur, pCur->pKey, pCur->nKey, 0, &pCur->skipNext);
|
|
if( rc==SQLITE_OK ){
|
|
sqlite3_free(pCur->pKey);
|
|
pCur->pKey = 0;
|
|
assert( pCur->eState==CURSOR_VALID || pCur->eState==CURSOR_INVALID );
|
|
}
|
|
return rc;
|
|
}
|
|
|
|
#define restoreCursorPosition(p) \
|
|
(p->eState>=CURSOR_REQUIRESEEK ? \
|
|
btreeRestoreCursorPosition(p) : \
|
|
SQLITE_OK)
|
|
|
|
/*
|
|
** Determine whether or not a cursor has moved from the position it
|
|
** was last placed at. Cursors can move when the row they are pointing
|
|
** at is deleted out from under them.
|
|
**
|
|
** This routine returns an error code if something goes wrong. The
|
|
** integer *pHasMoved is set to one if the cursor has moved and 0 if not.
|
|
*/
|
|
SQLITE_PRIVATE int sqlite3BtreeCursorHasMoved(BtCursor *pCur, int *pHasMoved){
|
|
int rc;
|
|
|
|
rc = restoreCursorPosition(pCur);
|
|
if( rc ){
|
|
*pHasMoved = 1;
|
|
return rc;
|
|
}
|
|
if( pCur->eState!=CURSOR_VALID || pCur->skipNext!=0 ){
|
|
*pHasMoved = 1;
|
|
}else{
|
|
*pHasMoved = 0;
|
|
}
|
|
return SQLITE_OK;
|
|
}
|
|
|
|
#ifndef SQLITE_OMIT_AUTOVACUUM
|
|
/*
|
|
** Given a page number of a regular database page, return the page
|
|
** number for the pointer-map page that contains the entry for the
|
|
** input page number.
|
|
**
|
|
** Return 0 (not a valid page) for pgno==1 since there is
|
|
** no pointer map associated with page 1. The integrity_check logic
|
|
** requires that ptrmapPageno(*,1)!=1.
|
|
*/
|
|
SQLITE_PRIVATE Pgno ptrmapPageno(BtShared *pBt, Pgno pgno){
|
|
int nPagesPerMapPage;
|
|
Pgno iPtrMap, ret;
|
|
assert( sqlite3_mutex_held(pBt->mutex) );
|
|
if( pgno<2 ) return 0;
|
|
nPagesPerMapPage = (pBt->usableSize/5)+1;
|
|
iPtrMap = (pgno-2)/nPagesPerMapPage;
|
|
ret = (iPtrMap*nPagesPerMapPage) + 2;
|
|
if( ret==PENDING_BYTE_PAGE(pBt) ){
|
|
ret++;
|
|
}
|
|
return ret;
|
|
}
|
|
|
|
/*
|
|
** Write an entry into the pointer map.
|
|
**
|
|
** This routine updates the pointer map entry for page number 'key'
|
|
** so that it maps to type 'eType' and parent page number 'pgno'.
|
|
**
|
|
** If *pRC is initially non-zero (non-SQLITE_OK) then this routine is
|
|
** a no-op. If an error occurs, the appropriate error code is written
|
|
** into *pRC.
|
|
*/
|
|
static void ptrmapPut(BtShared *pBt, Pgno key, u8 eType, Pgno parent, int *pRC){
|
|
DbPage *pDbPage; /* The pointer map page */
|
|
u8 *pPtrmap; /* The pointer map data */
|
|
Pgno iPtrmap; /* The pointer map page number */
|
|
int offset; /* Offset in pointer map page */
|
|
int rc; /* Return code from subfunctions */
|
|
|
|
if( *pRC ) return;
|
|
|
|
assert( sqlite3_mutex_held(pBt->mutex) );
|
|
/* The master-journal page number must never be used as a pointer map page */
|
|
assert( 0==PTRMAP_ISPAGE(pBt, PENDING_BYTE_PAGE(pBt)) );
|
|
|
|
assert( pBt->autoVacuum );
|
|
if( key==0 ){
|
|
*pRC = SQLITE_CORRUPT_BKPT;
|
|
return;
|
|
}
|
|
iPtrmap = PTRMAP_PAGENO(pBt, key);
|
|
rc = sqlite3PagerGet(pBt->pPager, iPtrmap, &pDbPage);
|
|
if( rc!=SQLITE_OK ){
|
|
*pRC = rc;
|
|
return;
|
|
}
|
|
offset = PTRMAP_PTROFFSET(iPtrmap, key);
|
|
if( offset<0 ){
|
|
*pRC = SQLITE_CORRUPT_BKPT;
|
|
goto ptrmap_exit;
|
|
}
|
|
pPtrmap = (u8 *)sqlite3PagerGetData(pDbPage);
|
|
|
|
if( eType!=pPtrmap[offset] || get4byte(&pPtrmap[offset+1])!=parent ){
|
|
TRACE(("PTRMAP_UPDATE: %d->(%d,%d)\n", key, eType, parent));
|
|
*pRC= rc = sqlite3PagerWrite(pDbPage);
|
|
if( rc==SQLITE_OK ){
|
|
pPtrmap[offset] = eType;
|
|
put4byte(&pPtrmap[offset+1], parent);
|
|
}
|
|
}
|
|
|
|
ptrmap_exit:
|
|
sqlite3PagerUnref(pDbPage);
|
|
}
|
|
|
|
/*
|
|
** Read an entry from the pointer map.
|
|
**
|
|
** This routine retrieves the pointer map entry for page 'key', writing
|
|
** the type and parent page number to *pEType and *pPgno respectively.
|
|
** An error code is returned if something goes wrong, otherwise SQLITE_OK.
|
|
*/
|
|
static int ptrmapGet(BtShared *pBt, Pgno key, u8 *pEType, Pgno *pPgno){
|
|
DbPage *pDbPage; /* The pointer map page */
|
|
int iPtrmap; /* Pointer map page index */
|
|
u8 *pPtrmap; /* Pointer map page data */
|
|
int offset; /* Offset of entry in pointer map */
|
|
int rc;
|
|
|
|
assert( sqlite3_mutex_held(pBt->mutex) );
|
|
|
|
iPtrmap = PTRMAP_PAGENO(pBt, key);
|
|
rc = sqlite3PagerGet(pBt->pPager, iPtrmap, &pDbPage);
|
|
if( rc!=0 ){
|
|
return rc;
|
|
}
|
|
pPtrmap = (u8 *)sqlite3PagerGetData(pDbPage);
|
|
|
|
offset = PTRMAP_PTROFFSET(iPtrmap, key);
|
|
assert( pEType!=0 );
|
|
*pEType = pPtrmap[offset];
|
|
if( pPgno ) *pPgno = get4byte(&pPtrmap[offset+1]);
|
|
|
|
sqlite3PagerUnref(pDbPage);
|
|
if( *pEType<1 || *pEType>PTRMAP_LAZYFREE ) return SQLITE_CORRUPT_BKPT;
|
|
return SQLITE_OK;
|
|
}
|
|
|
|
#else /* if defined SQLITE_OMIT_AUTOVACUUM */
|
|
#define ptrmapPut(w,x,y,z,rc)
|
|
#define ptrmapGet(w,x,y,z) SQLITE_OK
|
|
#define ptrmapPutOvflPtr(x, y, rc)
|
|
#endif
|
|
|
|
/*
|
|
** Given a btree page and a cell index (0 means the first cell on
|
|
** the page, 1 means the second cell, and so forth) return a pointer
|
|
** to the cell content.
|
|
**
|
|
** This routine works only for pages that do not contain overflow cells.
|
|
*/
|
|
#define findCell(P,I) \
|
|
((P)->aData + ((P)->maskPage & get2byte(&(P)->aData[(P)->cellOffset+2*(I)])))
|
|
|
|
// Make sure the pointer map entry for child points to parent
|
|
#if 0
|
|
static int verifyParentChildLink(BtShared *pBt, Pgno parent, Pgno child) {
|
|
Pgno pgno;
|
|
u8 eType;
|
|
int rc = ptrmapGet(pBt, child, &eType, &pgno);
|
|
if( (rc != SQLITE_OK) || (pgno != parent) )
|
|
return SQLITE_CORRUPT_BKPT;
|
|
|
|
return SQLITE_OK;
|
|
}
|
|
#else
|
|
#define verifyParentChildLink(x,y,z) SQLITE_OK
|
|
#endif
|
|
|
|
/*
|
|
** This a more complex version of findCell() that works for
|
|
** pages that do contain overflow cells.
|
|
*/
|
|
static u8 *findOverflowCell(MemPage *pPage, int iCell){
|
|
int i;
|
|
assert( sqlite3_mutex_held(pPage->pBt->mutex) );
|
|
for(i=pPage->nOverflow-1; i>=0; i--){
|
|
int k;
|
|
struct _OvflCell *pOvfl;
|
|
pOvfl = &pPage->aOvfl[i];
|
|
k = pOvfl->idx;
|
|
if( k<=iCell ){
|
|
if( k==iCell ){
|
|
return pOvfl->pCell;
|
|
}
|
|
iCell--;
|
|
}
|
|
}
|
|
return findCell(pPage, iCell);
|
|
}
|
|
|
|
/*
|
|
** Parse a cell content block and fill in the CellInfo structure. There
|
|
** are two versions of this function. btreeParseCell() takes a
|
|
** cell index as the second argument and btreeParseCellPtr()
|
|
** takes a pointer to the body of the cell as its second argument.
|
|
**
|
|
** Within this file, the parseCell() macro can be called instead of
|
|
** btreeParseCellPtr(). Using some compilers, this will be faster.
|
|
*/
|
|
static void btreeParseCellPtr(
|
|
MemPage *pPage, /* Page containing the cell */
|
|
u8 *pCell, /* Pointer to the cell text. */
|
|
CellInfo *pInfo /* Fill in this structure */
|
|
){
|
|
u16 n; /* Number bytes in cell content header */
|
|
u32 nPayload; /* Number of bytes of cell payload */
|
|
|
|
assert( sqlite3_mutex_held(pPage->pBt->mutex) );
|
|
|
|
pInfo->pCell = pCell;
|
|
assert( pPage->leaf==0 || pPage->leaf==1 );
|
|
n = pPage->childPtrSize;
|
|
assert( n==4-4*pPage->leaf );
|
|
if( pPage->intKey ){
|
|
if( pPage->hasData ){
|
|
n += getVarint32(&pCell[n], nPayload);
|
|
}else{
|
|
nPayload = 0;
|
|
}
|
|
n += getVarint(&pCell[n], (u64*)&pInfo->nKey);
|
|
pInfo->nData = nPayload;
|
|
}else{
|
|
pInfo->nData = 0;
|
|
n += getVarint32(&pCell[n], nPayload);
|
|
pInfo->nKey = nPayload;
|
|
}
|
|
pInfo->nPayload = nPayload;
|
|
pInfo->nHeader = n;
|
|
testcase( nPayload==pPage->maxLocal );
|
|
testcase( nPayload==pPage->maxLocal+1 );
|
|
if( likely(nPayload<=pPage->maxLocal) ){
|
|
/* This is the (easy) common case where the entire payload fits
|
|
** on the local page. No overflow is required.
|
|
*/
|
|
if( (pInfo->nSize = (u16)(n+nPayload))<4 ) pInfo->nSize = 4;
|
|
pInfo->nLocal = (u16)nPayload;
|
|
pInfo->iOverflow = 0;
|
|
}else{
|
|
/* If the payload will not fit completely on the local page, we have
|
|
** to decide how much to store locally and how much to spill onto
|
|
** overflow pages. The strategy is to minimize the amount of unused
|
|
** space on overflow pages while keeping the amount of local storage
|
|
** in between minLocal and maxLocal.
|
|
**
|
|
** Warning: changing the way overflow payload is distributed in any
|
|
** way will result in an incompatible file format.
|
|
*/
|
|
int minLocal; /* Minimum amount of payload held locally */
|
|
int maxLocal; /* Maximum amount of payload held locally */
|
|
int surplus; /* Overflow payload available for local storage */
|
|
|
|
minLocal = pPage->minLocal;
|
|
maxLocal = pPage->maxLocal;
|
|
surplus = minLocal + (nPayload - minLocal)%(pPage->pBt->usableSize - 4);
|
|
testcase( surplus==maxLocal );
|
|
testcase( surplus==maxLocal+1 );
|
|
if( surplus <= maxLocal ){
|
|
pInfo->nLocal = (u16)surplus;
|
|
}else{
|
|
pInfo->nLocal = (u16)minLocal;
|
|
}
|
|
pInfo->iOverflow = (u16)(pInfo->nLocal + n);
|
|
pInfo->nSize = pInfo->iOverflow + 4;
|
|
}
|
|
}
|
|
#define parseCell(pPage, iCell, pInfo) \
|
|
btreeParseCellPtr((pPage), findCell((pPage), (iCell)), (pInfo))
|
|
static void btreeParseCell(
|
|
MemPage *pPage, /* Page containing the cell */
|
|
int iCell, /* The cell index. First cell is 0 */
|
|
CellInfo *pInfo /* Fill in this structure */
|
|
){
|
|
parseCell(pPage, iCell, pInfo);
|
|
}
|
|
|
|
/*
|
|
** Compute the total number of bytes that a Cell needs in the cell
|
|
** data area of the btree-page. The return number includes the cell
|
|
** data header and the local payload, but not any overflow page or
|
|
** the space used by the cell pointer.
|
|
*/
|
|
static u16 cellSizePtr(MemPage *pPage, u8 *pCell){
|
|
u8 *pIter = &pCell[pPage->childPtrSize];
|
|
u32 nSize;
|
|
|
|
#ifdef SQLITE_DEBUG
|
|
/* The value returned by this function should always be the same as
|
|
** the (CellInfo.nSize) value found by doing a full parse of the
|
|
** cell. If SQLITE_DEBUG is defined, an assert() at the bottom of
|
|
** this function verifies that this invariant is not violated. */
|
|
CellInfo debuginfo;
|
|
btreeParseCellPtr(pPage, pCell, &debuginfo);
|
|
#endif
|
|
|
|
if( pPage->intKey ){
|
|
u8 *pEnd;
|
|
if( pPage->hasData ){
|
|
pIter += getVarint32(pIter, nSize);
|
|
}else{
|
|
nSize = 0;
|
|
}
|
|
|
|
/* pIter now points at the 64-bit integer key value, a variable length
|
|
** integer. The following block moves pIter to point at the first byte
|
|
** past the end of the key value. */
|
|
pEnd = &pIter[9];
|
|
while( (*pIter++)&0x80 && pIter<pEnd );
|
|
}else{
|
|
pIter += getVarint32(pIter, nSize);
|
|
}
|
|
|
|
testcase( nSize==pPage->maxLocal );
|
|
testcase( nSize==pPage->maxLocal+1 );
|
|
if( nSize>pPage->maxLocal ){
|
|
int minLocal = pPage->minLocal;
|
|
nSize = minLocal + (nSize - minLocal) % (pPage->pBt->usableSize - 4);
|
|
testcase( nSize==pPage->maxLocal );
|
|
testcase( nSize==pPage->maxLocal+1 );
|
|
if( nSize>pPage->maxLocal ){
|
|
nSize = minLocal;
|
|
}
|
|
nSize += 4;
|
|
}
|
|
nSize += (u32)(pIter - pCell);
|
|
|
|
/* The minimum size of any cell is 4 bytes. */
|
|
if( nSize<4 ){
|
|
nSize = 4;
|
|
}
|
|
|
|
assert( nSize==debuginfo.nSize );
|
|
return (u16)nSize;
|
|
}
|
|
|
|
#ifdef SQLITE_DEBUG
|
|
/* This variation on cellSizePtr() is used inside of assert() statements
|
|
** only. */
|
|
static u16 cellSize(MemPage *pPage, int iCell){
|
|
return cellSizePtr(pPage, findCell(pPage, iCell));
|
|
}
|
|
#endif
|
|
|
|
#ifndef SQLITE_OMIT_AUTOVACUUM
|
|
/*
|
|
** If the cell pCell, part of page pPage contains a pointer
|
|
** to an overflow page, insert an entry into the pointer-map
|
|
** for the overflow page.
|
|
*/
|
|
static void ptrmapPutOvflPtr(MemPage *pPage, u8 *pCell, int *pRC){
|
|
CellInfo info;
|
|
if( *pRC ) return;
|
|
assert( pCell!=0 );
|
|
btreeParseCellPtr(pPage, pCell, &info);
|
|
assert( (info.nData+(pPage->intKey?0:info.nKey))==info.nPayload );
|
|
if( info.iOverflow ){
|
|
Pgno ovfl = get4byte(&pCell[info.iOverflow]);
|
|
ptrmapPut(pPage->pBt, ovfl, PTRMAP_OVERFLOW1, pPage->pgno, pRC);
|
|
}
|
|
}
|
|
#endif
|
|
|
|
|
|
/*
|
|
** Defragment the page given. All Cells are moved to the
|
|
** end of the page and all free space is collected into one
|
|
** big FreeBlk that occurs in between the header and cell
|
|
** pointer array and the cell content area.
|
|
*/
|
|
static int defragmentPage(MemPage *pPage){
|
|
int i; /* Loop counter */
|
|
int pc; /* Address of a i-th cell */
|
|
int hdr; /* Offset to the page header */
|
|
int size; /* Size of a cell */
|
|
int usableSize; /* Number of usable bytes on a page */
|
|
int cellOffset; /* Offset to the cell pointer array */
|
|
int cbrk; /* Offset to the cell content area */
|
|
int nCell; /* Number of cells on the page */
|
|
unsigned char *data; /* The page data */
|
|
unsigned char *temp; /* Temp area for cell content */
|
|
int iCellFirst; /* First allowable cell index */
|
|
int iCellLast; /* Last possible cell index */
|
|
|
|
|
|
assert( sqlite3PagerIswriteable(pPage->pDbPage) );
|
|
assert( pPage->pBt!=0 );
|
|
assert( pPage->pBt->usableSize <= SQLITE_MAX_PAGE_SIZE );
|
|
assert( pPage->nOverflow==0 );
|
|
assert( sqlite3_mutex_held(pPage->pBt->mutex) );
|
|
temp = sqlite3PagerTempSpace(pPage->pBt->pPager);
|
|
data = pPage->aData;
|
|
hdr = pPage->hdrOffset;
|
|
cellOffset = pPage->cellOffset;
|
|
nCell = pPage->nCell;
|
|
assert( nCell==get2byte(&data[hdr+3]) );
|
|
usableSize = pPage->pBt->usableSize;
|
|
cbrk = get2byte(&data[hdr+5]);
|
|
memcpy(&temp[cbrk], &data[cbrk], usableSize - cbrk);
|
|
cbrk = usableSize;
|
|
iCellFirst = cellOffset + 2*nCell;
|
|
iCellLast = usableSize - 4;
|
|
for(i=0; i<nCell; i++){
|
|
u8 *pAddr; /* The i-th cell pointer */
|
|
pAddr = &data[cellOffset + i*2];
|
|
pc = get2byte(pAddr);
|
|
testcase( pc==iCellFirst );
|
|
testcase( pc==iCellLast );
|
|
#if !defined(SQLITE_ENABLE_OVERSIZE_CELL_CHECK)
|
|
/* These conditions have already been verified in btreeInitPage()
|
|
** if SQLITE_ENABLE_OVERSIZE_CELL_CHECK is defined
|
|
*/
|
|
if( pc<iCellFirst || pc>iCellLast ){
|
|
return SQLITE_CORRUPT_BKPT;
|
|
}
|
|
#endif
|
|
assert( pc>=iCellFirst && pc<=iCellLast );
|
|
size = cellSizePtr(pPage, &temp[pc]);
|
|
cbrk -= size;
|
|
#if defined(SQLITE_ENABLE_OVERSIZE_CELL_CHECK)
|
|
if( cbrk<iCellFirst ){
|
|
return SQLITE_CORRUPT_BKPT;
|
|
}
|
|
#else
|
|
if( cbrk<iCellFirst || pc+size>usableSize ){
|
|
return SQLITE_CORRUPT_BKPT;
|
|
}
|
|
#endif
|
|
assert( cbrk+size<=usableSize && cbrk>=iCellFirst );
|
|
testcase( cbrk+size==usableSize );
|
|
testcase( pc+size==usableSize );
|
|
memcpy(&data[cbrk], &temp[pc], size);
|
|
put2byte(pAddr, cbrk);
|
|
}
|
|
assert( cbrk>=iCellFirst );
|
|
put2byte(&data[hdr+5], cbrk);
|
|
data[hdr+1] = 0;
|
|
data[hdr+2] = 0;
|
|
data[hdr+7] = 0;
|
|
memset(&data[iCellFirst], 0, cbrk-iCellFirst);
|
|
assert( sqlite3PagerIswriteable(pPage->pDbPage) );
|
|
if( cbrk-iCellFirst!=pPage->nFree ){
|
|
return SQLITE_CORRUPT_BKPT;
|
|
}
|
|
return SQLITE_OK;
|
|
}
|
|
|
|
/*
|
|
** Allocate nByte bytes of space from within the B-Tree page passed
|
|
** as the first argument. Write into *pIdx the index into pPage->aData[]
|
|
** of the first byte of allocated space. Return either SQLITE_OK or
|
|
** an error code (usually SQLITE_CORRUPT).
|
|
**
|
|
** The caller guarantees that there is sufficient space to make the
|
|
** allocation. This routine might need to defragment in order to bring
|
|
** all the space together, however. This routine will avoid using
|
|
** the first two bytes past the cell pointer area since presumably this
|
|
** allocation is being made in order to insert a new cell, so we will
|
|
** also end up needing a new cell pointer.
|
|
*/
|
|
static int allocateSpace(MemPage *pPage, int nByte, int *pIdx){
|
|
const int hdr = pPage->hdrOffset; /* Local cache of pPage->hdrOffset */
|
|
u8 * const data = pPage->aData; /* Local cache of pPage->aData */
|
|
int nFrag; /* Number of fragmented bytes on pPage */
|
|
int top; /* First byte of cell content area */
|
|
int gap; /* First byte of gap between cell pointers and cell content */
|
|
int rc; /* Integer return code */
|
|
int usableSize; /* Usable size of the page */
|
|
|
|
assert( sqlite3PagerIswriteable(pPage->pDbPage) );
|
|
assert( pPage->pBt );
|
|
assert( sqlite3_mutex_held(pPage->pBt->mutex) );
|
|
assert( nByte>=0 ); /* Minimum cell size is 4 */
|
|
assert( pPage->nFree>=nByte );
|
|
assert( pPage->nOverflow==0 );
|
|
usableSize = pPage->pBt->usableSize;
|
|
assert( nByte < usableSize-8 );
|
|
|
|
nFrag = data[hdr+7];
|
|
assert( pPage->cellOffset == hdr + 12 - 4*pPage->leaf );
|
|
gap = pPage->cellOffset + 2*pPage->nCell;
|
|
top = get2byteNotZero(&data[hdr+5]);
|
|
if( gap>top ) return SQLITE_CORRUPT_BKPT;
|
|
testcase( gap+2==top );
|
|
testcase( gap+1==top );
|
|
testcase( gap==top );
|
|
|
|
if( nFrag>=60 ){
|
|
/* Always defragment highly fragmented pages */
|
|
rc = defragmentPage(pPage);
|
|
if( rc ) return rc;
|
|
top = get2byteNotZero(&data[hdr+5]);
|
|
}else if( gap+2<=top ){
|
|
/* Search the freelist looking for a free slot big enough to satisfy
|
|
** the request. The allocation is made from the first free slot in
|
|
** the list that is large enough to accomadate it.
|
|
*/
|
|
int pc, addr;
|
|
for(addr=hdr+1; (pc = get2byte(&data[addr]))>0; addr=pc){
|
|
int size; /* Size of the free slot */
|
|
if( pc>usableSize-4 || pc<addr+4 ){
|
|
return SQLITE_CORRUPT_BKPT;
|
|
}
|
|
size = get2byte(&data[pc+2]);
|
|
if( size>=nByte ){
|
|
int x = size - nByte;
|
|
testcase( x==4 );
|
|
testcase( x==3 );
|
|
if( x<4 ){
|
|
/* Remove the slot from the free-list. Update the number of
|
|
** fragmented bytes within the page. */
|
|
memcpy(&data[addr], &data[pc], 2);
|
|
data[hdr+7] = (u8)(nFrag + x);
|
|
}else if( size+pc > usableSize ){
|
|
return SQLITE_CORRUPT_BKPT;
|
|
}else{
|
|
/* The slot remains on the free-list. Reduce its size to account
|
|
** for the portion used by the new allocation. */
|
|
put2byte(&data[pc+2], x);
|
|
}
|
|
*pIdx = pc + x;
|
|
return SQLITE_OK;
|
|
}
|
|
}
|
|
}
|
|
|
|
/* Check to make sure there is enough space in the gap to satisfy
|
|
** the allocation. If not, defragment.
|
|
*/
|
|
testcase( gap+2+nByte==top );
|
|
if( gap+2+nByte>top ){
|
|
rc = defragmentPage(pPage);
|
|
if( rc ) return rc;
|
|
top = get2byteNotZero(&data[hdr+5]);
|
|
assert( gap+nByte<=top );
|
|
}
|
|
|
|
|
|
/* Allocate memory from the gap in between the cell pointer array
|
|
** and the cell content area. The btreeInitPage() call has already
|
|
** validated the freelist. Given that the freelist is valid, there
|
|
** is no way that the allocation can extend off the end of the page.
|
|
** The assert() below verifies the previous sentence.
|
|
*/
|
|
top -= nByte;
|
|
put2byte(&data[hdr+5], top);
|
|
assert( top+nByte <= pPage->pBt->usableSize );
|
|
*pIdx = top;
|
|
return SQLITE_OK;
|
|
}
|
|
|
|
/*
|
|
** Return a section of the pPage->aData to the freelist.
|
|
** The first byte of the new free block is pPage->aDisk[start]
|
|
** and the size of the block is "size" bytes.
|
|
**
|
|
** Most of the effort here is involved in coalesing adjacent
|
|
** free blocks into a single big free block.
|
|
*/
|
|
static int freeSpace(MemPage *pPage, int start, int size){
|
|
int addr, pbegin, hdr;
|
|
int iLast; /* Largest possible freeblock offset */
|
|
unsigned char *data = pPage->aData;
|
|
|
|
assert( pPage->pBt!=0 );
|
|
assert( sqlite3PagerIswriteable(pPage->pDbPage) );
|
|
assert( start>=pPage->hdrOffset+6+pPage->childPtrSize );
|
|
assert( (start + size)<=pPage->pBt->usableSize );
|
|
assert( sqlite3_mutex_held(pPage->pBt->mutex) );
|
|
assert( size>=0 ); /* Minimum cell size is 4 */
|
|
|
|
if( pPage->pBt->secureDelete ){
|
|
/* Overwrite deleted information with zeros when the secure_delete
|
|
** option is enabled */
|
|
memset(&data[start], 0, size);
|
|
}
|
|
|
|
/* Add the space back into the linked list of freeblocks. Note that
|
|
** even though the freeblock list was checked by btreeInitPage(),
|
|
** btreeInitPage() did not detect overlapping cells or
|
|
** freeblocks that overlapped cells. Nor does it detect when the
|
|
** cell content area exceeds the value in the page header. If these
|
|
** situations arise, then subsequent insert operations might corrupt
|
|
** the freelist. So we do need to check for corruption while scanning
|
|
** the freelist.
|
|
*/
|
|
hdr = pPage->hdrOffset;
|
|
addr = hdr + 1;
|
|
iLast = pPage->pBt->usableSize - 4;
|
|
assert( start<=iLast );
|
|
while( (pbegin = get2byte(&data[addr]))<start && pbegin>0 ){
|
|
if( pbegin<addr+4 ){
|
|
return SQLITE_CORRUPT_BKPT;
|
|
}
|
|
addr = pbegin;
|
|
}
|
|
if( pbegin>iLast ){
|
|
return SQLITE_CORRUPT_BKPT;
|
|
}
|
|
assert( pbegin>addr || pbegin==0 );
|
|
put2byte(&data[addr], start);
|
|
put2byte(&data[start], pbegin);
|
|
put2byte(&data[start+2], size);
|
|
pPage->nFree = pPage->nFree + (u16)size;
|
|
|
|
/* Coalesce adjacent free blocks */
|
|
addr = hdr + 1;
|
|
while( (pbegin = get2byte(&data[addr]))>0 ){
|
|
int pnext, psize, x;
|
|
assert( pbegin>addr );
|
|
assert( pbegin<=pPage->pBt->usableSize-4 );
|
|
pnext = get2byte(&data[pbegin]);
|
|
psize = get2byte(&data[pbegin+2]);
|
|
if( pbegin + psize + 3 >= pnext && pnext>0 ){
|
|
int frag = pnext - (pbegin+psize);
|
|
if( (frag<0) || (frag>(int)data[hdr+7]) ){
|
|
return SQLITE_CORRUPT_BKPT;
|
|
}
|
|
data[hdr+7] -= (u8)frag;
|
|
x = get2byte(&data[pnext]);
|
|
put2byte(&data[pbegin], x);
|
|
x = pnext + get2byte(&data[pnext+2]) - pbegin;
|
|
put2byte(&data[pbegin+2], x);
|
|
}else{
|
|
addr = pbegin;
|
|
}
|
|
}
|
|
|
|
/* If the cell content area begins with a freeblock, remove it. */
|
|
if( data[hdr+1]==data[hdr+5] && data[hdr+2]==data[hdr+6] ){
|
|
int top;
|
|
pbegin = get2byte(&data[hdr+1]);
|
|
memcpy(&data[hdr+1], &data[pbegin], 2);
|
|
top = get2byte(&data[hdr+5]) + get2byte(&data[pbegin+2]);
|
|
put2byte(&data[hdr+5], top);
|
|
}
|
|
assert( sqlite3PagerIswriteable(pPage->pDbPage) );
|
|
return SQLITE_OK;
|
|
}
|
|
|
|
/*
|
|
** Decode the flags byte (the first byte of the header) for a page
|
|
** and initialize fields of the MemPage structure accordingly.
|
|
**
|
|
** Only the following combinations are supported. Anything different
|
|
** indicates a corrupt database files:
|
|
**
|
|
** PTF_ZERODATA
|
|
** PTF_ZERODATA | PTF_LEAF
|
|
** PTF_LEAFDATA | PTF_INTKEY
|
|
** PTF_LEAFDATA | PTF_INTKEY | PTF_LEAF
|
|
*/
|
|
static int decodeFlags(MemPage *pPage, int flagByte){
|
|
BtShared *pBt; /* A copy of pPage->pBt */
|
|
|
|
assert( pPage->hdrOffset==(pPage->pgno==1 ? 100 : 0) );
|
|
assert( sqlite3_mutex_held(pPage->pBt->mutex) );
|
|
pPage->leaf = (u8)(flagByte>>3); assert( PTF_LEAF == 1<<3 );
|
|
flagByte &= ~PTF_LEAF;
|
|
pPage->childPtrSize = 4-4*pPage->leaf;
|
|
pBt = pPage->pBt;
|
|
if( flagByte==(PTF_LEAFDATA | PTF_INTKEY) ){
|
|
pPage->intKey = 1;
|
|
pPage->hasData = pPage->leaf;
|
|
pPage->maxLocal = pBt->maxLeaf;
|
|
pPage->minLocal = pBt->minLeaf;
|
|
}else if( flagByte==PTF_ZERODATA ){
|
|
pPage->intKey = 0;
|
|
pPage->hasData = 0;
|
|
pPage->maxLocal = pBt->maxLocal;
|
|
pPage->minLocal = pBt->minLocal;
|
|
}else{
|
|
return SQLITE_CORRUPT_BKPT;
|
|
}
|
|
return SQLITE_OK;
|
|
}
|
|
|
|
/*
|
|
** Initialize the auxiliary information for a disk block.
|
|
**
|
|
** Return SQLITE_OK on success. If we see that the page does
|
|
** not contain a well-formed database page, then return
|
|
** SQLITE_CORRUPT. Note that a return of SQLITE_OK does not
|
|
** guarantee that the page is well-formed. It only shows that
|
|
** we failed to detect any corruption.
|
|
*/
|
|
static int btreeInitPage(MemPage *pPage){
|
|
|
|
assert( pPage->pBt!=0 );
|
|
assert( sqlite3_mutex_held(pPage->pBt->mutex) );
|
|
assert( pPage->pgno==sqlite3PagerPagenumber(pPage->pDbPage) );
|
|
assert( pPage == sqlite3PagerGetExtra(pPage->pDbPage) );
|
|
assert( pPage->aData == sqlite3PagerGetData(pPage->pDbPage) );
|
|
|
|
if( !pPage->isInit ){
|
|
u16 pc; /* Address of a freeblock within pPage->aData[] */
|
|
u8 hdr; /* Offset to beginning of page header */
|
|
u8 *data; /* Equal to pPage->aData */
|
|
BtShared *pBt; /* The main btree structure */
|
|
int usableSize; /* Amount of usable space on each page */
|
|
u16 cellOffset; /* Offset from start of page to first cell pointer */
|
|
int nFree; /* Number of unused bytes on the page */
|
|
int top; /* First byte of the cell content area */
|
|
int iCellFirst; /* First allowable cell or freeblock offset */
|
|
int iCellLast; /* Last possible cell or freeblock offset */
|
|
|
|
pBt = pPage->pBt;
|
|
|
|
hdr = pPage->hdrOffset;
|
|
data = pPage->aData;
|
|
if( decodeFlags(pPage, data[hdr]) ) return SQLITE_CORRUPT_BKPT;
|
|
assert( pBt->pageSize>=512 && pBt->pageSize<=65536 );
|
|
pPage->maskPage = (u16)(pBt->pageSize - 1);
|
|
pPage->nOverflow = 0;
|
|
usableSize = pBt->usableSize;
|
|
pPage->cellOffset = cellOffset = hdr + 12 - 4*pPage->leaf;
|
|
top = get2byteNotZero(&data[hdr+5]);
|
|
pPage->nCell = get2byte(&data[hdr+3]);
|
|
if( pPage->nCell>MX_CELL(pBt) ){
|
|
/* To many cells for a single page. The page must be corrupt */
|
|
return SQLITE_CORRUPT_BKPT;
|
|
}
|
|
testcase( pPage->nCell==MX_CELL(pBt) );
|
|
|
|
/* A malformed database page might cause us to read past the end
|
|
** of page when parsing a cell.
|
|
**
|
|
** The following block of code checks early to see if a cell extends
|
|
** past the end of a page boundary and causes SQLITE_CORRUPT to be
|
|
** returned if it does.
|
|
*/
|
|
iCellFirst = cellOffset + 2*pPage->nCell;
|
|
iCellLast = usableSize - 4;
|
|
#if defined(SQLITE_ENABLE_OVERSIZE_CELL_CHECK)
|
|
{
|
|
int i; /* Index into the cell pointer array */
|
|
int sz; /* Size of a cell */
|
|
|
|
if( !pPage->leaf ) iCellLast--;
|
|
for(i=0; i<pPage->nCell; i++){
|
|
pc = get2byte(&data[cellOffset+i*2]);
|
|
testcase( pc==iCellFirst );
|
|
testcase( pc==iCellLast );
|
|
if( pc<iCellFirst || pc>iCellLast ){
|
|
return SQLITE_CORRUPT_BKPT;
|
|
}
|
|
sz = cellSizePtr(pPage, &data[pc]);
|
|
testcase( pc+sz==usableSize );
|
|
if( pc+sz>usableSize ){
|
|
return SQLITE_CORRUPT_BKPT;
|
|
}
|
|
}
|
|
if( !pPage->leaf ) iCellLast++;
|
|
}
|
|
#endif
|
|
|
|
/* Compute the total free space on the page */
|
|
pc = get2byte(&data[hdr+1]);
|
|
nFree = data[hdr+7] + top;
|
|
while( pc>0 ){
|
|
u16 next, size;
|
|
if( pc<iCellFirst || pc>iCellLast ){
|
|
/* Start of free block is off the page */
|
|
return SQLITE_CORRUPT_BKPT;
|
|
}
|
|
next = get2byte(&data[pc]);
|
|
size = get2byte(&data[pc+2]);
|
|
if( (next>0 && next<=pc+size+3) || pc+size>usableSize ){
|
|
/* Free blocks must be in ascending order. And the last byte of
|
|
** the free-block must lie on the database page. */
|
|
return SQLITE_CORRUPT_BKPT;
|
|
}
|
|
nFree = nFree + size;
|
|
pc = next;
|
|
}
|
|
|
|
/* At this point, nFree contains the sum of the offset to the start
|
|
** of the cell-content area plus the number of free bytes within
|
|
** the cell-content area. If this is greater than the usable-size
|
|
** of the page, then the page must be corrupted. This check also
|
|
** serves to verify that the offset to the start of the cell-content
|
|
** area, according to the page header, lies within the page.
|
|
*/
|
|
if( nFree>usableSize ){
|
|
return SQLITE_CORRUPT_BKPT;
|
|
}
|
|
pPage->nFree = (u16)(nFree - iCellFirst);
|
|
pPage->isInit = 1;
|
|
}
|
|
return SQLITE_OK;
|
|
}
|
|
|
|
/*
|
|
** Set up a raw page so that it looks like a database page holding
|
|
** no entries.
|
|
*/
|
|
static void zeroPage(MemPage *pPage, int flags){
|
|
unsigned char *data = pPage->aData;
|
|
BtShared *pBt = pPage->pBt;
|
|
u8 hdr = pPage->hdrOffset;
|
|
u16 first;
|
|
|
|
assert( sqlite3PagerPagenumber(pPage->pDbPage)==pPage->pgno );
|
|
assert( sqlite3PagerGetExtra(pPage->pDbPage) == (void*)pPage );
|
|
assert( sqlite3PagerGetData(pPage->pDbPage) == data );
|
|
assert( sqlite3PagerIswriteable(pPage->pDbPage) );
|
|
assert( sqlite3_mutex_held(pBt->mutex) );
|
|
if( pBt->secureDelete ){
|
|
memset(&data[hdr], 0, pBt->usableSize - hdr);
|
|
}
|
|
data[hdr] = (char)flags;
|
|
first = hdr + 8 + 4*((flags&PTF_LEAF)==0 ?1:0);
|
|
memset(&data[hdr+1], 0, 4);
|
|
data[hdr+7] = 0;
|
|
put2byte(&data[hdr+5], pBt->usableSize);
|
|
pPage->nFree = (u16)(pBt->usableSize - first);
|
|
decodeFlags(pPage, flags);
|
|
pPage->hdrOffset = hdr;
|
|
pPage->cellOffset = first;
|
|
pPage->nOverflow = 0;
|
|
assert( pBt->pageSize>=512 && pBt->pageSize<=65536 );
|
|
pPage->maskPage = (u16)(pBt->pageSize - 1);
|
|
pPage->nCell = 0;
|
|
pPage->isInit = 1;
|
|
}
|
|
|
|
|
|
/*
|
|
** Convert a DbPage obtained from the pager into a MemPage used by
|
|
** the btree layer.
|
|
*/
|
|
static MemPage *btreePageFromDbPage(DbPage *pDbPage, Pgno pgno, BtShared *pBt){
|
|
MemPage *pPage = (MemPage*)sqlite3PagerGetExtra(pDbPage);
|
|
pPage->aData = sqlite3PagerGetData(pDbPage);
|
|
pPage->pDbPage = pDbPage;
|
|
pPage->pBt = pBt;
|
|
pPage->pgno = pgno;
|
|
pPage->hdrOffset = pPage->pgno==1 ? 100 : 0;
|
|
return pPage;
|
|
}
|
|
|
|
/*
|
|
** Get a page from the pager. Initialize the MemPage.pBt and
|
|
** MemPage.aData elements if needed.
|
|
**
|
|
** If the noContent flag is set, it means that we do not care about
|
|
** the content of the page at this time. So do not go to the disk
|
|
** to fetch the content. Just fill in the content with zeros for now.
|
|
** If in the future we call sqlite3PagerWrite() on this page, that
|
|
** means we have started to be concerned about content and the disk
|
|
** read should occur at that point.
|
|
*/
|
|
static int btreeGetPage(
|
|
BtShared *pBt, /* The btree */
|
|
Pgno pgno, /* Number of the page to fetch */
|
|
MemPage **ppPage, /* Return the page in this parameter */
|
|
int noContent /* Do not load page content if true */
|
|
){
|
|
int rc;
|
|
DbPage *pDbPage;
|
|
|
|
assert( sqlite3_mutex_held(pBt->mutex) );
|
|
rc = sqlite3PagerAcquire(pBt->pPager, pgno, (DbPage**)&pDbPage, noContent);
|
|
if( rc ) return rc;
|
|
*ppPage = btreePageFromDbPage(pDbPage, pgno, pBt);
|
|
return SQLITE_OK;
|
|
}
|
|
|
|
/*
|
|
** Retrieve a page from the pager cache. If the requested page is not
|
|
** already in the pager cache return NULL. Initialize the MemPage.pBt and
|
|
** MemPage.aData elements if needed.
|
|
*/
|
|
static MemPage *btreePageLookup(BtShared *pBt, Pgno pgno){
|
|
DbPage *pDbPage;
|
|
assert( sqlite3_mutex_held(pBt->mutex) );
|
|
pDbPage = sqlite3PagerLookup(pBt->pPager, pgno);
|
|
if( pDbPage ){
|
|
return btreePageFromDbPage(pDbPage, pgno, pBt);
|
|
}
|
|
return 0;
|
|
}
|
|
|
|
/*
|
|
** Return the size of the database file in pages. If there is any kind of
|
|
** error, return ((unsigned int)-1).
|
|
*/
|
|
static Pgno btreePagecount(BtShared *pBt){
|
|
return pBt->nPage;
|
|
}
|
|
SQLITE_PRIVATE u32 sqlite3BtreeLastPage(Btree *p){
|
|
assert( sqlite3BtreeHoldsMutex(p) );
|
|
assert( ((p->pBt->nPage)&0x8000000)==0 );
|
|
return (int)btreePagecount(p->pBt);
|
|
}
|
|
|
|
/*
|
|
** Get a page from the pager and initialize it. This routine is just a
|
|
** convenience wrapper around separate calls to btreeGetPage() and
|
|
** btreeInitPage().
|
|
**
|
|
** If an error occurs, then the value *ppPage is set to is undefined. It
|
|
** may remain unchanged, or it may be set to an invalid value.
|
|
*/
|
|
static int getAndInitPage(
|
|
BtShared *pBt, /* The database file */
|
|
Pgno pgno, /* Number of the page to get */
|
|
MemPage **ppPage /* Write the page pointer here */
|
|
){
|
|
int rc;
|
|
assert( sqlite3_mutex_held(pBt->mutex) );
|
|
|
|
if( pgno>btreePagecount(pBt) ){
|
|
rc = SQLITE_CORRUPT_BKPT;
|
|
}else{
|
|
rc = btreeGetPage(pBt, pgno, ppPage, 0);
|
|
if( rc==SQLITE_OK ){
|
|
rc = btreeInitPage(*ppPage);
|
|
if( rc!=SQLITE_OK ){
|
|
releasePage(*ppPage);
|
|
}
|
|
}
|
|
}
|
|
|
|
testcase( pgno==0 );
|
|
assert( pgno!=0 || rc==SQLITE_CORRUPT );
|
|
return rc;
|
|
}
|
|
|
|
/*
|
|
** Release a MemPage. This should be called once for each prior
|
|
** call to btreeGetPage.
|
|
*/
|
|
static void releasePage(MemPage *pPage){
|
|
if( pPage ){
|
|
assert( pPage->aData );
|
|
assert( pPage->pBt );
|
|
assert( sqlite3PagerGetExtra(pPage->pDbPage) == (void*)pPage );
|
|
assert( sqlite3PagerGetData(pPage->pDbPage)==pPage->aData );
|
|
assert( sqlite3_mutex_held(pPage->pBt->mutex) );
|
|
sqlite3PagerUnref(pPage->pDbPage);
|
|
}
|
|
}
|
|
|
|
/*
|
|
** During a rollback, when the pager reloads information into the cache
|
|
** so that the cache is restored to its original state at the start of
|
|
** the transaction, for each page restored this routine is called.
|
|
**
|
|
** This routine needs to reset the extra data section at the end of the
|
|
** page to agree with the restored data.
|
|
*/
|
|
static void pageReinit(DbPage *pData){
|
|
MemPage *pPage;
|
|
pPage = (MemPage *)sqlite3PagerGetExtra(pData);
|
|
assert( sqlite3PagerPageRefcount(pData)>0 );
|
|
if( pPage->isInit ){
|
|
assert( sqlite3_mutex_held(pPage->pBt->mutex) );
|
|
pPage->isInit = 0;
|
|
if( sqlite3PagerPageRefcount(pData)>1 ){
|
|
/* pPage might not be a btree page; it might be an overflow page
|
|
** or ptrmap page or a free page. In those cases, the following
|
|
** call to btreeInitPage() will likely return SQLITE_CORRUPT.
|
|
** But no harm is done by this. And it is very important that
|
|
** btreeInitPage() be called on every btree page so we make
|
|
** the call for every page that comes in for re-initing. */
|
|
btreeInitPage(pPage);
|
|
}
|
|
}
|
|
}
|
|
|
|
/*
|
|
** Invoke the busy handler for a btree.
|
|
*/
|
|
static int btreeInvokeBusyHandler(void *pArg){
|
|
BtShared *pBt = (BtShared*)pArg;
|
|
assert( pBt->db );
|
|
assert( sqlite3_mutex_held(pBt->db->mutex) );
|
|
return sqlite3InvokeBusyHandler(&pBt->db->busyHandler);
|
|
}
|
|
|
|
/*
|
|
** Open a database file.
|
|
**
|
|
** zFilename is the name of the database file. If zFilename is NULL
|
|
** then an ephemeral database is created. The ephemeral database might
|
|
** be exclusively in memory, or it might use a disk-based memory cache.
|
|
** Either way, the ephemeral database will be automatically deleted
|
|
** when sqlite3BtreeClose() is called.
|
|
**
|
|
** If zFilename is ":memory:" then an in-memory database is created
|
|
** that is automatically destroyed when it is closed.
|
|
**
|
|
** The "flags" parameter is a bitmask that might contain bits
|
|
** BTREE_OMIT_JOURNAL and/or BTREE_NO_READLOCK. The BTREE_NO_READLOCK
|
|
** bit is also set if the SQLITE_NoReadlock flags is set in db->flags.
|
|
** These flags are passed through into sqlite3PagerOpen() and must
|
|
** be the same values as PAGER_OMIT_JOURNAL and PAGER_NO_READLOCK.
|
|
**
|
|
** If the database is already opened in the same database connection
|
|
** and we are in shared cache mode, then the open will fail with an
|
|
** SQLITE_CONSTRAINT error. We cannot allow two or more BtShared
|
|
** objects in the same database connection since doing so will lead
|
|
** to problems with locking.
|
|
*/
|
|
SQLITE_PRIVATE int sqlite3BtreeOpen(
|
|
const char *zFilename, /* Name of the file containing the BTree database */
|
|
sqlite3 *db, /* Associated database handle */
|
|
Btree **ppBtree, /* Pointer to new Btree object written here */
|
|
int flags, /* Options */
|
|
int vfsFlags /* Flags passed through to sqlite3_vfs.xOpen() */
|
|
){
|
|
sqlite3_vfs *pVfs; /* The VFS to use for this btree */
|
|
BtShared *pBt = 0; /* Shared part of btree structure */
|
|
Btree *p; /* Handle to return */
|
|
sqlite3_mutex *mutexOpen = 0; /* Prevents a race condition. Ticket #3537 */
|
|
int rc = SQLITE_OK; /* Result code from this function */
|
|
u8 nReserve; /* Byte of unused space on each page */
|
|
unsigned char zDbHeader[100]; /* Database header content */
|
|
|
|
/* True if opening an ephemeral, temporary database */
|
|
const int isTempDb = zFilename==0 || zFilename[0]==0;
|
|
|
|
/* Set the variable isMemdb to true for an in-memory database, or
|
|
** false for a file-based database.
|
|
*/
|
|
#ifdef SQLITE_OMIT_MEMORYDB
|
|
const int isMemdb = 0;
|
|
#else
|
|
const int isMemdb = (zFilename && strcmp(zFilename, ":memory:")==0)
|
|
|| (isTempDb && sqlite3TempInMemory(db));
|
|
#endif
|
|
|
|
assert( db!=0 );
|
|
assert( sqlite3_mutex_held(db->mutex) );
|
|
assert( (flags&0xff)==flags ); /* flags fit in 8 bits */
|
|
|
|
/* Only a BTREE_SINGLE database can be BTREE_UNORDERED */
|
|
assert( (flags & BTREE_UNORDERED)==0 || (flags & BTREE_SINGLE)!=0 );
|
|
|
|
/* A BTREE_SINGLE database is always a temporary and/or ephemeral */
|
|
assert( (flags & BTREE_SINGLE)==0 || isTempDb );
|
|
|
|
if( db->flags & SQLITE_NoReadlock ){
|
|
flags |= BTREE_NO_READLOCK;
|
|
}
|
|
if( isMemdb ){
|
|
flags |= BTREE_MEMORY;
|
|
}
|
|
if( (vfsFlags & SQLITE_OPEN_MAIN_DB)!=0 && (isMemdb || isTempDb) ){
|
|
vfsFlags = (vfsFlags & ~SQLITE_OPEN_MAIN_DB) | SQLITE_OPEN_TEMP_DB;
|
|
}
|
|
pVfs = db->pVfs;
|
|
p = sqlite3MallocZero(sizeof(Btree));
|
|
if( !p ){
|
|
return SQLITE_NOMEM;
|
|
}
|
|
p->inTrans = TRANS_NONE;
|
|
p->db = db;
|
|
#ifndef SQLITE_OMIT_SHARED_CACHE
|
|
p->lock.pBtree = p;
|
|
p->lock.iTable = 1;
|
|
#endif
|
|
|
|
#if !defined(SQLITE_OMIT_SHARED_CACHE) && !defined(SQLITE_OMIT_DISKIO)
|
|
/*
|
|
** If this Btree is a candidate for shared cache, try to find an
|
|
** existing BtShared object that we can share with
|
|
*/
|
|
if( isMemdb==0 && isTempDb==0 ){
|
|
if( vfsFlags & SQLITE_OPEN_SHAREDCACHE ){
|
|
int nFullPathname = pVfs->mxPathname+1;
|
|
char *zFullPathname = sqlite3Malloc(nFullPathname);
|
|
sqlite3_mutex *mutexShared;
|
|
p->sharable = 1;
|
|
if( !zFullPathname ){
|
|
sqlite3_free(p);
|
|
return SQLITE_NOMEM;
|
|
}
|
|
sqlite3OsFullPathname(pVfs, zFilename, nFullPathname, zFullPathname);
|
|
mutexOpen = sqlite3MutexAlloc(SQLITE_MUTEX_STATIC_OPEN);
|
|
sqlite3_mutex_enter(mutexOpen);
|
|
mutexShared = sqlite3MutexAlloc(SQLITE_MUTEX_STATIC_MASTER);
|
|
sqlite3_mutex_enter(mutexShared);
|
|
for(pBt=GLOBAL(BtShared*,sqlite3SharedCacheList); pBt; pBt=pBt->pNext){
|
|
assert( pBt->nRef>0 );
|
|
if( 0==strcmp(zFullPathname, sqlite3PagerFilename(pBt->pPager))
|
|
&& sqlite3PagerVfs(pBt->pPager)==pVfs ){
|
|
int iDb;
|
|
for(iDb=db->nDb-1; iDb>=0; iDb--){
|
|
Btree *pExisting = db->aDb[iDb].pBt;
|
|
if( pExisting && pExisting->pBt==pBt ){
|
|
sqlite3_mutex_leave(mutexShared);
|
|
sqlite3_mutex_leave(mutexOpen);
|
|
sqlite3_free(zFullPathname);
|
|
sqlite3_free(p);
|
|
return SQLITE_CONSTRAINT;
|
|
}
|
|
}
|
|
p->pBt = pBt;
|
|
pBt->nRef++;
|
|
break;
|
|
}
|
|
}
|
|
sqlite3_mutex_leave(mutexShared);
|
|
sqlite3_free(zFullPathname);
|
|
}
|
|
#ifdef SQLITE_DEBUG
|
|
else{
|
|
/* In debug mode, we mark all persistent databases as sharable
|
|
** even when they are not. This exercises the locking code and
|
|
** gives more opportunity for asserts(sqlite3_mutex_held())
|
|
** statements to find locking problems.
|
|
*/
|
|
p->sharable = 1;
|
|
}
|
|
#endif
|
|
}
|
|
#endif
|
|
if( pBt==0 ){
|
|
/*
|
|
** The following asserts make sure that structures used by the btree are
|
|
** the right size. This is to guard against size changes that result
|
|
** when compiling on a different architecture.
|
|
*/
|
|
assert( sizeof(i64)==8 || sizeof(i64)==4 );
|
|
assert( sizeof(u64)==8 || sizeof(u64)==4 );
|
|
assert( sizeof(u32)==4 );
|
|
assert( sizeof(u16)==2 );
|
|
assert( sizeof(Pgno)==4 );
|
|
|
|
pBt = sqlite3MallocZero( sizeof(*pBt) );
|
|
if( pBt==0 ){
|
|
rc = SQLITE_NOMEM;
|
|
goto btree_open_out;
|
|
}
|
|
rc = sqlite3PagerOpen(pVfs, &pBt->pPager, zFilename,
|
|
EXTRA_SIZE, flags, vfsFlags, pageReinit);
|
|
if( rc==SQLITE_OK ){
|
|
rc = sqlite3PagerReadFileheader(pBt->pPager,sizeof(zDbHeader),zDbHeader);
|
|
}
|
|
if( rc!=SQLITE_OK ){
|
|
goto btree_open_out;
|
|
}
|
|
pBt->openFlags = (u8)flags;
|
|
pBt->db = db;
|
|
sqlite3PagerSetBusyhandler(pBt->pPager, btreeInvokeBusyHandler, pBt);
|
|
p->pBt = pBt;
|
|
|
|
pBt->pCursor = 0;
|
|
pBt->pPage1 = 0;
|
|
pBt->readOnly = sqlite3PagerIsreadonly(pBt->pPager);
|
|
#ifdef SQLITE_SECURE_DELETE
|
|
pBt->secureDelete = 1;
|
|
#endif
|
|
|
|
// The database header just read could be corrupt but a valid header could exist in the WAL
|
|
// in a page1 frame. The original code below will accept and use any valid-looking page size
|
|
// in the potentially corrupt header, and use 0 otherwise. In either case, once Page1 is read
|
|
// using the pager (which will read the page from the WAL if the page is valid and present there)
|
|
// its header is parsed any any incorrect parameters obtained from the bad header will be
|
|
// corrected. However, in the former case where the page size in the initial header appears to be
|
|
// valid but is not actually correct, then the Pager Codec will be told the wrong page size. This
|
|
// causes a checksumming pager codec to fail the check on Page1, so a valid Page1 and db header
|
|
// cannot be read, and the database cannot be used. Since in the latter case the pager codec will
|
|
// be given a default page which can be used to read and validate Page1 (which can be read as a
|
|
// default sized page or the configured size), it is better here to just assume that the page
|
|
// size in the initial db header is not valid. This also causes two vacuum related parameters to
|
|
// use defaults but that will be corrected once page1 is read.
|
|
//
|
|
//pBt->pageSize = (zDbHeader[16]<<8) | (zDbHeader[17]<<16);
|
|
//if( pBt->pageSize<512 || pBt->pageSize>SQLITE_MAX_PAGE_SIZE
|
|
// || ((pBt->pageSize-1)&pBt->pageSize)!=0 ){
|
|
if(1) {
|
|
pBt->pageSize = 0;
|
|
#ifndef SQLITE_OMIT_AUTOVACUUM
|
|
/* If the magic name ":memory:" will create an in-memory database, then
|
|
** leave the autoVacuum mode at 0 (do not auto-vacuum), even if
|
|
** SQLITE_DEFAULT_AUTOVACUUM is true. On the other hand, if
|
|
** SQLITE_OMIT_MEMORYDB has been defined, then ":memory:" is just a
|
|
** regular file-name. In this case the auto-vacuum applies as per normal.
|
|
*/
|
|
if( zFilename && !isMemdb ){
|
|
pBt->autoVacuum = (SQLITE_DEFAULT_AUTOVACUUM ? 1 : 0);
|
|
pBt->incrVacuum = (SQLITE_DEFAULT_AUTOVACUUM==2 ? 1 : 0);
|
|
}
|
|
#endif
|
|
nReserve = 0;
|
|
}else{
|
|
nReserve = zDbHeader[20];
|
|
pBt->pageSizeFixed = 1;
|
|
#ifndef SQLITE_OMIT_AUTOVACUUM
|
|
pBt->autoVacuum = (get4byte(&zDbHeader[36 + 4*4])?1:0);
|
|
pBt->incrVacuum = (get4byte(&zDbHeader[36 + 7*4])?1:0);
|
|
#endif
|
|
}
|
|
rc = sqlite3PagerSetPagesize(pBt->pPager, &pBt->pageSize, nReserve);
|
|
if( rc ) goto btree_open_out;
|
|
pBt->usableSize = pBt->pageSize - nReserve;
|
|
assert( (pBt->pageSize & 7)==0 ); /* 8-byte alignment of pageSize */
|
|
|
|
#if !defined(SQLITE_OMIT_SHARED_CACHE) && !defined(SQLITE_OMIT_DISKIO)
|
|
/* Add the new BtShared object to the linked list sharable BtShareds.
|
|
*/
|
|
if( p->sharable ){
|
|
sqlite3_mutex *mutexShared;
|
|
pBt->nRef = 1;
|
|
mutexShared = sqlite3MutexAlloc(SQLITE_MUTEX_STATIC_MASTER);
|
|
if( SQLITE_THREADSAFE && sqlite3GlobalConfig.bCoreMutex ){
|
|
pBt->mutex = sqlite3MutexAlloc(SQLITE_MUTEX_FAST);
|
|
if( pBt->mutex==0 ){
|
|
rc = SQLITE_NOMEM;
|
|
db->mallocFailed = 0;
|
|
goto btree_open_out;
|
|
}
|
|
}
|
|
sqlite3_mutex_enter(mutexShared);
|
|
pBt->pNext = GLOBAL(BtShared*,sqlite3SharedCacheList);
|
|
GLOBAL(BtShared*,sqlite3SharedCacheList) = pBt;
|
|
sqlite3_mutex_leave(mutexShared);
|
|
}
|
|
#endif
|
|
}
|
|
|
|
#if !defined(SQLITE_OMIT_SHARED_CACHE) && !defined(SQLITE_OMIT_DISKIO)
|
|
/* If the new Btree uses a sharable pBtShared, then link the new
|
|
** Btree into the list of all sharable Btrees for the same connection.
|
|
** The list is kept in ascending order by pBt address.
|
|
*/
|
|
if( p->sharable ){
|
|
int i;
|
|
Btree *pSib;
|
|
for(i=0; i<db->nDb; i++){
|
|
if( (pSib = db->aDb[i].pBt)!=0 && pSib->sharable ){
|
|
while( pSib->pPrev ){ pSib = pSib->pPrev; }
|
|
if( p->pBt<pSib->pBt ){
|
|
p->pNext = pSib;
|
|
p->pPrev = 0;
|
|
pSib->pPrev = p;
|
|
}else{
|
|
while( pSib->pNext && pSib->pNext->pBt<p->pBt ){
|
|
pSib = pSib->pNext;
|
|
}
|
|
p->pNext = pSib->pNext;
|
|
p->pPrev = pSib;
|
|
if( p->pNext ){
|
|
p->pNext->pPrev = p;
|
|
}
|
|
pSib->pNext = p;
|
|
}
|
|
break;
|
|
}
|
|
}
|
|
}
|
|
#endif
|
|
*ppBtree = p;
|
|
|
|
btree_open_out:
|
|
if( rc!=SQLITE_OK ){
|
|
if( pBt && pBt->pPager ){
|
|
sqlite3PagerClose(pBt->pPager);
|
|
}
|
|
sqlite3_free(pBt);
|
|
sqlite3_free(p);
|
|
*ppBtree = 0;
|
|
}else{
|
|
/* If the B-Tree was successfully opened, set the pager-cache size to the
|
|
** default value. Except, when opening on an existing shared pager-cache,
|
|
** do not change the pager-cache size.
|
|
*/
|
|
if( sqlite3BtreeSchema(p, 0, 0)==0 ){
|
|
sqlite3PagerSetCachesize(p->pBt->pPager, SQLITE_DEFAULT_CACHE_SIZE);
|
|
}
|
|
}
|
|
if( mutexOpen ){
|
|
assert( sqlite3_mutex_held(mutexOpen) );
|
|
sqlite3_mutex_leave(mutexOpen);
|
|
}
|
|
return rc;
|
|
}
|
|
|
|
/*
|
|
** Decrement the BtShared.nRef counter. When it reaches zero,
|
|
** remove the BtShared structure from the sharing list. Return
|
|
** true if the BtShared.nRef counter reaches zero and return
|
|
** false if it is still positive.
|
|
*/
|
|
static int removeFromSharingList(BtShared *pBt){
|
|
#ifndef SQLITE_OMIT_SHARED_CACHE
|
|
sqlite3_mutex *pMaster;
|
|
BtShared *pList;
|
|
int removed = 0;
|
|
|
|
assert( sqlite3_mutex_notheld(pBt->mutex) );
|
|
pMaster = sqlite3MutexAlloc(SQLITE_MUTEX_STATIC_MASTER);
|
|
sqlite3_mutex_enter(pMaster);
|
|
pBt->nRef--;
|
|
if( pBt->nRef<=0 ){
|
|
if( GLOBAL(BtShared*,sqlite3SharedCacheList)==pBt ){
|
|
GLOBAL(BtShared*,sqlite3SharedCacheList) = pBt->pNext;
|
|
}else{
|
|
pList = GLOBAL(BtShared*,sqlite3SharedCacheList);
|
|
while( ALWAYS(pList) && pList->pNext!=pBt ){
|
|
pList=pList->pNext;
|
|
}
|
|
if( ALWAYS(pList) ){
|
|
pList->pNext = pBt->pNext;
|
|
}
|
|
}
|
|
if( SQLITE_THREADSAFE ){
|
|
sqlite3_mutex_free(pBt->mutex);
|
|
}
|
|
removed = 1;
|
|
}
|
|
sqlite3_mutex_leave(pMaster);
|
|
return removed;
|
|
#else
|
|
return 1;
|
|
#endif
|
|
}
|
|
|
|
/*
|
|
** Make sure pBt->pTmpSpace points to an allocation of
|
|
** MX_CELL_SIZE(pBt) bytes.
|
|
*/
|
|
static void allocateTempSpace(BtShared *pBt){
|
|
if( !pBt->pTmpSpace ){
|
|
pBt->pTmpSpace = sqlite3PageMalloc( pBt->pageSize );
|
|
}
|
|
}
|
|
|
|
/*
|
|
** Free the pBt->pTmpSpace allocation
|
|
*/
|
|
static void freeTempSpace(BtShared *pBt){
|
|
sqlite3PageFree( pBt->pTmpSpace);
|
|
pBt->pTmpSpace = 0;
|
|
}
|
|
|
|
/*
|
|
** Close an open database and invalidate all cursors.
|
|
*/
|
|
SQLITE_PRIVATE int sqlite3BtreeClose(Btree *p){
|
|
BtShared *pBt = p->pBt;
|
|
BtCursor *pCur;
|
|
|
|
/* Close all cursors opened via this handle. */
|
|
assert( sqlite3_mutex_held(p->db->mutex) );
|
|
sqlite3BtreeEnter(p);
|
|
pCur = pBt->pCursor;
|
|
while( pCur ){
|
|
BtCursor *pTmp = pCur;
|
|
pCur = pCur->pNext;
|
|
if( pTmp->pBtree==p ){
|
|
sqlite3BtreeCloseCursor(pTmp);
|
|
}
|
|
}
|
|
|
|
/* Rollback any active transaction and free the handle structure.
|
|
** The call to sqlite3BtreeRollback() drops any table-locks held by
|
|
** this handle.
|
|
*/
|
|
sqlite3BtreeRollback(p);
|
|
sqlite3BtreeLeave(p);
|
|
|
|
/* If there are still other outstanding references to the shared-btree
|
|
** structure, return now. The remainder of this procedure cleans
|
|
** up the shared-btree.
|
|
*/
|
|
assert( p->wantToLock==0 && p->locked==0 );
|
|
if( !p->sharable || removeFromSharingList(pBt) ){
|
|
/* The pBt is no longer on the sharing list, so we can access
|
|
** it without having to hold the mutex.
|
|
**
|
|
** Clean out and delete the BtShared object.
|
|
*/
|
|
assert( !pBt->pCursor );
|
|
sqlite3PagerClose(pBt->pPager);
|
|
if( pBt->xFreeSchema && pBt->pSchema ){
|
|
pBt->xFreeSchema(pBt->pSchema);
|
|
}
|
|
sqlite3DbFree(0, pBt->pSchema);
|
|
freeTempSpace(pBt);
|
|
sqlite3_free(pBt);
|
|
}
|
|
|
|
#ifndef SQLITE_OMIT_SHARED_CACHE
|
|
assert( p->wantToLock==0 );
|
|
assert( p->locked==0 );
|
|
if( p->pPrev ) p->pPrev->pNext = p->pNext;
|
|
if( p->pNext ) p->pNext->pPrev = p->pPrev;
|
|
#endif
|
|
|
|
sqlite3_free(p);
|
|
return SQLITE_OK;
|
|
}
|
|
|
|
/*
|
|
** Change the limit on the number of pages allowed in the cache.
|
|
**
|
|
** The maximum number of cache pages is set to the absolute
|
|
** value of mxPage. If mxPage is negative, the pager will
|
|
** operate asynchronously - it will not stop to do fsync()s
|
|
** to insure data is written to the disk surface before
|
|
** continuing. Transactions still work if synchronous is off,
|
|
** and the database cannot be corrupted if this program
|
|
** crashes. But if the operating system crashes or there is
|
|
** an abrupt power failure when synchronous is off, the database
|
|
** could be left in an inconsistent and unrecoverable state.
|
|
** Synchronous is on by default so database corruption is not
|
|
** normally a worry.
|
|
*/
|
|
SQLITE_PRIVATE int sqlite3BtreeSetCacheSize(Btree *p, int mxPage){
|
|
BtShared *pBt = p->pBt;
|
|
assert( sqlite3_mutex_held(p->db->mutex) );
|
|
sqlite3BtreeEnter(p);
|
|
sqlite3PagerSetCachesize(pBt->pPager, mxPage);
|
|
sqlite3BtreeLeave(p);
|
|
return SQLITE_OK;
|
|
}
|
|
|
|
/*
|
|
** Change the way data is synced to disk in order to increase or decrease
|
|
** how well the database resists damage due to OS crashes and power
|
|
** failures. Level 1 is the same as asynchronous (no syncs() occur and
|
|
** there is a high probability of damage) Level 2 is the default. There
|
|
** is a very low but non-zero probability of damage. Level 3 reduces the
|
|
** probability of damage to near zero but with a write performance reduction.
|
|
*/
|
|
#ifndef SQLITE_OMIT_PAGER_PRAGMAS
|
|
SQLITE_PRIVATE int sqlite3BtreeSetSafetyLevel(
|
|
Btree *p, /* The btree to set the safety level on */
|
|
int level, /* PRAGMA synchronous. 1=OFF, 2=NORMAL, 3=FULL */
|
|
int fullSync, /* PRAGMA fullfsync. */
|
|
int ckptFullSync /* PRAGMA checkpoint_fullfync */
|
|
){
|
|
BtShared *pBt = p->pBt;
|
|
assert( sqlite3_mutex_held(p->db->mutex) );
|
|
assert( level>=1 && level<=3 );
|
|
sqlite3BtreeEnter(p);
|
|
sqlite3PagerSetSafetyLevel(pBt->pPager, level, fullSync, ckptFullSync);
|
|
sqlite3BtreeLeave(p);
|
|
return SQLITE_OK;
|
|
}
|
|
#endif
|
|
|
|
/*
|
|
** Return TRUE if the given btree is set to safety level 1. In other
|
|
** words, return TRUE if no sync() occurs on the disk files.
|
|
*/
|
|
SQLITE_PRIVATE int sqlite3BtreeSyncDisabled(Btree *p){
|
|
BtShared *pBt = p->pBt;
|
|
int rc;
|
|
assert( sqlite3_mutex_held(p->db->mutex) );
|
|
sqlite3BtreeEnter(p);
|
|
assert( pBt && pBt->pPager );
|
|
rc = sqlite3PagerNosync(pBt->pPager);
|
|
sqlite3BtreeLeave(p);
|
|
return rc;
|
|
}
|
|
|
|
#if !defined(SQLITE_OMIT_PAGER_PRAGMAS) || !defined(SQLITE_OMIT_VACUUM)
|
|
/*
|
|
** Change the default pages size and the number of reserved bytes per page.
|
|
** Or, if the page size has already been fixed, return SQLITE_READONLY
|
|
** without changing anything.
|
|
**
|
|
** The page size must be a power of 2 between 512 and 65536. If the page
|
|
** size supplied does not meet this constraint then the page size is not
|
|
** changed.
|
|
**
|
|
** Page sizes are constrained to be a power of two so that the region
|
|
** of the database file used for locking (beginning at PENDING_BYTE,
|
|
** the first byte past the 1GB boundary, 0x40000000) needs to occur
|
|
** at the beginning of a page.
|
|
**
|
|
** If parameter nReserve is less than zero, then the number of reserved
|
|
** bytes per page is left unchanged.
|
|
**
|
|
** If the iFix!=0 then the pageSizeFixed flag is set so that the page size
|
|
** and autovacuum mode can no longer be changed.
|
|
*/
|
|
SQLITE_PRIVATE int sqlite3BtreeSetPageSize(Btree *p, int pageSize, int nReserve, int iFix){
|
|
int rc = SQLITE_OK;
|
|
BtShared *pBt = p->pBt;
|
|
assert( nReserve>=-1 && nReserve<=255 );
|
|
sqlite3BtreeEnter(p);
|
|
if( pBt->pageSizeFixed ){
|
|
sqlite3BtreeLeave(p);
|
|
return SQLITE_READONLY;
|
|
}
|
|
if( nReserve<0 ){
|
|
nReserve = pBt->pageSize - pBt->usableSize;
|
|
}
|
|
assert( nReserve>=0 && nReserve<=255 );
|
|
if( pageSize>=512 && pageSize<=SQLITE_MAX_PAGE_SIZE &&
|
|
((pageSize-1)&pageSize)==0 ){
|
|
assert( (pageSize & 7)==0 );
|
|
assert( !pBt->pPage1 && !pBt->pCursor );
|
|
pBt->pageSize = (u32)pageSize;
|
|
freeTempSpace(pBt);
|
|
}
|
|
rc = sqlite3PagerSetPagesize(pBt->pPager, &pBt->pageSize, nReserve);
|
|
pBt->usableSize = pBt->pageSize - (u16)nReserve;
|
|
if( iFix ) pBt->pageSizeFixed = 1;
|
|
sqlite3BtreeLeave(p);
|
|
return rc;
|
|
}
|
|
|
|
/*
|
|
** Return the currently defined page size
|
|
*/
|
|
SQLITE_PRIVATE int sqlite3BtreeGetPageSize(Btree *p){
|
|
return p->pBt->pageSize;
|
|
}
|
|
|
|
/*
|
|
** Return the number of bytes of space at the end of every page that
|
|
** are intentually left unused. This is the "reserved" space that is
|
|
** sometimes used by extensions.
|
|
*/
|
|
SQLITE_PRIVATE int sqlite3BtreeGetReserve(Btree *p){
|
|
int n;
|
|
sqlite3BtreeEnter(p);
|
|
n = p->pBt->pageSize - p->pBt->usableSize;
|
|
sqlite3BtreeLeave(p);
|
|
return n;
|
|
}
|
|
|
|
/*
|
|
** Set the maximum page count for a database if mxPage is positive.
|
|
** No changes are made if mxPage is 0 or negative.
|
|
** Regardless of the value of mxPage, return the maximum page count.
|
|
*/
|
|
SQLITE_PRIVATE int sqlite3BtreeMaxPageCount(Btree *p, int mxPage){
|
|
int n;
|
|
sqlite3BtreeEnter(p);
|
|
n = sqlite3PagerMaxPageCount(p->pBt->pPager, mxPage);
|
|
sqlite3BtreeLeave(p);
|
|
return n;
|
|
}
|
|
|
|
/*
|
|
** Set the secureDelete flag if newFlag is 0 or 1. If newFlag is -1,
|
|
** then make no changes. Always return the value of the secureDelete
|
|
** setting after the change.
|
|
*/
|
|
SQLITE_PRIVATE int sqlite3BtreeSecureDelete(Btree *p, int newFlag){
|
|
int b;
|
|
if( p==0 ) return 0;
|
|
sqlite3BtreeEnter(p);
|
|
if( newFlag>=0 ){
|
|
p->pBt->secureDelete = (newFlag!=0) ? 1 : 0;
|
|
}
|
|
b = p->pBt->secureDelete;
|
|
sqlite3BtreeLeave(p);
|
|
return b;
|
|
}
|
|
#endif /* !defined(SQLITE_OMIT_PAGER_PRAGMAS) || !defined(SQLITE_OMIT_VACUUM) */
|
|
|
|
/*
|
|
** Change the 'auto-vacuum' property of the database. If the 'autoVacuum'
|
|
** parameter is non-zero, then auto-vacuum mode is enabled. If zero, it
|
|
** is disabled. The default value for the auto-vacuum property is
|
|
** determined by the SQLITE_DEFAULT_AUTOVACUUM macro.
|
|
*/
|
|
SQLITE_PRIVATE int sqlite3BtreeSetAutoVacuum(Btree *p, int autoVacuum){
|
|
#ifdef SQLITE_OMIT_AUTOVACUUM
|
|
return SQLITE_READONLY;
|
|
#else
|
|
BtShared *pBt = p->pBt;
|
|
int rc = SQLITE_OK;
|
|
u8 av = (u8)autoVacuum;
|
|
|
|
sqlite3BtreeEnter(p);
|
|
if( pBt->pageSizeFixed && (av ?1:0)!=pBt->autoVacuum ){
|
|
rc = SQLITE_READONLY;
|
|
}else{
|
|
pBt->autoVacuum = av ?1:0;
|
|
pBt->incrVacuum = av==2 ?1:0;
|
|
}
|
|
sqlite3BtreeLeave(p);
|
|
return rc;
|
|
#endif
|
|
}
|
|
|
|
/*
|
|
** Return the value of the 'auto-vacuum' property. If auto-vacuum is
|
|
** enabled 1 is returned. Otherwise 0.
|
|
*/
|
|
SQLITE_PRIVATE int sqlite3BtreeGetAutoVacuum(Btree *p){
|
|
#ifdef SQLITE_OMIT_AUTOVACUUM
|
|
return BTREE_AUTOVACUUM_NONE;
|
|
#else
|
|
int rc;
|
|
sqlite3BtreeEnter(p);
|
|
rc = (
|
|
(!p->pBt->autoVacuum)?BTREE_AUTOVACUUM_NONE:
|
|
(!p->pBt->incrVacuum)?BTREE_AUTOVACUUM_FULL:
|
|
BTREE_AUTOVACUUM_INCR
|
|
);
|
|
sqlite3BtreeLeave(p);
|
|
return rc;
|
|
#endif
|
|
}
|
|
|
|
|
|
/*
|
|
** Get a reference to pPage1 of the database file. This will
|
|
** also acquire a readlock on that file.
|
|
**
|
|
** SQLITE_OK is returned on success. If the file is not a
|
|
** well-formed database file, then SQLITE_CORRUPT is returned.
|
|
** SQLITE_BUSY is returned if the database is locked. SQLITE_NOMEM
|
|
** is returned if we run out of memory.
|
|
*/
|
|
static int lockBtree(BtShared *pBt){
|
|
int rc; /* Result code from subfunctions */
|
|
MemPage *pPage1; /* Page 1 of the database file */
|
|
int nPage; /* Number of pages in the database */
|
|
int nPageFile = 0; /* Number of pages in the database file */
|
|
int nPageHeader; /* Number of pages in the database according to hdr */
|
|
|
|
assert( sqlite3_mutex_held(pBt->mutex) );
|
|
assert( pBt->pPage1==0 );
|
|
rc = sqlite3PagerSharedLock(pBt->pPager);
|
|
if( rc!=SQLITE_OK ) return rc;
|
|
rc = btreeGetPage(pBt, 1, &pPage1, 0);
|
|
if( rc!=SQLITE_OK ) return rc;
|
|
|
|
/* Do some checking to help insure the file we opened really is
|
|
** a valid database file.
|
|
*/
|
|
nPage = nPageHeader = get4byte(28+(u8*)pPage1->aData);
|
|
sqlite3PagerPagecount(pBt->pPager, &nPageFile);
|
|
if( nPage==0 || memcmp(24+(u8*)pPage1->aData, 92+(u8*)pPage1->aData,4)!=0 ){
|
|
nPage = nPageFile;
|
|
}
|
|
if( nPage>0 ){
|
|
u32 pageSize;
|
|
u32 usableSize;
|
|
u8 *page1 = pPage1->aData;
|
|
rc = SQLITE_NOTADB;
|
|
if( memcmp(page1, zMagicHeader, 16)!=0 ){
|
|
goto page1_init_failed;
|
|
}
|
|
|
|
#ifdef SQLITE_OMIT_WAL
|
|
if( page1[18]>1 ){
|
|
pBt->readOnly = 1;
|
|
}
|
|
if( page1[19]>1 ){
|
|
goto page1_init_failed;
|
|
}
|
|
#else
|
|
if( page1[18]>2 ){
|
|
pBt->readOnly = 1;
|
|
}
|
|
if( page1[19]>2 ){
|
|
goto page1_init_failed;
|
|
}
|
|
|
|
/* If the write version is set to 2, this database should be accessed
|
|
** in WAL mode. If the log is not already open, open it now. Then
|
|
** return SQLITE_OK and return without populating BtShared.pPage1.
|
|
** The caller detects this and calls this function again. This is
|
|
** required as the version of page 1 currently in the page1 buffer
|
|
** may not be the latest version - there may be a newer one in the log
|
|
** file.
|
|
*/
|
|
if( page1[19]==2 && pBt->doNotUseWAL==0 ){
|
|
int isOpen = 0;
|
|
rc = sqlite3PagerOpenWal(pBt->pPager, &isOpen);
|
|
if( rc!=SQLITE_OK ){
|
|
goto page1_init_failed;
|
|
}else if( isOpen==0 ){
|
|
releasePage(pPage1);
|
|
return SQLITE_OK;
|
|
}
|
|
rc = SQLITE_NOTADB;
|
|
}
|
|
#endif
|
|
|
|
/* The maximum embedded fraction must be exactly 25%. And the minimum
|
|
** embedded fraction must be 12.5% for both leaf-data and non-leaf-data.
|
|
** The original design allowed these amounts to vary, but as of
|
|
** version 3.6.0, we require them to be fixed.
|
|
*/
|
|
if( memcmp(&page1[21], "\100\040\040",3)!=0 ){
|
|
goto page1_init_failed;
|
|
}
|
|
pageSize = (page1[16]<<8) | (page1[17]<<16);
|
|
if( ((pageSize-1)&pageSize)!=0
|
|
|| pageSize>SQLITE_MAX_PAGE_SIZE
|
|
|| pageSize<=256
|
|
){
|
|
goto page1_init_failed;
|
|
}
|
|
assert( (pageSize & 7)==0 );
|
|
usableSize = pageSize - page1[20];
|
|
if( (u32)pageSize!=pBt->pageSize || (u32)usableSize!=pBt->usableSize){
|
|
/* After reading the first page of the database assuming a page size
|
|
** of BtShared.pageSize, we have discovered that the page-size is
|
|
** actually pageSize OR that the reserveSize (and therefore usableSize)
|
|
** previously read from the potentially corrupt database header was wrong.
|
|
** Set the new values, unlock the database, leave pBt->pPage1 at
|
|
** zero and return SQLITE_OK. The caller will call this function
|
|
** again with the correct page-size.
|
|
*/
|
|
releasePage(pPage1);
|
|
pBt->usableSize = usableSize;
|
|
pBt->pageSize = pageSize;
|
|
freeTempSpace(pBt);
|
|
rc = sqlite3PagerSetPagesize(pBt->pPager, &pBt->pageSize,
|
|
pageSize-usableSize);
|
|
return rc;
|
|
}
|
|
if( (pBt->db->flags & SQLITE_RecoveryMode)==0 && nPage>nPageFile ){
|
|
rc = SQLITE_CORRUPT_BKPT;
|
|
goto page1_init_failed;
|
|
}
|
|
if( usableSize<480 ){
|
|
goto page1_init_failed;
|
|
}
|
|
pBt->pageSize = pageSize;
|
|
pBt->usableSize = usableSize;
|
|
#ifndef SQLITE_OMIT_AUTOVACUUM
|
|
pBt->autoVacuum = (get4byte(&page1[36 + 4*4])?1:0);
|
|
pBt->incrVacuum = (get4byte(&page1[36 + 7*4])?1:0);
|
|
#endif
|
|
}
|
|
|
|
/* maxLocal is the maximum amount of payload to store locally for
|
|
** a cell. Make sure it is small enough so that at least minFanout
|
|
** cells can will fit on one page. We assume a 10-byte page header.
|
|
** Besides the payload, the cell must store:
|
|
** 2-byte pointer to the cell
|
|
** 4-byte child pointer
|
|
** 9-byte nKey value
|
|
** 4-byte nData value
|
|
** 4-byte overflow page pointer
|
|
** So a cell consists of a 2-byte pointer, a header which is as much as
|
|
** 17 bytes long, 0 to N bytes of payload, and an optional 4 byte overflow
|
|
** page pointer.
|
|
*/
|
|
pBt->maxLocal = (u16)((pBt->usableSize-12)*64/255 - 23);
|
|
pBt->minLocal = (u16)((pBt->usableSize-12)*32/255 - 23);
|
|
pBt->maxLeaf = (u16)(pBt->usableSize - 35);
|
|
pBt->minLeaf = (u16)((pBt->usableSize-12)*32/255 - 23);
|
|
assert( pBt->maxLeaf + 23 <= MX_CELL_SIZE(pBt) );
|
|
pBt->pPage1 = pPage1;
|
|
pBt->nPage = nPage;
|
|
return SQLITE_OK;
|
|
|
|
page1_init_failed:
|
|
releasePage(pPage1);
|
|
pBt->pPage1 = 0;
|
|
return rc;
|
|
}
|
|
|
|
/*
|
|
** If there are no outstanding cursors and we are not in the middle
|
|
** of a transaction but there is a read lock on the database, then
|
|
** this routine unrefs the first page of the database file which
|
|
** has the effect of releasing the read lock.
|
|
**
|
|
** If there is a transaction in progress, this routine is a no-op.
|
|
*/
|
|
static void unlockBtreeIfUnused(BtShared *pBt){
|
|
assert( sqlite3_mutex_held(pBt->mutex) );
|
|
assert( pBt->pCursor==0 || pBt->inTransaction>TRANS_NONE );
|
|
if( pBt->inTransaction==TRANS_NONE && pBt->pPage1!=0 ){
|
|
assert( pBt->pPage1->aData );
|
|
assert( sqlite3PagerRefcount(pBt->pPager)==1 );
|
|
assert( pBt->pPage1->aData );
|
|
releasePage(pBt->pPage1);
|
|
pBt->pPage1 = 0;
|
|
}
|
|
}
|
|
|
|
/*
|
|
** If pBt points to an empty file then convert that empty file
|
|
** into a new empty database by initializing the first page of
|
|
** the database.
|
|
*/
|
|
static int newDatabase(BtShared *pBt){
|
|
MemPage *pP1;
|
|
unsigned char *data;
|
|
int rc;
|
|
|
|
assert( sqlite3_mutex_held(pBt->mutex) );
|
|
if( pBt->nPage>0 ){
|
|
return SQLITE_OK;
|
|
}
|
|
pP1 = pBt->pPage1;
|
|
assert( pP1!=0 );
|
|
data = pP1->aData;
|
|
rc = sqlite3PagerWrite(pP1->pDbPage);
|
|
if( rc ) return rc;
|
|
memcpy(data, zMagicHeader, sizeof(zMagicHeader));
|
|
assert( sizeof(zMagicHeader)==16 );
|
|
data[16] = (u8)((pBt->pageSize>>8)&0xff);
|
|
data[17] = (u8)((pBt->pageSize>>16)&0xff);
|
|
data[18] = 1;
|
|
data[19] = 1;
|
|
assert( pBt->usableSize<=pBt->pageSize && pBt->usableSize+255>=pBt->pageSize);
|
|
data[20] = (u8)(pBt->pageSize - pBt->usableSize);
|
|
data[21] = 64;
|
|
data[22] = 32;
|
|
data[23] = 32;
|
|
memset(&data[24], 0, 100-24);
|
|
zeroPage(pP1, PTF_INTKEY|PTF_LEAF|PTF_LEAFDATA );
|
|
pBt->pageSizeFixed = 1;
|
|
#ifndef SQLITE_OMIT_AUTOVACUUM
|
|
assert( pBt->autoVacuum==1 || pBt->autoVacuum==0 );
|
|
assert( pBt->incrVacuum==1 || pBt->incrVacuum==0 );
|
|
put4byte(&data[36 + 4*4], pBt->autoVacuum);
|
|
put4byte(&data[36 + 7*4], pBt->incrVacuum);
|
|
#endif
|
|
pBt->nPage = 1;
|
|
data[31] = 1;
|
|
return SQLITE_OK;
|
|
}
|
|
|
|
/*
|
|
** Attempt to start a new transaction. A write-transaction
|
|
** is started if the second argument is nonzero, otherwise a read-
|
|
** transaction. If the second argument is 2 or more and exclusive
|
|
** transaction is started, meaning that no other process is allowed
|
|
** to access the database. A preexisting transaction may not be
|
|
** upgraded to exclusive by calling this routine a second time - the
|
|
** exclusivity flag only works for a new transaction.
|
|
**
|
|
** A write-transaction must be started before attempting any
|
|
** changes to the database. None of the following routines
|
|
** will work unless a transaction is started first:
|
|
**
|
|
** sqlite3BtreeCreateTable()
|
|
** sqlite3BtreeCreateIndex()
|
|
** sqlite3BtreeClearTable()
|
|
** sqlite3BtreeDropTable()
|
|
** sqlite3BtreeInsert()
|
|
** sqlite3BtreeDelete()
|
|
** sqlite3BtreeUpdateMeta()
|
|
**
|
|
** If an initial attempt to acquire the lock fails because of lock contention
|
|
** and the database was previously unlocked, then invoke the busy handler
|
|
** if there is one. But if there was previously a read-lock, do not
|
|
** invoke the busy handler - just return SQLITE_BUSY. SQLITE_BUSY is
|
|
** returned when there is already a read-lock in order to avoid a deadlock.
|
|
**
|
|
** Suppose there are two processes A and B. A has a read lock and B has
|
|
** a reserved lock. B tries to promote to exclusive but is blocked because
|
|
** of A's read lock. A tries to promote to reserved but is blocked by B.
|
|
** One or the other of the two processes must give way or there can be
|
|
** no progress. By returning SQLITE_BUSY and not invoking the busy callback
|
|
** when A already has a read lock, we encourage A to give up and let B
|
|
** proceed.
|
|
*/
|
|
SQLITE_PRIVATE int sqlite3BtreeBeginTrans(Btree *p, int wrflag){
|
|
#ifndef SQLITE_OMIT_SHARED_CACHE
|
|
sqlite3 *pBlock = 0;
|
|
#endif
|
|
BtShared *pBt = p->pBt;
|
|
int rc = SQLITE_OK;
|
|
|
|
sqlite3BtreeEnter(p);
|
|
btreeIntegrity(p);
|
|
|
|
/* If the btree is already in a write-transaction, or it
|
|
** is already in a read-transaction and a read-transaction
|
|
** is requested, this is a no-op.
|
|
*/
|
|
if( p->inTrans==TRANS_WRITE || (p->inTrans==TRANS_READ && !wrflag) ){
|
|
goto trans_begun;
|
|
}
|
|
|
|
/* Write transactions are not possible on a read-only database */
|
|
if( pBt->readOnly && wrflag ){
|
|
rc = SQLITE_READONLY;
|
|
goto trans_begun;
|
|
}
|
|
|
|
#ifndef SQLITE_OMIT_SHARED_CACHE
|
|
/* If another database handle has already opened a write transaction
|
|
** on this shared-btree structure and a second write transaction is
|
|
** requested, return SQLITE_LOCKED.
|
|
*/
|
|
if( (wrflag && pBt->inTransaction==TRANS_WRITE) || pBt->isPending ){
|
|
pBlock = pBt->pWriter->db;
|
|
}else if( wrflag>1 ){
|
|
BtLock *pIter;
|
|
for(pIter=pBt->pLock; pIter; pIter=pIter->pNext){
|
|
if( pIter->pBtree!=p ){
|
|
pBlock = pIter->pBtree->db;
|
|
break;
|
|
}
|
|
}
|
|
}
|
|
if( pBlock ){
|
|
sqlite3ConnectionBlocked(p->db, pBlock);
|
|
rc = SQLITE_LOCKED_SHAREDCACHE;
|
|
goto trans_begun;
|
|
}
|
|
#endif
|
|
|
|
/* Any read-only or read-write transaction implies a read-lock on
|
|
** page 1. So if some other shared-cache client already has a write-lock
|
|
** on page 1, the transaction cannot be opened. */
|
|
rc = querySharedCacheTableLock(p, MASTER_ROOT, READ_LOCK);
|
|
if( SQLITE_OK!=rc ) goto trans_begun;
|
|
|
|
pBt->initiallyEmpty = (u8)(pBt->nPage==0);
|
|
do {
|
|
/* Call lockBtree() until either pBt->pPage1 is populated or
|
|
** lockBtree() returns something other than SQLITE_OK. lockBtree()
|
|
** may return SQLITE_OK but leave pBt->pPage1 set to 0 if after
|
|
** reading page 1 it discovers that the page-size of the database
|
|
** file is not pBt->pageSize. In this case lockBtree() will update
|
|
** pBt->pageSize to the page-size of the file on disk.
|
|
*/
|
|
while( pBt->pPage1==0 && SQLITE_OK==(rc = lockBtree(pBt)) );
|
|
|
|
if( rc==SQLITE_OK && wrflag ){
|
|
if( pBt->readOnly ){
|
|
rc = SQLITE_READONLY;
|
|
}else{
|
|
rc = sqlite3PagerBegin(pBt->pPager,wrflag>1,sqlite3TempInMemory(p->db));
|
|
if( rc==SQLITE_OK ){
|
|
rc = newDatabase(pBt);
|
|
}
|
|
}
|
|
}
|
|
|
|
if( rc!=SQLITE_OK ){
|
|
unlockBtreeIfUnused(pBt);
|
|
}
|
|
}while( (rc&0xFF)==SQLITE_BUSY && pBt->inTransaction==TRANS_NONE &&
|
|
btreeInvokeBusyHandler(pBt) );
|
|
|
|
if( rc==SQLITE_OK ){
|
|
if( p->inTrans==TRANS_NONE ){
|
|
pBt->nTransaction++;
|
|
#ifndef SQLITE_OMIT_SHARED_CACHE
|
|
if( p->sharable ){
|
|
assert( p->lock.pBtree==p && p->lock.iTable==1 );
|
|
p->lock.eLock = READ_LOCK;
|
|
p->lock.pNext = pBt->pLock;
|
|
pBt->pLock = &p->lock;
|
|
}
|
|
#endif
|
|
}
|
|
p->inTrans = (wrflag?TRANS_WRITE:TRANS_READ);
|
|
if( p->inTrans>pBt->inTransaction ){
|
|
pBt->inTransaction = p->inTrans;
|
|
}
|
|
if( wrflag ){
|
|
MemPage *pPage1 = pBt->pPage1;
|
|
#ifndef SQLITE_OMIT_SHARED_CACHE
|
|
assert( !pBt->pWriter );
|
|
pBt->pWriter = p;
|
|
pBt->isExclusive = (u8)(wrflag>1);
|
|
#endif
|
|
|
|
/* If the db-size header field is incorrect (as it may be if an old
|
|
** client has been writing the database file), update it now. Doing
|
|
** this sooner rather than later means the database size can safely
|
|
** re-read the database size from page 1 if a savepoint or transaction
|
|
** rollback occurs within the transaction.
|
|
*/
|
|
if( pBt->nPage!=get4byte(&pPage1->aData[28]) ){
|
|
rc = sqlite3PagerWrite(pPage1->pDbPage);
|
|
if( rc==SQLITE_OK ){
|
|
put4byte(&pPage1->aData[28], pBt->nPage);
|
|
}
|
|
}
|
|
}
|
|
}
|
|
|
|
|
|
trans_begun:
|
|
if( rc==SQLITE_OK && wrflag ){
|
|
/* This call makes sure that the pager has the correct number of
|
|
** open savepoints. If the second parameter is greater than 0 and
|
|
** the sub-journal is not already open, then it will be opened here.
|
|
*/
|
|
rc = sqlite3PagerOpenSavepoint(pBt->pPager, p->db->nSavepoint);
|
|
}
|
|
|
|
btreeIntegrity(p);
|
|
sqlite3BtreeLeave(p);
|
|
return rc;
|
|
}
|
|
|
|
#ifndef SQLITE_OMIT_AUTOVACUUM
|
|
|
|
/*
|
|
** Set the pointer-map entries for all children of page pPage. Also, if
|
|
** pPage contains cells that point to overflow pages, set the pointer
|
|
** map entries for the overflow pages as well.
|
|
*/
|
|
static int setChildPtrmaps(MemPage *pPage){
|
|
int i; /* Counter variable */
|
|
int nCell; /* Number of cells in page pPage */
|
|
int rc; /* Return code */
|
|
BtShared *pBt = pPage->pBt;
|
|
u8 isInitOrig = pPage->isInit;
|
|
Pgno pgno = pPage->pgno;
|
|
|
|
assert( sqlite3_mutex_held(pPage->pBt->mutex) );
|
|
rc = btreeInitPage(pPage);
|
|
if( rc!=SQLITE_OK ){
|
|
goto set_child_ptrmaps_out;
|
|
}
|
|
nCell = pPage->nCell;
|
|
|
|
for(i=0; i<nCell; i++){
|
|
u8 *pCell = findCell(pPage, i);
|
|
|
|
ptrmapPutOvflPtr(pPage, pCell, &rc);
|
|
|
|
if( !pPage->leaf ){
|
|
Pgno childPgno = get4byte(pCell);
|
|
ptrmapPut(pBt, childPgno, PTRMAP_BTREE, pgno, &rc);
|
|
}
|
|
}
|
|
|
|
if( !pPage->leaf ){
|
|
Pgno childPgno = get4byte(&pPage->aData[pPage->hdrOffset+8]);
|
|
ptrmapPut(pBt, childPgno, PTRMAP_BTREE, pgno, &rc);
|
|
}
|
|
|
|
set_child_ptrmaps_out:
|
|
pPage->isInit = isInitOrig;
|
|
return rc;
|
|
}
|
|
|
|
/*
|
|
** Somewhere on pPage is a pointer to page iFrom. Modify this pointer so
|
|
** that it points to iTo. Parameter eType describes the type of pointer to
|
|
** be modified, as follows:
|
|
**
|
|
** PTRMAP_BTREE: pPage is a btree-page. The pointer points at a child
|
|
** page of pPage.
|
|
**
|
|
** PTRMAP_OVERFLOW1: pPage is a btree-page. The pointer points at an overflow
|
|
** page pointed to by one of the cells on pPage.
|
|
**
|
|
** PTRMAP_OVERFLOW2: pPage is an overflow-page. The pointer points at the next
|
|
** overflow page in the list.
|
|
*/
|
|
static int modifyPagePointer(MemPage *pPage, Pgno iFrom, Pgno iTo, u8 eType){
|
|
assert( sqlite3_mutex_held(pPage->pBt->mutex) );
|
|
assert( sqlite3PagerIswriteable(pPage->pDbPage) );
|
|
if( eType==PTRMAP_OVERFLOW2 ){
|
|
/* The pointer is always the first 4 bytes of the page in this case. */
|
|
if( get4byte(pPage->aData)!=iFrom ){
|
|
return SQLITE_CORRUPT_BKPT;
|
|
}
|
|
put4byte(pPage->aData, iTo);
|
|
}else{
|
|
u8 isInitOrig = pPage->isInit;
|
|
int i;
|
|
int nCell;
|
|
|
|
btreeInitPage(pPage);
|
|
nCell = pPage->nCell;
|
|
|
|
for(i=0; i<nCell; i++){
|
|
u8 *pCell = findCell(pPage, i);
|
|
if( eType==PTRMAP_OVERFLOW1 ){
|
|
CellInfo info;
|
|
btreeParseCellPtr(pPage, pCell, &info);
|
|
if( info.iOverflow ){
|
|
if( iFrom==get4byte(&pCell[info.iOverflow]) ){
|
|
put4byte(&pCell[info.iOverflow], iTo);
|
|
break;
|
|
}
|
|
}
|
|
}else{
|
|
if( get4byte(pCell)==iFrom ){
|
|
put4byte(pCell, iTo);
|
|
break;
|
|
}
|
|
}
|
|
}
|
|
|
|
if( i==nCell ){
|
|
if( eType!=PTRMAP_BTREE ||
|
|
get4byte(&pPage->aData[pPage->hdrOffset+8])!=iFrom ){
|
|
return SQLITE_CORRUPT_BKPT;
|
|
}
|
|
put4byte(&pPage->aData[pPage->hdrOffset+8], iTo);
|
|
}
|
|
|
|
pPage->isInit = isInitOrig;
|
|
}
|
|
return SQLITE_OK;
|
|
}
|
|
|
|
|
|
/*
|
|
** Move the open database page pDbPage to location iFreePage in the
|
|
** database. The pDbPage reference remains valid.
|
|
**
|
|
** The isCommit flag indicates that there is no need to remember that
|
|
** the journal needs to be sync()ed before database page pDbPage->pgno
|
|
** can be written to. The caller has already promised not to write to that
|
|
** page.
|
|
*/
|
|
static int relocatePage(
|
|
BtShared *pBt, /* Btree */
|
|
MemPage *pDbPage, /* Open page to move */
|
|
u8 eType, /* Pointer map 'type' entry for pDbPage */
|
|
Pgno iPtrPage, /* Pointer map 'page-no' entry for pDbPage */
|
|
Pgno iFreePage, /* The location to move pDbPage to */
|
|
int isCommit /* isCommit flag passed to sqlite3PagerMovepage */
|
|
){
|
|
MemPage *pPtrPage; /* The page that contains a pointer to pDbPage */
|
|
Pgno iDbPage = pDbPage->pgno;
|
|
Pager *pPager = pBt->pPager;
|
|
int rc;
|
|
|
|
assert( eType==PTRMAP_OVERFLOW2 || eType==PTRMAP_OVERFLOW1 ||
|
|
eType==PTRMAP_BTREE || eType==PTRMAP_ROOTPAGE );
|
|
assert( sqlite3_mutex_held(pBt->mutex) );
|
|
assert( pDbPage->pBt==pBt );
|
|
|
|
/* Move page iDbPage from its current location to page number iFreePage */
|
|
TRACE(("AUTOVACUUM: Moving %d to free page %d (ptr page %d type %d)\n",
|
|
iDbPage, iFreePage, iPtrPage, eType));
|
|
rc = sqlite3PagerMovepage(pPager, pDbPage->pDbPage, iFreePage, isCommit);
|
|
if( rc!=SQLITE_OK ){
|
|
return rc;
|
|
}
|
|
pDbPage->pgno = iFreePage;
|
|
|
|
/* If pDbPage was a btree-page, then it may have child pages and/or cells
|
|
** that point to overflow pages. The pointer map entries for all these
|
|
** pages need to be changed.
|
|
**
|
|
** If pDbPage is an overflow page, then the first 4 bytes may store a
|
|
** pointer to a subsequent overflow page. If this is the case, then
|
|
** the pointer map needs to be updated for the subsequent overflow page.
|
|
*/
|
|
if( eType==PTRMAP_BTREE || eType==PTRMAP_ROOTPAGE ){
|
|
rc = setChildPtrmaps(pDbPage);
|
|
if( rc!=SQLITE_OK ){
|
|
return rc;
|
|
}
|
|
}else{
|
|
Pgno nextOvfl = get4byte(pDbPage->aData);
|
|
if( nextOvfl!=0 ){
|
|
ptrmapPut(pBt, nextOvfl, PTRMAP_OVERFLOW2, iFreePage, &rc);
|
|
if( rc!=SQLITE_OK ){
|
|
return rc;
|
|
}
|
|
}
|
|
}
|
|
|
|
/* Fix the database pointer on page iPtrPage that pointed at iDbPage so
|
|
** that it points at iFreePage. Also fix the pointer map entry for
|
|
** iPtrPage.
|
|
*/
|
|
if( eType!=PTRMAP_ROOTPAGE ){
|
|
rc = btreeGetPage(pBt, iPtrPage, &pPtrPage, 0);
|
|
if( rc!=SQLITE_OK ){
|
|
return rc;
|
|
}
|
|
rc = sqlite3PagerWrite(pPtrPage->pDbPage);
|
|
if( rc!=SQLITE_OK ){
|
|
releasePage(pPtrPage);
|
|
return rc;
|
|
}
|
|
rc = modifyPagePointer(pPtrPage, iDbPage, iFreePage, eType);
|
|
releasePage(pPtrPage);
|
|
if( rc==SQLITE_OK ){
|
|
ptrmapPut(pBt, iFreePage, eType, iPtrPage, &rc);
|
|
}
|
|
}
|
|
return rc;
|
|
}
|
|
|
|
/* Forward declaration required by incrVacuumStep(). */
|
|
static int allocateBtreePage(BtShared *, MemPage **, Pgno *, Pgno, u8);
|
|
|
|
/*
|
|
** Perform a single step of an incremental-vacuum. If successful,
|
|
** return SQLITE_OK. If there is no work to do (and therefore no
|
|
** point in calling this function again), return SQLITE_DONE.
|
|
**
|
|
** More specificly, this function attempts to re-organize the
|
|
** database so that the last page of the file currently in use
|
|
** is no longer in use.
|
|
**
|
|
** If the nFin parameter is non-zero, this function assumes
|
|
** that the caller will keep calling incrVacuumStep() until
|
|
** it returns SQLITE_DONE or an error, and that nFin is the
|
|
** number of pages the database file will contain after this
|
|
** process is complete. If nFin is zero, it is assumed that
|
|
** incrVacuumStep() will be called a finite amount of times
|
|
** which may or may not empty the freelist. A full autovacuum
|
|
** has nFin>0. A "PRAGMA incremental_vacuum" has nFin==0.
|
|
*/
|
|
static int incrVacuumStep(BtShared *pBt, Pgno nFin, Pgno iLastPg){
|
|
Pgno nFreeList; /* Number of pages still on the free-list */
|
|
int rc;
|
|
|
|
assert( sqlite3_mutex_held(pBt->mutex) );
|
|
assert( iLastPg>nFin );
|
|
|
|
if( !PTRMAP_ISPAGE(pBt, iLastPg) && iLastPg!=PENDING_BYTE_PAGE(pBt) ){
|
|
u8 eType;
|
|
Pgno iPtrPage;
|
|
|
|
nFreeList = get4byte(&pBt->pPage1->aData[36]);
|
|
if( nFreeList==0 ){
|
|
return SQLITE_DONE;
|
|
}
|
|
|
|
rc = ptrmapGet(pBt, iLastPg, &eType, &iPtrPage);
|
|
if( rc!=SQLITE_OK ){
|
|
return rc;
|
|
}
|
|
if (eType==PTRMAP_LAZYFREE)
|
|
return SQLITE_DONE;
|
|
if( eType==PTRMAP_ROOTPAGE ){
|
|
return SQLITE_CORRUPT_BKPT;
|
|
}
|
|
|
|
if( eType == PTRMAP_FREELEAF ){
|
|
/* We are just going to truncate the file to remove this free page.
|
|
** We leave this page in the free list to be removed on a subsequent
|
|
** call to allocate.
|
|
*/
|
|
rc = sqlite3PagerWrite(pBt->pPage1->pDbPage);
|
|
if( rc!=SQLITE_OK ){
|
|
return rc;
|
|
}
|
|
|
|
put4byte(&pBt->pPage1->aData[36], nFreeList-1);
|
|
|
|
// Mark the last page as writable since we are about to truncate it
|
|
MemPage *pFreeLeaf;
|
|
rc = btreeGetPage(pBt, iLastPg, &pFreeLeaf, 0);
|
|
if( rc != SQLITE_OK ){
|
|
return rc;
|
|
}
|
|
|
|
rc = sqlite3PagerWrite(pFreeLeaf->pDbPage);
|
|
releasePage(pFreeLeaf);
|
|
if( rc != SQLITE_OK ){
|
|
return rc;
|
|
}
|
|
}
|
|
else if( eType==PTRMAP_FREEPAGE ){
|
|
if( nFin==0 ){
|
|
/* Remove the page from the files free-list. This is not required
|
|
** if nFin is non-zero. In that case, the free-list will be
|
|
** truncated to zero after this function returns, so it doesn't
|
|
** matter if it still contains some garbage entries.
|
|
*/
|
|
Pgno iFreePg;
|
|
MemPage *pFreePg;
|
|
rc = allocateBtreePage(pBt, &pFreePg, &iFreePg, iLastPg, 1);
|
|
if( rc!=SQLITE_OK ){
|
|
return rc;
|
|
}
|
|
assert( iFreePg==iLastPg );
|
|
releasePage(pFreePg);
|
|
}
|
|
} else {
|
|
Pgno iFreePg; /* Index of free page to move pLastPg to */
|
|
MemPage *pLastPg;
|
|
|
|
rc = btreeGetPage(pBt, iLastPg, &pLastPg, 0);
|
|
if( rc!=SQLITE_OK ){
|
|
return rc;
|
|
}
|
|
|
|
/* If nFin is zero, this loop runs exactly once and page pLastPg
|
|
** is swapped with the first free page pulled off the free list.
|
|
**
|
|
** On the other hand, if nFin is greater than zero, then keep
|
|
** looping until a free-page located within the first nFin pages
|
|
** of the file is found.
|
|
*/
|
|
do {
|
|
MemPage *pFreePg;
|
|
rc = allocateBtreePage(pBt, &pFreePg, &iFreePg, 0, 0);
|
|
if( rc!=SQLITE_OK ){
|
|
releasePage(pLastPg);
|
|
return rc;
|
|
}
|
|
releasePage(pFreePg);
|
|
}while( nFin!=0 && iFreePg>nFin );
|
|
assert( iFreePg<iLastPg );
|
|
|
|
rc = sqlite3PagerWrite(pLastPg->pDbPage);
|
|
if( rc==SQLITE_OK ){
|
|
rc = relocatePage(pBt, pLastPg, eType, iPtrPage, iFreePg, nFin!=0);
|
|
}
|
|
releasePage(pLastPg);
|
|
if( rc!=SQLITE_OK ){
|
|
return rc;
|
|
}
|
|
}
|
|
}
|
|
|
|
if( nFin==0 ){
|
|
iLastPg--;
|
|
while( iLastPg==PENDING_BYTE_PAGE(pBt)||PTRMAP_ISPAGE(pBt, iLastPg) ){
|
|
if( PTRMAP_ISPAGE(pBt, iLastPg) ){
|
|
MemPage *pPg;
|
|
rc = btreeGetPage(pBt, iLastPg, &pPg, 0);
|
|
if( rc!=SQLITE_OK ){
|
|
return rc;
|
|
}
|
|
rc = sqlite3PagerWrite(pPg->pDbPage);
|
|
releasePage(pPg);
|
|
if( rc!=SQLITE_OK ){
|
|
return rc;
|
|
}
|
|
}
|
|
iLastPg--;
|
|
}
|
|
sqlite3PagerTruncateImage(pBt->pPager, iLastPg);
|
|
pBt->nPage = iLastPg;
|
|
}
|
|
return SQLITE_OK;
|
|
}
|
|
|
|
/*
|
|
** A write-transaction must be opened before calling this function.
|
|
** It performs a single unit of work towards an incremental vacuum.
|
|
**
|
|
** If the incremental vacuum is finished after this function has run,
|
|
** SQLITE_DONE is returned. If it is not finished, but no error occurred,
|
|
** SQLITE_OK is returned. Otherwise an SQLite error code.
|
|
*/
|
|
SQLITE_PRIVATE int sqlite3BtreeIncrVacuum(Btree *p){
|
|
int rc;
|
|
BtShared *pBt = p->pBt;
|
|
|
|
sqlite3BtreeEnter(p);
|
|
assert( pBt->inTransaction==TRANS_WRITE && p->inTrans==TRANS_WRITE );
|
|
if( !pBt->autoVacuum ){
|
|
rc = SQLITE_DONE;
|
|
}else{
|
|
invalidateAllOverflowCache(pBt);
|
|
rc = incrVacuumStep(pBt, 0, btreePagecount(pBt));
|
|
if( rc==SQLITE_OK ){
|
|
rc = sqlite3PagerWrite(pBt->pPage1->pDbPage);
|
|
put4byte(&pBt->pPage1->aData[28], pBt->nPage);
|
|
}
|
|
}
|
|
sqlite3BtreeLeave(p);
|
|
return rc;
|
|
}
|
|
|
|
/*
|
|
** This routine is called prior to sqlite3PagerCommit when a transaction
|
|
** is commited for an auto-vacuum database.
|
|
**
|
|
** If SQLITE_OK is returned, then *pnTrunc is set to the number of pages
|
|
** the database file should be truncated to during the commit process.
|
|
** i.e. the database has been reorganized so that only the first *pnTrunc
|
|
** pages are in use.
|
|
*/
|
|
static int autoVacuumCommit(BtShared *pBt){
|
|
int rc = SQLITE_OK;
|
|
Pager *pPager = pBt->pPager;
|
|
VVA_ONLY( int nRef = sqlite3PagerRefcount(pPager) );
|
|
|
|
assert( sqlite3_mutex_held(pBt->mutex) );
|
|
invalidateAllOverflowCache(pBt);
|
|
assert(pBt->autoVacuum);
|
|
if( !pBt->incrVacuum ){
|
|
Pgno nFin; /* Number of pages in database after autovacuuming */
|
|
Pgno nFree; /* Number of pages on the freelist initially */
|
|
Pgno nPtrmap; /* Number of PtrMap pages to be freed */
|
|
Pgno iFree; /* The next page to be freed */
|
|
int nEntry; /* Number of entries on one ptrmap page */
|
|
Pgno nOrig; /* Database size before freeing */
|
|
|
|
nOrig = btreePagecount(pBt);
|
|
if( PTRMAP_ISPAGE(pBt, nOrig) || nOrig==PENDING_BYTE_PAGE(pBt) ){
|
|
/* It is not possible to create a database for which the final page
|
|
** is either a pointer-map page or the pending-byte page. If one
|
|
** is encountered, this indicates corruption.
|
|
*/
|
|
return SQLITE_CORRUPT_BKPT;
|
|
}
|
|
|
|
nFree = get4byte(&pBt->pPage1->aData[36]);
|
|
nEntry = pBt->usableSize/5;
|
|
nPtrmap = (nFree-nOrig+PTRMAP_PAGENO(pBt, nOrig)+nEntry)/nEntry;
|
|
nFin = nOrig - nFree - nPtrmap;
|
|
if( nOrig>PENDING_BYTE_PAGE(pBt) && nFin<PENDING_BYTE_PAGE(pBt) ){
|
|
nFin--;
|
|
}
|
|
while( PTRMAP_ISPAGE(pBt, nFin) || nFin==PENDING_BYTE_PAGE(pBt) ){
|
|
nFin--;
|
|
}
|
|
if( nFin>nOrig ) return SQLITE_CORRUPT_BKPT;
|
|
|
|
for(iFree=nOrig; iFree>nFin && rc==SQLITE_OK; iFree--){
|
|
rc = incrVacuumStep(pBt, nFin, iFree);
|
|
}
|
|
if( (rc==SQLITE_DONE || rc==SQLITE_OK) && nFree>0 ){
|
|
rc = sqlite3PagerWrite(pBt->pPage1->pDbPage);
|
|
put4byte(&pBt->pPage1->aData[32], 0);
|
|
put4byte(&pBt->pPage1->aData[36], 0);
|
|
put4byte(&pBt->pPage1->aData[28], nFin);
|
|
sqlite3PagerTruncateImage(pBt->pPager, nFin);
|
|
pBt->nPage = nFin;
|
|
}
|
|
if( rc!=SQLITE_OK ){
|
|
sqlite3PagerRollback(pPager);
|
|
}
|
|
}
|
|
|
|
assert( nRef==sqlite3PagerRefcount(pPager) );
|
|
return rc;
|
|
}
|
|
|
|
#else /* ifndef SQLITE_OMIT_AUTOVACUUM */
|
|
# define setChildPtrmaps(x) SQLITE_OK
|
|
#endif
|
|
|
|
/*
|
|
** This routine does the first phase of a two-phase commit. This routine
|
|
** causes a rollback journal to be created (if it does not already exist)
|
|
** and populated with enough information so that if a power loss occurs
|
|
** the database can be restored to its original state by playing back
|
|
** the journal. Then the contents of the journal are flushed out to
|
|
** the disk. After the journal is safely on oxide, the changes to the
|
|
** database are written into the database file and flushed to oxide.
|
|
** At the end of this call, the rollback journal still exists on the
|
|
** disk and we are still holding all locks, so the transaction has not
|
|
** committed. See sqlite3BtreeCommitPhaseTwo() for the second phase of the
|
|
** commit process.
|
|
**
|
|
** This call is a no-op if no write-transaction is currently active on pBt.
|
|
**
|
|
** Otherwise, sync the database file for the btree pBt. zMaster points to
|
|
** the name of a master journal file that should be written into the
|
|
** individual journal file, or is NULL, indicating no master journal file
|
|
** (single database transaction).
|
|
**
|
|
** When this is called, the master journal should already have been
|
|
** created, populated with this journal pointer and synced to disk.
|
|
**
|
|
** Once this is routine has returned, the only thing required to commit
|
|
** the write-transaction for this database file is to delete the journal.
|
|
*/
|
|
SQLITE_PRIVATE int sqlite3BtreeCommitPhaseOne(Btree *p, const char *zMaster){
|
|
int rc = SQLITE_OK;
|
|
if( p->inTrans==TRANS_WRITE ){
|
|
BtShared *pBt = p->pBt;
|
|
sqlite3BtreeEnter(p);
|
|
#ifndef SQLITE_OMIT_AUTOVACUUM
|
|
if( pBt->autoVacuum ){
|
|
rc = autoVacuumCommit(pBt);
|
|
if( rc!=SQLITE_OK ){
|
|
sqlite3BtreeLeave(p);
|
|
return rc;
|
|
}
|
|
}
|
|
#endif
|
|
rc = sqlite3PagerCommitPhaseOne(pBt->pPager, zMaster, 0);
|
|
sqlite3BtreeLeave(p);
|
|
}
|
|
return rc;
|
|
}
|
|
|
|
/*
|
|
** This function is called from both BtreeCommitPhaseTwo() and BtreeRollback()
|
|
** at the conclusion of a transaction.
|
|
*/
|
|
static void btreeEndTransaction(Btree *p){
|
|
BtShared *pBt = p->pBt;
|
|
assert( sqlite3BtreeHoldsMutex(p) );
|
|
|
|
btreeClearHasContent(pBt);
|
|
if( p->inTrans>TRANS_NONE && p->db->activeVdbeCnt>1 ){
|
|
/* If there are other active statements that belong to this database
|
|
** handle, downgrade to a read-only transaction. The other statements
|
|
** may still be reading from the database. */
|
|
downgradeAllSharedCacheTableLocks(p);
|
|
p->inTrans = TRANS_READ;
|
|
}else{
|
|
/* If the handle had any kind of transaction open, decrement the
|
|
** transaction count of the shared btree. If the transaction count
|
|
** reaches 0, set the shared state to TRANS_NONE. The unlockBtreeIfUnused()
|
|
** call below will unlock the pager. */
|
|
if( p->inTrans!=TRANS_NONE ){
|
|
clearAllSharedCacheTableLocks(p);
|
|
pBt->nTransaction--;
|
|
if( 0==pBt->nTransaction ){
|
|
pBt->inTransaction = TRANS_NONE;
|
|
}
|
|
}
|
|
|
|
/* Set the current transaction state to TRANS_NONE and unlock the
|
|
** pager if this call closed the only read or write transaction. */
|
|
p->inTrans = TRANS_NONE;
|
|
unlockBtreeIfUnused(pBt);
|
|
}
|
|
|
|
btreeIntegrity(p);
|
|
}
|
|
|
|
/*
|
|
** Commit the transaction currently in progress.
|
|
**
|
|
** This routine implements the second phase of a 2-phase commit. The
|
|
** sqlite3BtreeCommitPhaseOne() routine does the first phase and should
|
|
** be invoked prior to calling this routine. The sqlite3BtreeCommitPhaseOne()
|
|
** routine did all the work of writing information out to disk and flushing the
|
|
** contents so that they are written onto the disk platter. All this
|
|
** routine has to do is delete or truncate or zero the header in the
|
|
** the rollback journal (which causes the transaction to commit) and
|
|
** drop locks.
|
|
**
|
|
** This will release the write lock on the database file. If there
|
|
** are no active cursors, it also releases the read lock.
|
|
*/
|
|
SQLITE_PRIVATE int sqlite3BtreeCommitPhaseTwo(Btree *p){
|
|
|
|
if( p->inTrans==TRANS_NONE ) return SQLITE_OK;
|
|
sqlite3BtreeEnter(p);
|
|
btreeIntegrity(p);
|
|
|
|
/* If the handle has a write-transaction open, commit the shared-btrees
|
|
** transaction and set the shared state to TRANS_READ.
|
|
*/
|
|
if( p->inTrans==TRANS_WRITE ){
|
|
int rc;
|
|
BtShared *pBt = p->pBt;
|
|
assert( pBt->inTransaction==TRANS_WRITE );
|
|
assert( pBt->nTransaction>0 );
|
|
rc = sqlite3PagerCommitPhaseTwo(pBt->pPager);
|
|
if( rc!=SQLITE_OK ){
|
|
sqlite3BtreeLeave(p);
|
|
return rc;
|
|
}
|
|
pBt->inTransaction = TRANS_READ;
|
|
}
|
|
|
|
btreeEndTransaction(p);
|
|
sqlite3BtreeLeave(p);
|
|
return SQLITE_OK;
|
|
}
|
|
|
|
/*
|
|
** Do both phases of a commit.
|
|
*/
|
|
SQLITE_PRIVATE int sqlite3BtreeCommit(Btree *p){
|
|
int rc;
|
|
sqlite3BtreeEnter(p);
|
|
rc = sqlite3BtreeCommitPhaseOne(p, 0);
|
|
if( rc==SQLITE_OK ){
|
|
rc = sqlite3BtreeCommitPhaseTwo(p);
|
|
}
|
|
sqlite3BtreeLeave(p);
|
|
return rc;
|
|
}
|
|
|
|
#ifndef NDEBUG
|
|
/*
|
|
** Return the number of write-cursors open on this handle. This is for use
|
|
** in assert() expressions, so it is only compiled if NDEBUG is not
|
|
** defined.
|
|
**
|
|
** For the purposes of this routine, a write-cursor is any cursor that
|
|
** is capable of writing to the databse. That means the cursor was
|
|
** originally opened for writing and the cursor has not be disabled
|
|
** by having its state changed to CURSOR_FAULT.
|
|
*/
|
|
static int countWriteCursors(BtShared *pBt){
|
|
BtCursor *pCur;
|
|
int r = 0;
|
|
for(pCur=pBt->pCursor; pCur; pCur=pCur->pNext){
|
|
if( pCur->wrFlag && pCur->eState!=CURSOR_FAULT ) r++;
|
|
}
|
|
return r;
|
|
}
|
|
#endif
|
|
|
|
/*
|
|
** This routine sets the state to CURSOR_FAULT and the error
|
|
** code to errCode for every cursor on BtShared that pBtree
|
|
** references.
|
|
**
|
|
** Every cursor is tripped, including cursors that belong
|
|
** to other database connections that happen to be sharing
|
|
** the cache with pBtree.
|
|
**
|
|
** This routine gets called when a rollback occurs.
|
|
** All cursors using the same cache must be tripped
|
|
** to prevent them from trying to use the btree after
|
|
** the rollback. The rollback may have deleted tables
|
|
** or moved root pages, so it is not sufficient to
|
|
** save the state of the cursor. The cursor must be
|
|
** invalidated.
|
|
*/
|
|
SQLITE_PRIVATE void sqlite3BtreeTripAllCursors(Btree *pBtree, int errCode){
|
|
BtCursor *p;
|
|
sqlite3BtreeEnter(pBtree);
|
|
for(p=pBtree->pBt->pCursor; p; p=p->pNext){
|
|
int i;
|
|
sqlite3BtreeClearCursor(p);
|
|
p->eState = CURSOR_FAULT;
|
|
p->skipNext = errCode;
|
|
for(i=0; i<=p->iPage; i++){
|
|
releasePage(p->apPage[i]);
|
|
p->apPage[i] = 0;
|
|
}
|
|
}
|
|
sqlite3BtreeLeave(pBtree);
|
|
}
|
|
|
|
/*
|
|
** Rollback the transaction in progress. All cursors will be
|
|
** invalided by this operation. Any attempt to use a cursor
|
|
** that was open at the beginning of this operation will result
|
|
** in an error.
|
|
**
|
|
** This will release the write lock on the database file. If there
|
|
** are no active cursors, it also releases the read lock.
|
|
*/
|
|
SQLITE_PRIVATE int sqlite3BtreeRollback(Btree *p){
|
|
int rc;
|
|
BtShared *pBt = p->pBt;
|
|
MemPage *pPage1;
|
|
|
|
sqlite3BtreeEnter(p);
|
|
rc = saveAllCursors(pBt, 0, 0);
|
|
#ifndef SQLITE_OMIT_SHARED_CACHE
|
|
if( rc!=SQLITE_OK ){
|
|
/* This is a horrible situation. An IO or malloc() error occurred whilst
|
|
** trying to save cursor positions. If this is an automatic rollback (as
|
|
** the result of a constraint, malloc() failure or IO error) then
|
|
** the cache may be internally inconsistent (not contain valid trees) so
|
|
** we cannot simply return the error to the caller. Instead, abort
|
|
** all queries that may be using any of the cursors that failed to save.
|
|
*/
|
|
sqlite3BtreeTripAllCursors(p, rc);
|
|
}
|
|
#endif
|
|
btreeIntegrity(p);
|
|
|
|
if( p->inTrans==TRANS_WRITE ){
|
|
int rc2;
|
|
|
|
assert( TRANS_WRITE==pBt->inTransaction );
|
|
rc2 = sqlite3PagerRollback(pBt->pPager);
|
|
if( rc2!=SQLITE_OK ){
|
|
rc = rc2;
|
|
}
|
|
|
|
/* The rollback may have destroyed the pPage1->aData value. So
|
|
** call btreeGetPage() on page 1 again to make
|
|
** sure pPage1->aData is set correctly. */
|
|
if( btreeGetPage(pBt, 1, &pPage1, 0)==SQLITE_OK ){
|
|
int nPage = get4byte(28+(u8*)pPage1->aData);
|
|
testcase( nPage==0 );
|
|
if( nPage==0 ) sqlite3PagerPagecount(pBt->pPager, &nPage);
|
|
testcase( pBt->nPage!=nPage );
|
|
pBt->nPage = nPage;
|
|
releasePage(pPage1);
|
|
}
|
|
assert( countWriteCursors(pBt)==0 );
|
|
pBt->inTransaction = TRANS_READ;
|
|
}
|
|
|
|
btreeEndTransaction(p);
|
|
sqlite3BtreeLeave(p);
|
|
return rc;
|
|
}
|
|
|
|
/*
|
|
** Start a statement subtransaction. The subtransaction can can be rolled
|
|
** back independently of the main transaction. You must start a transaction
|
|
** before starting a subtransaction. The subtransaction is ended automatically
|
|
** if the main transaction commits or rolls back.
|
|
**
|
|
** Statement subtransactions are used around individual SQL statements
|
|
** that are contained within a BEGIN...COMMIT block. If a constraint
|
|
** error occurs within the statement, the effect of that one statement
|
|
** can be rolled back without having to rollback the entire transaction.
|
|
**
|
|
** A statement sub-transaction is implemented as an anonymous savepoint. The
|
|
** value passed as the second parameter is the total number of savepoints,
|
|
** including the new anonymous savepoint, open on the B-Tree. i.e. if there
|
|
** are no active savepoints and no other statement-transactions open,
|
|
** iStatement is 1. This anonymous savepoint can be released or rolled back
|
|
** using the sqlite3BtreeSavepoint() function.
|
|
*/
|
|
SQLITE_PRIVATE int sqlite3BtreeBeginStmt(Btree *p, int iStatement){
|
|
int rc;
|
|
BtShared *pBt = p->pBt;
|
|
sqlite3BtreeEnter(p);
|
|
assert( p->inTrans==TRANS_WRITE );
|
|
assert( pBt->readOnly==0 );
|
|
assert( iStatement>0 );
|
|
assert( iStatement>p->db->nSavepoint );
|
|
assert( pBt->inTransaction==TRANS_WRITE );
|
|
/* At the pager level, a statement transaction is a savepoint with
|
|
** an index greater than all savepoints created explicitly using
|
|
** SQL statements. It is illegal to open, release or rollback any
|
|
** such savepoints while the statement transaction savepoint is active.
|
|
*/
|
|
rc = sqlite3PagerOpenSavepoint(pBt->pPager, iStatement);
|
|
sqlite3BtreeLeave(p);
|
|
return rc;
|
|
}
|
|
|
|
/*
|
|
** The second argument to this function, op, is always SAVEPOINT_ROLLBACK
|
|
** or SAVEPOINT_RELEASE. This function either releases or rolls back the
|
|
** savepoint identified by parameter iSavepoint, depending on the value
|
|
** of op.
|
|
**
|
|
** Normally, iSavepoint is greater than or equal to zero. However, if op is
|
|
** SAVEPOINT_ROLLBACK, then iSavepoint may also be -1. In this case the
|
|
** contents of the entire transaction are rolled back. This is different
|
|
** from a normal transaction rollback, as no locks are released and the
|
|
** transaction remains open.
|
|
*/
|
|
SQLITE_PRIVATE int sqlite3BtreeSavepoint(Btree *p, int op, int iSavepoint){
|
|
int rc = SQLITE_OK;
|
|
if( p && p->inTrans==TRANS_WRITE ){
|
|
BtShared *pBt = p->pBt;
|
|
assert( op==SAVEPOINT_RELEASE || op==SAVEPOINT_ROLLBACK );
|
|
assert( iSavepoint>=0 || (iSavepoint==-1 && op==SAVEPOINT_ROLLBACK) );
|
|
sqlite3BtreeEnter(p);
|
|
rc = sqlite3PagerSavepoint(pBt->pPager, op, iSavepoint);
|
|
if( rc==SQLITE_OK ){
|
|
if( iSavepoint<0 && pBt->initiallyEmpty ) pBt->nPage = 0;
|
|
rc = newDatabase(pBt);
|
|
pBt->nPage = get4byte(28 + pBt->pPage1->aData);
|
|
|
|
/* The database size was written into the offset 28 of the header
|
|
** when the transaction started, so we know that the value at offset
|
|
** 28 is nonzero. */
|
|
assert( pBt->nPage>0 );
|
|
}
|
|
sqlite3BtreeLeave(p);
|
|
}
|
|
return rc;
|
|
}
|
|
|
|
/*
|
|
** Create a new cursor for the BTree whose root is on the page
|
|
** iTable. If a read-only cursor is requested, it is assumed that
|
|
** the caller already has at least a read-only transaction open
|
|
** on the database already. If a write-cursor is requested, then
|
|
** the caller is assumed to have an open write transaction.
|
|
**
|
|
** If wrFlag==0, then the cursor can only be used for reading.
|
|
** If wrFlag==1, then the cursor can be used for reading or for
|
|
** writing if other conditions for writing are also met. These
|
|
** are the conditions that must be met in order for writing to
|
|
** be allowed:
|
|
**
|
|
** 1: The cursor must have been opened with wrFlag==1
|
|
**
|
|
** 2: Other database connections that share the same pager cache
|
|
** but which are not in the READ_UNCOMMITTED state may not have
|
|
** cursors open with wrFlag==0 on the same table. Otherwise
|
|
** the changes made by this write cursor would be visible to
|
|
** the read cursors in the other database connection.
|
|
**
|
|
** 3: The database must be writable (not on read-only media)
|
|
**
|
|
** 4: There must be an active transaction.
|
|
**
|
|
** No checking is done to make sure that page iTable really is the
|
|
** root page of a b-tree. If it is not, then the cursor acquired
|
|
** will not work correctly.
|
|
**
|
|
** It is assumed that the sqlite3BtreeCursorZero() has been called
|
|
** on pCur to initialize the memory space prior to invoking this routine.
|
|
*/
|
|
static int btreeCursor(
|
|
Btree *p, /* The btree */
|
|
int iTable, /* Root page of table to open */
|
|
int wrFlag, /* 1 to write. 0 read-only */
|
|
struct KeyInfo *pKeyInfo, /* First arg to comparison function */
|
|
BtCursor *pCur /* Space for new cursor */
|
|
){
|
|
BtShared *pBt = p->pBt; /* Shared b-tree handle */
|
|
|
|
assert( sqlite3BtreeHoldsMutex(p) );
|
|
assert( wrFlag==0 || wrFlag==1 );
|
|
|
|
/* The following assert statements verify that if this is a sharable
|
|
** b-tree database, the connection is holding the required table locks,
|
|
** and that no other connection has any open cursor that conflicts with
|
|
** this lock. */
|
|
assert( hasSharedCacheTableLock(p, iTable, pKeyInfo!=0, wrFlag+1) );
|
|
assert( wrFlag==0 || !hasReadConflicts(p, iTable) );
|
|
|
|
/* Assert that the caller has opened the required transaction. */
|
|
assert( p->inTrans>TRANS_NONE );
|
|
assert( wrFlag==0 || p->inTrans==TRANS_WRITE );
|
|
assert( pBt->pPage1 && pBt->pPage1->aData );
|
|
|
|
if( NEVER(wrFlag && pBt->readOnly) ){
|
|
return SQLITE_READONLY;
|
|
}
|
|
if( iTable==1 && btreePagecount(pBt)==0 ){
|
|
return SQLITE_EMPTY;
|
|
}
|
|
|
|
/* Now that no other errors can occur, finish filling in the BtCursor
|
|
** variables and link the cursor into the BtShared list. */
|
|
pCur->pgnoRoot = (Pgno)iTable;
|
|
pCur->iPage = -1;
|
|
pCur->pKeyInfo = pKeyInfo;
|
|
pCur->pBtree = p;
|
|
pCur->pBt = pBt;
|
|
pCur->wrFlag = (u8)wrFlag;
|
|
pCur->pNext = pBt->pCursor;
|
|
if( pCur->pNext ){
|
|
pCur->pNext->pPrev = pCur;
|
|
}
|
|
pBt->pCursor = pCur;
|
|
pCur->eState = CURSOR_INVALID;
|
|
pCur->cachedRowid = 0;
|
|
return SQLITE_OK;
|
|
}
|
|
SQLITE_PRIVATE int sqlite3BtreeCursor(
|
|
Btree *p, /* The btree */
|
|
int iTable, /* Root page of table to open */
|
|
int wrFlag, /* 1 to write. 0 read-only */
|
|
struct KeyInfo *pKeyInfo, /* First arg to xCompare() */
|
|
BtCursor *pCur /* Write new cursor here */
|
|
){
|
|
int rc;
|
|
sqlite3BtreeEnter(p);
|
|
rc = btreeCursor(p, iTable, wrFlag, pKeyInfo, pCur);
|
|
sqlite3BtreeLeave(p);
|
|
return rc;
|
|
}
|
|
|
|
/*
|
|
** Return the size of a BtCursor object in bytes.
|
|
**
|
|
** This interfaces is needed so that users of cursors can preallocate
|
|
** sufficient storage to hold a cursor. The BtCursor object is opaque
|
|
** to users so they cannot do the sizeof() themselves - they must call
|
|
** this routine.
|
|
*/
|
|
SQLITE_PRIVATE int sqlite3BtreeCursorSize(void){
|
|
return ROUND8(sizeof(BtCursor));
|
|
}
|
|
|
|
/*
|
|
** Initialize memory that will be converted into a BtCursor object.
|
|
**
|
|
** The simple approach here would be to memset() the entire object
|
|
** to zero. But it turns out that the apPage[] and aiIdx[] arrays
|
|
** do not need to be zeroed and they are large, so we can save a lot
|
|
** of run-time by skipping the initialization of those elements.
|
|
*/
|
|
SQLITE_PRIVATE void sqlite3BtreeCursorZero(BtCursor *p){
|
|
memset(p, 0, offsetof(BtCursor, iPage));
|
|
}
|
|
|
|
/*
|
|
** Set the cached rowid value of every cursor in the same database file
|
|
** as pCur and having the same root page number as pCur. The value is
|
|
** set to iRowid.
|
|
**
|
|
** Only positive rowid values are considered valid for this cache.
|
|
** The cache is initialized to zero, indicating an invalid cache.
|
|
** A btree will work fine with zero or negative rowids. We just cannot
|
|
** cache zero or negative rowids, which means tables that use zero or
|
|
** negative rowids might run a little slower. But in practice, zero
|
|
** or negative rowids are very uncommon so this should not be a problem.
|
|
*/
|
|
SQLITE_PRIVATE void sqlite3BtreeSetCachedRowid(BtCursor *pCur, sqlite3_int64 iRowid){
|
|
BtCursor *p;
|
|
for(p=pCur->pBt->pCursor; p; p=p->pNext){
|
|
if( p->pgnoRoot==pCur->pgnoRoot ) p->cachedRowid = iRowid;
|
|
}
|
|
assert( pCur->cachedRowid==iRowid );
|
|
}
|
|
|
|
/*
|
|
** Return the cached rowid for the given cursor. A negative or zero
|
|
** return value indicates that the rowid cache is invalid and should be
|
|
** ignored. If the rowid cache has never before been set, then a
|
|
** zero is returned.
|
|
*/
|
|
SQLITE_PRIVATE sqlite3_int64 sqlite3BtreeGetCachedRowid(BtCursor *pCur){
|
|
return pCur->cachedRowid;
|
|
}
|
|
|
|
/*
|
|
** Close a cursor. The read lock on the database file is released
|
|
** when the last cursor is closed.
|
|
*/
|
|
SQLITE_PRIVATE int sqlite3BtreeCloseCursor(BtCursor *pCur){
|
|
Btree *pBtree = pCur->pBtree;
|
|
if( pBtree ){
|
|
int i;
|
|
BtShared *pBt = pCur->pBt;
|
|
sqlite3BtreeEnter(pBtree);
|
|
sqlite3BtreeClearCursor(pCur);
|
|
if( pCur->pPrev ){
|
|
pCur->pPrev->pNext = pCur->pNext;
|
|
}else{
|
|
pBt->pCursor = pCur->pNext;
|
|
}
|
|
if( pCur->pNext ){
|
|
pCur->pNext->pPrev = pCur->pPrev;
|
|
}
|
|
for(i=0; i<=pCur->iPage; i++){
|
|
releasePage(pCur->apPage[i]);
|
|
}
|
|
unlockBtreeIfUnused(pBt);
|
|
invalidateOverflowCache(pCur);
|
|
/* sqlite3_free(pCur); */
|
|
sqlite3BtreeLeave(pBtree);
|
|
}
|
|
return SQLITE_OK;
|
|
}
|
|
|
|
/*
|
|
** Make sure the BtCursor* given in the argument has a valid
|
|
** BtCursor.info structure. If it is not already valid, call
|
|
** btreeParseCell() to fill it in.
|
|
**
|
|
** BtCursor.info is a cache of the information in the current cell.
|
|
** Using this cache reduces the number of calls to btreeParseCell().
|
|
**
|
|
** 2007-06-25: There is a bug in some versions of MSVC that cause the
|
|
** compiler to crash when getCellInfo() is implemented as a macro.
|
|
** But there is a measureable speed advantage to using the macro on gcc
|
|
** (when less compiler optimizations like -Os or -O0 are used and the
|
|
** compiler is not doing agressive inlining.) So we use a real function
|
|
** for MSVC and a macro for everything else. Ticket #2457.
|
|
*/
|
|
#ifndef NDEBUG
|
|
static void assertCellInfo(BtCursor *pCur){
|
|
CellInfo info;
|
|
int iPage = pCur->iPage;
|
|
memset(&info, 0, sizeof(info));
|
|
btreeParseCell(pCur->apPage[iPage], pCur->aiIdx[iPage], &info);
|
|
assert( memcmp(&info, &pCur->info, sizeof(info))==0 );
|
|
}
|
|
#else
|
|
#define assertCellInfo(x)
|
|
#endif
|
|
#ifdef _MSC_VER
|
|
/* Use a real function in MSVC to work around bugs in that compiler. */
|
|
static void getCellInfo(BtCursor *pCur){
|
|
if( pCur->info.nSize==0 ){
|
|
int iPage = pCur->iPage;
|
|
btreeParseCell(pCur->apPage[iPage],pCur->aiIdx[iPage],&pCur->info);
|
|
pCur->validNKey = 1;
|
|
}else{
|
|
assertCellInfo(pCur);
|
|
}
|
|
}
|
|
#else /* if not _MSC_VER */
|
|
/* Use a macro in all other compilers so that the function is inlined */
|
|
#define getCellInfo(pCur) \
|
|
if( pCur->info.nSize==0 ){ \
|
|
int iPage = pCur->iPage; \
|
|
btreeParseCell(pCur->apPage[iPage],pCur->aiIdx[iPage],&pCur->info); \
|
|
pCur->validNKey = 1; \
|
|
}else{ \
|
|
assertCellInfo(pCur); \
|
|
}
|
|
#endif /* _MSC_VER */
|
|
|
|
#ifndef NDEBUG /* The next routine used only within assert() statements */
|
|
/*
|
|
** Return true if the given BtCursor is valid. A valid cursor is one
|
|
** that is currently pointing to a row in a (non-empty) table.
|
|
** This is a verification routine is used only within assert() statements.
|
|
*/
|
|
SQLITE_PRIVATE int sqlite3BtreeCursorIsValid(BtCursor *pCur){
|
|
return pCur && pCur->eState==CURSOR_VALID;
|
|
}
|
|
#endif /* NDEBUG */
|
|
|
|
/*
|
|
** Set *pSize to the size of the buffer needed to hold the value of
|
|
** the key for the current entry. If the cursor is not pointing
|
|
** to a valid entry, *pSize is set to 0.
|
|
**
|
|
** For a table with the INTKEY flag set, this routine returns the key
|
|
** itself, not the number of bytes in the key.
|
|
**
|
|
** The caller must position the cursor prior to invoking this routine.
|
|
**
|
|
** This routine cannot fail. It always returns SQLITE_OK.
|
|
*/
|
|
SQLITE_PRIVATE int sqlite3BtreeKeySize(BtCursor *pCur, i64 *pSize){
|
|
assert( cursorHoldsMutex(pCur) );
|
|
assert( pCur->eState==CURSOR_INVALID || pCur->eState==CURSOR_VALID );
|
|
if( pCur->eState!=CURSOR_VALID ){
|
|
*pSize = 0;
|
|
}else{
|
|
getCellInfo(pCur);
|
|
*pSize = pCur->info.nKey;
|
|
}
|
|
return SQLITE_OK;
|
|
}
|
|
|
|
/*
|
|
** Set *pSize to the number of bytes of data in the entry the
|
|
** cursor currently points to.
|
|
**
|
|
** The caller must guarantee that the cursor is pointing to a non-NULL
|
|
** valid entry. In other words, the calling procedure must guarantee
|
|
** that the cursor has Cursor.eState==CURSOR_VALID.
|
|
**
|
|
** Failure is not possible. This function always returns SQLITE_OK.
|
|
** It might just as well be a procedure (returning void) but we continue
|
|
** to return an integer result code for historical reasons.
|
|
*/
|
|
SQLITE_PRIVATE int sqlite3BtreeDataSize(BtCursor *pCur, u32 *pSize){
|
|
assert( cursorHoldsMutex(pCur) );
|
|
assert( pCur->eState==CURSOR_VALID );
|
|
getCellInfo(pCur);
|
|
*pSize = pCur->info.nData;
|
|
return SQLITE_OK;
|
|
}
|
|
|
|
/*
|
|
** Given the page number of an overflow page in the database (parameter
|
|
** ovfl), this function finds the page number of the next page in the
|
|
** linked list of overflow pages. If possible, it uses the auto-vacuum
|
|
** pointer-map data instead of reading the content of page ovfl to do so.
|
|
**
|
|
** If an error occurs an SQLite error code is returned. Otherwise:
|
|
**
|
|
** The page number of the next overflow page in the linked list is
|
|
** written to *pPgnoNext. If page ovfl is the last page in its linked
|
|
** list, *pPgnoNext is set to zero.
|
|
**
|
|
** If ppPage is not NULL, and a reference to the MemPage object corresponding
|
|
** to page number pOvfl was obtained, then *ppPage is set to point to that
|
|
** reference. It is the responsibility of the caller to call releasePage()
|
|
** on *ppPage to free the reference. In no reference was obtained (because
|
|
** the pointer-map was used to obtain the value for *pPgnoNext), then
|
|
** *ppPage is set to zero.
|
|
*/
|
|
static int getOverflowPage(
|
|
BtShared *pBt, /* The database file */
|
|
Pgno ovfl, /* Current overflow page number */
|
|
MemPage **ppPage, /* OUT: MemPage handle (may be NULL) */
|
|
Pgno *pPgnoNext /* OUT: Next overflow page number */
|
|
){
|
|
Pgno next = 0;
|
|
MemPage *pPage = 0;
|
|
int rc = SQLITE_OK;
|
|
|
|
assert( sqlite3_mutex_held(pBt->mutex) );
|
|
assert(pPgnoNext);
|
|
|
|
#if 0 // This shortcut is not allowed since we want to validate child->parent links when traversing
|
|
//#ifndef SQLITE_OMIT_AUTOVACUUM
|
|
/* Try to find the next page in the overflow list using the
|
|
** autovacuum pointer-map pages. Guess that the next page in
|
|
** the overflow list is page number (ovfl+1). If that guess turns
|
|
** out to be wrong, fall back to loading the data of page
|
|
** number ovfl to determine the next page number.
|
|
*/
|
|
if( pBt->autoVacuum ){
|
|
Pgno pgno;
|
|
Pgno iGuess = ovfl+1;
|
|
u8 eType;
|
|
|
|
while( PTRMAP_ISPAGE(pBt, iGuess) || iGuess==PENDING_BYTE_PAGE(pBt) ){
|
|
iGuess++;
|
|
}
|
|
|
|
if( iGuess<=btreePagecount(pBt) ){
|
|
rc = ptrmapGet(pBt, iGuess, &eType, &pgno);
|
|
if( rc==SQLITE_OK && eType==PTRMAP_OVERFLOW2 && pgno==ovfl ){
|
|
next = iGuess;
|
|
rc = SQLITE_DONE;
|
|
}
|
|
}
|
|
}
|
|
#endif
|
|
|
|
assert( next==0 || rc==SQLITE_DONE );
|
|
if( rc==SQLITE_OK ){
|
|
rc = btreeGetPage(pBt, ovfl, &pPage, 0);
|
|
assert( rc==SQLITE_OK || pPage==0 );
|
|
if( rc==SQLITE_OK ){
|
|
next = get4byte(pPage->aData);
|
|
}
|
|
}
|
|
|
|
*pPgnoNext = next;
|
|
if( ppPage ){
|
|
*ppPage = pPage;
|
|
}else{
|
|
releasePage(pPage);
|
|
}
|
|
return (rc==SQLITE_DONE ? SQLITE_OK : rc);
|
|
}
|
|
|
|
/*
|
|
** Copy data from a buffer to a page, or from a page to a buffer.
|
|
**
|
|
** pPayload is a pointer to data stored on database page pDbPage.
|
|
** If argument eOp is false, then nByte bytes of data are copied
|
|
** from pPayload to the buffer pointed at by pBuf. If eOp is true,
|
|
** then sqlite3PagerWrite() is called on pDbPage and nByte bytes
|
|
** of data are copied from the buffer pBuf to pPayload.
|
|
**
|
|
** SQLITE_OK is returned on success, otherwise an error code.
|
|
*/
|
|
static int copyPayload(
|
|
void *pPayload, /* Pointer to page data */
|
|
void *pBuf, /* Pointer to buffer */
|
|
int nByte, /* Number of bytes to copy */
|
|
int eOp, /* 0 -> copy from page, 1 -> copy to page */
|
|
DbPage *pDbPage /* Page containing pPayload */
|
|
){
|
|
if( eOp ){
|
|
/* Copy data from buffer to page (a write operation) */
|
|
int rc = sqlite3PagerWrite(pDbPage);
|
|
if( rc!=SQLITE_OK ){
|
|
return rc;
|
|
}
|
|
memcpy(pPayload, pBuf, nByte);
|
|
}else{
|
|
/* Copy data from page to buffer (a read operation) */
|
|
memcpy(pBuf, pPayload, nByte);
|
|
}
|
|
return SQLITE_OK;
|
|
}
|
|
|
|
/*
|
|
** This function is used to read or overwrite payload information
|
|
** for the entry that the pCur cursor is pointing to. If the eOp
|
|
** parameter is 0, this is a read operation (data copied into
|
|
** buffer pBuf). If it is non-zero, a write (data copied from
|
|
** buffer pBuf).
|
|
**
|
|
** A total of "amt" bytes are read or written beginning at "offset".
|
|
** Data is read to or from the buffer pBuf.
|
|
**
|
|
** The content being read or written might appear on the main page
|
|
** or be scattered out on multiple overflow pages.
|
|
**
|
|
** If the BtCursor.isIncrblobHandle flag is set, and the current
|
|
** cursor entry uses one or more overflow pages, this function
|
|
** allocates space for and lazily popluates the overflow page-list
|
|
** cache array (BtCursor.aOverflow). Subsequent calls use this
|
|
** cache to make seeking to the supplied offset more efficient.
|
|
**
|
|
** Once an overflow page-list cache has been allocated, it may be
|
|
** invalidated if some other cursor writes to the same table, or if
|
|
** the cursor is moved to a different row. Additionally, in auto-vacuum
|
|
** mode, the following events may invalidate an overflow page-list cache.
|
|
**
|
|
** * An incremental vacuum,
|
|
** * A commit in auto_vacuum="full" mode,
|
|
** * Creating a table (may require moving an overflow page).
|
|
*/
|
|
static int accessPayload(
|
|
BtCursor *pCur, /* Cursor pointing to entry to read from */
|
|
u32 offset, /* Begin reading this far into payload */
|
|
u32 amt, /* Read this many bytes */
|
|
unsigned char *pBuf, /* Write the bytes into this buffer */
|
|
int eOp /* zero to read. non-zero to write. */
|
|
){
|
|
unsigned char *aPayload;
|
|
int rc = SQLITE_OK;
|
|
u32 nKey;
|
|
int iIdx = 0;
|
|
MemPage *pPage = pCur->apPage[pCur->iPage]; /* Btree page of current entry */
|
|
BtShared *pBt = pCur->pBt; /* Btree this cursor belongs to */
|
|
|
|
assert( pPage );
|
|
assert( pCur->eState==CURSOR_VALID );
|
|
assert( pCur->aiIdx[pCur->iPage]<pPage->nCell );
|
|
assert( cursorHoldsMutex(pCur) );
|
|
|
|
getCellInfo(pCur);
|
|
aPayload = pCur->info.pCell + pCur->info.nHeader;
|
|
nKey = (pPage->intKey ? 0 : (int)pCur->info.nKey);
|
|
|
|
if( NEVER(offset+amt > nKey+pCur->info.nData)
|
|
|| &aPayload[pCur->info.nLocal] > &pPage->aData[pBt->usableSize]
|
|
){
|
|
/* Trying to read or write past the end of the data is an error */
|
|
return SQLITE_CORRUPT_BKPT;
|
|
}
|
|
|
|
/* Check if data must be read/written to/from the btree page itself. */
|
|
if( offset<pCur->info.nLocal ){
|
|
int a = amt;
|
|
if( a+offset>pCur->info.nLocal ){
|
|
a = pCur->info.nLocal - offset;
|
|
}
|
|
rc = copyPayload(&aPayload[offset], pBuf, a, eOp, pPage->pDbPage);
|
|
offset = 0;
|
|
pBuf += a;
|
|
amt -= a;
|
|
}else{
|
|
offset -= pCur->info.nLocal;
|
|
}
|
|
|
|
if( rc==SQLITE_OK && amt>0 ){
|
|
const u32 ovflSize = pBt->usableSize - 4; /* Bytes content per ovfl page */
|
|
Pgno nextPage;
|
|
|
|
nextPage = get4byte(&aPayload[pCur->info.nLocal]);
|
|
Pgno nextPageParent = pPage->pgno; // Expected parent of nextPage, to be verified before using the page
|
|
|
|
#ifndef SQLITE_OMIT_INCRBLOB
|
|
/* If the isIncrblobHandle flag is set and the BtCursor.aOverflow[]
|
|
** has not been allocated, allocate it now. The array is sized at
|
|
** one entry for each overflow page in the overflow chain. The
|
|
** page number of the first overflow page is stored in aOverflow[0],
|
|
** etc. A value of 0 in the aOverflow[] array means "not yet known"
|
|
** (the cache is lazily populated).
|
|
*/
|
|
if( pCur->isIncrblobHandle && !pCur->aOverflow ){
|
|
int nOvfl = (pCur->info.nPayload-pCur->info.nLocal+ovflSize-1)/ovflSize;
|
|
pCur->aOverflow = (Pgno *)sqlite3MallocZero(sizeof(Pgno)*nOvfl);
|
|
/* nOvfl is always positive. If it were zero, fetchPayload would have
|
|
** been used instead of this routine. */
|
|
if( ALWAYS(nOvfl) && !pCur->aOverflow ){
|
|
rc = SQLITE_NOMEM;
|
|
}
|
|
}
|
|
|
|
/* If the overflow page-list cache has been allocated and the
|
|
** entry for the first required overflow page is valid, skip
|
|
** directly to it.
|
|
*/
|
|
if( pCur->aOverflow && pCur->aOverflow[offset/ovflSize] ){
|
|
iIdx = (offset/ovflSize);
|
|
nextPage = pCur->aOverflow[iIdx];
|
|
nextPageParent = 0; // No need to verify link since page was from cache was from cache
|
|
offset = (offset%ovflSize);
|
|
}
|
|
#endif
|
|
|
|
for( ; rc==SQLITE_OK && amt>0 && nextPage; iIdx++){
|
|
|
|
// Verify the child to parent link of the next page to read, if necessary
|
|
if(nextPageParent != 0) {
|
|
rc = verifyParentChildLink(pBt, nextPageParent, nextPage);
|
|
if(rc != SQLITE_OK)
|
|
return rc;
|
|
}
|
|
|
|
#ifndef SQLITE_OMIT_INCRBLOB
|
|
/* If required, populate the overflow page-list cache. */
|
|
if( pCur->aOverflow ){
|
|
assert(!pCur->aOverflow[iIdx] || pCur->aOverflow[iIdx]==nextPage);
|
|
pCur->aOverflow[iIdx] = nextPage;
|
|
}
|
|
#endif
|
|
|
|
if( offset>=ovflSize ){
|
|
/* The only reason to read this page is to obtain the page
|
|
** number for the next page in the overflow chain. The page
|
|
** data is not required. So first try to lookup the overflow
|
|
** page-list cache, if any, then fall back to the getOverflowPage()
|
|
** function.
|
|
*/
|
|
#ifndef SQLITE_OMIT_INCRBLOB
|
|
if( pCur->aOverflow && pCur->aOverflow[iIdx+1] ){
|
|
nextPage = pCur->aOverflow[iIdx+1];
|
|
nextPageParent = 0; // No need to verify link since page was from cache
|
|
} else
|
|
#endif
|
|
{
|
|
nextPageParent = nextPage;
|
|
rc = getOverflowPage(pBt, nextPage, 0, &nextPage);
|
|
}
|
|
offset -= ovflSize;
|
|
}else{
|
|
/* Need to read this page properly. It contains some of the
|
|
** range of data that is being read (eOp==0) or written (eOp!=0).
|
|
*/
|
|
DbPage *pDbPage;
|
|
int a = amt;
|
|
rc = sqlite3PagerGet(pBt->pPager, nextPage, &pDbPage);
|
|
if( rc==SQLITE_OK ){
|
|
aPayload = sqlite3PagerGetData(pDbPage);
|
|
nextPageParent = nextPage;
|
|
nextPage = get4byte(aPayload);
|
|
if( a + offset > ovflSize ){
|
|
a = ovflSize - offset;
|
|
}
|
|
rc = copyPayload(&aPayload[offset+4], pBuf, a, eOp, pDbPage);
|
|
sqlite3PagerUnref(pDbPage);
|
|
offset = 0;
|
|
amt -= a;
|
|
pBuf += a;
|
|
}
|
|
}
|
|
}
|
|
}
|
|
|
|
if( rc==SQLITE_OK && amt>0 ){
|
|
return SQLITE_CORRUPT_BKPT;
|
|
}
|
|
return rc;
|
|
}
|
|
|
|
/*
|
|
** Read part of the key associated with cursor pCur. Exactly
|
|
** "amt" bytes will be transfered into pBuf[]. The transfer
|
|
** begins at "offset".
|
|
**
|
|
** The caller must ensure that pCur is pointing to a valid row
|
|
** in the table.
|
|
**
|
|
** Return SQLITE_OK on success or an error code if anything goes
|
|
** wrong. An error is returned if "offset+amt" is larger than
|
|
** the available payload.
|
|
*/
|
|
SQLITE_PRIVATE int sqlite3BtreeKey(BtCursor *pCur, u32 offset, u32 amt, void *pBuf){
|
|
assert( cursorHoldsMutex(pCur) );
|
|
assert( pCur->eState==CURSOR_VALID );
|
|
assert( pCur->iPage>=0 && pCur->apPage[pCur->iPage] );
|
|
assert( pCur->aiIdx[pCur->iPage]<pCur->apPage[pCur->iPage]->nCell );
|
|
return accessPayload(pCur, offset, amt, (unsigned char*)pBuf, 0);
|
|
}
|
|
|
|
/*
|
|
** Read part of the data associated with cursor pCur. Exactly
|
|
** "amt" bytes will be transfered into pBuf[]. The transfer
|
|
** begins at "offset".
|
|
**
|
|
** Return SQLITE_OK on success or an error code if anything goes
|
|
** wrong. An error is returned if "offset+amt" is larger than
|
|
** the available payload.
|
|
*/
|
|
SQLITE_PRIVATE int sqlite3BtreeData(BtCursor *pCur, u32 offset, u32 amt, void *pBuf){
|
|
int rc;
|
|
|
|
#ifndef SQLITE_OMIT_INCRBLOB
|
|
if ( pCur->eState==CURSOR_INVALID ){
|
|
return SQLITE_ABORT;
|
|
}
|
|
#endif
|
|
|
|
assert( cursorHoldsMutex(pCur) );
|
|
rc = restoreCursorPosition(pCur);
|
|
if( rc==SQLITE_OK ){
|
|
assert( pCur->eState==CURSOR_VALID );
|
|
assert( pCur->iPage>=0 && pCur->apPage[pCur->iPage] );
|
|
assert( pCur->aiIdx[pCur->iPage]<pCur->apPage[pCur->iPage]->nCell );
|
|
rc = accessPayload(pCur, offset, amt, pBuf, 0);
|
|
}
|
|
return rc;
|
|
}
|
|
|
|
/*
|
|
** Return a pointer to payload information from the entry that the
|
|
** pCur cursor is pointing to. The pointer is to the beginning of
|
|
** the key if skipKey==0 and it points to the beginning of data if
|
|
** skipKey==1. The number of bytes of available key/data is written
|
|
** into *pAmt. If *pAmt==0, then the value returned will not be
|
|
** a valid pointer.
|
|
**
|
|
** This routine is an optimization. It is common for the entire key
|
|
** and data to fit on the local page and for there to be no overflow
|
|
** pages. When that is so, this routine can be used to access the
|
|
** key and data without making a copy. If the key and/or data spills
|
|
** onto overflow pages, then accessPayload() must be used to reassemble
|
|
** the key/data and copy it into a preallocated buffer.
|
|
**
|
|
** The pointer returned by this routine looks directly into the cached
|
|
** page of the database. The data might change or move the next time
|
|
** any btree routine is called.
|
|
*/
|
|
static const unsigned char *fetchPayload(
|
|
BtCursor *pCur, /* Cursor pointing to entry to read from */
|
|
int *pAmt, /* Write the number of available bytes here */
|
|
int skipKey /* read beginning at data if this is true */
|
|
){
|
|
unsigned char *aPayload;
|
|
MemPage *pPage;
|
|
u32 nKey;
|
|
u32 nLocal;
|
|
|
|
assert( pCur!=0 && pCur->iPage>=0 && pCur->apPage[pCur->iPage]);
|
|
assert( pCur->eState==CURSOR_VALID );
|
|
assert( cursorHoldsMutex(pCur) );
|
|
pPage = pCur->apPage[pCur->iPage];
|
|
assert( pCur->aiIdx[pCur->iPage]<pPage->nCell );
|
|
if( NEVER(pCur->info.nSize==0) ){
|
|
btreeParseCell(pCur->apPage[pCur->iPage], pCur->aiIdx[pCur->iPage],
|
|
&pCur->info);
|
|
}
|
|
aPayload = pCur->info.pCell;
|
|
aPayload += pCur->info.nHeader;
|
|
if( pPage->intKey ){
|
|
nKey = 0;
|
|
}else{
|
|
nKey = (int)pCur->info.nKey;
|
|
}
|
|
if( skipKey ){
|
|
aPayload += nKey;
|
|
nLocal = pCur->info.nLocal - nKey;
|
|
}else{
|
|
nLocal = pCur->info.nLocal;
|
|
assert( nLocal<=nKey );
|
|
}
|
|
*pAmt = nLocal;
|
|
return aPayload;
|
|
}
|
|
|
|
|
|
/*
|
|
** For the entry that cursor pCur is point to, return as
|
|
** many bytes of the key or data as are available on the local
|
|
** b-tree page. Write the number of available bytes into *pAmt.
|
|
**
|
|
** The pointer returned is ephemeral. The key/data may move
|
|
** or be destroyed on the next call to any Btree routine,
|
|
** including calls from other threads against the same cache.
|
|
** Hence, a mutex on the BtShared should be held prior to calling
|
|
** this routine.
|
|
**
|
|
** These routines is used to get quick access to key and data
|
|
** in the common case where no overflow pages are used.
|
|
*/
|
|
SQLITE_PRIVATE const void *sqlite3BtreeKeyFetch(BtCursor *pCur, int *pAmt){
|
|
const void *p = 0;
|
|
assert( sqlite3_mutex_held(pCur->pBtree->db->mutex) );
|
|
assert( cursorHoldsMutex(pCur) );
|
|
if( ALWAYS(pCur->eState==CURSOR_VALID) ){
|
|
p = (const void*)fetchPayload(pCur, pAmt, 0);
|
|
}
|
|
return p;
|
|
}
|
|
SQLITE_PRIVATE const void *sqlite3BtreeDataFetch(BtCursor *pCur, int *pAmt){
|
|
const void *p = 0;
|
|
assert( sqlite3_mutex_held(pCur->pBtree->db->mutex) );
|
|
assert( cursorHoldsMutex(pCur) );
|
|
if( ALWAYS(pCur->eState==CURSOR_VALID) ){
|
|
p = (const void*)fetchPayload(pCur, pAmt, 1);
|
|
}
|
|
return p;
|
|
}
|
|
|
|
|
|
/*
|
|
** Move the cursor down to a new child page. The newPgno argument is the
|
|
** page number of the child page to move to.
|
|
**
|
|
** This function returns SQLITE_CORRUPT if the page-header flags field of
|
|
** the new child page does not match the flags field of the parent (i.e.
|
|
** if an intkey page appears to be the parent of a non-intkey page, or
|
|
** vice-versa).
|
|
*/
|
|
static int moveToChild(BtCursor *pCur, u32 newPgno){
|
|
int rc;
|
|
int i = pCur->iPage;
|
|
MemPage *pNewPage;
|
|
BtShared *pBt = pCur->pBt;
|
|
|
|
assert( cursorHoldsMutex(pCur) );
|
|
assert( pCur->eState==CURSOR_VALID );
|
|
assert( pCur->iPage<BTCURSOR_MAX_DEPTH );
|
|
if( pCur->iPage>=(BTCURSOR_MAX_DEPTH-1) ){
|
|
return SQLITE_CORRUPT_BKPT;
|
|
}
|
|
|
|
rc = verifyParentChildLink(pBt, pCur->apPage[i]->pgno, newPgno);
|
|
if(rc != SQLITE_OK)
|
|
return rc;
|
|
|
|
rc = getAndInitPage(pBt, newPgno, &pNewPage);
|
|
if( rc ) return rc;
|
|
pCur->apPage[i+1] = pNewPage;
|
|
pCur->aiIdx[i+1] = 0;
|
|
pCur->iPage++;
|
|
|
|
pCur->info.nSize = 0;
|
|
pCur->validNKey = 0;
|
|
if( pNewPage->nCell<1 || pNewPage->intKey!=pCur->apPage[i]->intKey ){
|
|
return SQLITE_CORRUPT_BKPT;
|
|
}
|
|
return SQLITE_OK;
|
|
}
|
|
|
|
#ifndef NDEBUG
|
|
/*
|
|
** Page pParent is an internal (non-leaf) tree page. This function
|
|
** asserts that page number iChild is the left-child if the iIdx'th
|
|
** cell in page pParent. Or, if iIdx is equal to the total number of
|
|
** cells in pParent, that page number iChild is the right-child of
|
|
** the page.
|
|
*/
|
|
static void assertParentIndex(MemPage *pParent, int iIdx, Pgno iChild){
|
|
assert( iIdx<=pParent->nCell );
|
|
if( iIdx==pParent->nCell ){
|
|
assert( get4byte(&pParent->aData[pParent->hdrOffset+8])==iChild );
|
|
}else{
|
|
assert( get4byte(findCell(pParent, iIdx))==iChild );
|
|
}
|
|
}
|
|
#else
|
|
# define assertParentIndex(x,y,z)
|
|
#endif
|
|
|
|
/*
|
|
** Move the cursor up to the parent page.
|
|
**
|
|
** pCur->idx is set to the cell index that contains the pointer
|
|
** to the page we are coming from. If we are coming from the
|
|
** right-most child page then pCur->idx is set to one more than
|
|
** the largest cell index.
|
|
*/
|
|
static void moveToParent(BtCursor *pCur){
|
|
assert( cursorHoldsMutex(pCur) );
|
|
assert( pCur->eState==CURSOR_VALID );
|
|
assert( pCur->iPage>0 );
|
|
assert( pCur->apPage[pCur->iPage] );
|
|
assertParentIndex(
|
|
pCur->apPage[pCur->iPage-1],
|
|
pCur->aiIdx[pCur->iPage-1],
|
|
pCur->apPage[pCur->iPage]->pgno
|
|
);
|
|
releasePage(pCur->apPage[pCur->iPage]);
|
|
pCur->iPage--;
|
|
pCur->info.nSize = 0;
|
|
pCur->validNKey = 0;
|
|
}
|
|
|
|
/*
|
|
** Move the cursor to point to the root page of its b-tree structure.
|
|
**
|
|
** If the table has a virtual root page, then the cursor is moved to point
|
|
** to the virtual root page instead of the actual root page. A table has a
|
|
** virtual root page when the actual root page contains no cells and a
|
|
** single child page. This can only happen with the table rooted at page 1.
|
|
**
|
|
** If the b-tree structure is empty, the cursor state is set to
|
|
** CURSOR_INVALID. Otherwise, the cursor is set to point to the first
|
|
** cell located on the root (or virtual root) page and the cursor state
|
|
** is set to CURSOR_VALID.
|
|
**
|
|
** If this function returns successfully, it may be assumed that the
|
|
** page-header flags indicate that the [virtual] root-page is the expected
|
|
** kind of b-tree page (i.e. if when opening the cursor the caller did not
|
|
** specify a KeyInfo structure the flags byte is set to 0x05 or 0x0D,
|
|
** indicating a table b-tree, or if the caller did specify a KeyInfo
|
|
** structure the flags byte is set to 0x02 or 0x0A, indicating an index
|
|
** b-tree).
|
|
*/
|
|
static int moveToRoot(BtCursor *pCur){
|
|
MemPage *pRoot;
|
|
int rc = SQLITE_OK;
|
|
Btree *p = pCur->pBtree;
|
|
BtShared *pBt = p->pBt;
|
|
|
|
assert( cursorHoldsMutex(pCur) );
|
|
assert( CURSOR_INVALID < CURSOR_REQUIRESEEK );
|
|
assert( CURSOR_VALID < CURSOR_REQUIRESEEK );
|
|
assert( CURSOR_FAULT > CURSOR_REQUIRESEEK );
|
|
if( pCur->eState>=CURSOR_REQUIRESEEK ){
|
|
if( pCur->eState==CURSOR_FAULT ){
|
|
assert( pCur->skipNext!=SQLITE_OK );
|
|
return pCur->skipNext;
|
|
}
|
|
sqlite3BtreeClearCursor(pCur);
|
|
}
|
|
|
|
if( pCur->iPage>=0 ){
|
|
int i;
|
|
for(i=1; i<=pCur->iPage; i++){
|
|
releasePage(pCur->apPage[i]);
|
|
}
|
|
pCur->iPage = 0;
|
|
}else{
|
|
rc = getAndInitPage(pBt, pCur->pgnoRoot, &pCur->apPage[0]);
|
|
if( rc!=SQLITE_OK ){
|
|
pCur->eState = CURSOR_INVALID;
|
|
return rc;
|
|
}
|
|
pCur->iPage = 0;
|
|
|
|
/* If pCur->pKeyInfo is not NULL, then the caller that opened this cursor
|
|
** expected to open it on an index b-tree. Otherwise, if pKeyInfo is
|
|
** NULL, the caller expects a table b-tree. If this is not the case,
|
|
** return an SQLITE_CORRUPT error. */
|
|
assert( pCur->apPage[0]->intKey==1 || pCur->apPage[0]->intKey==0 );
|
|
if( (pCur->pKeyInfo==0)!=pCur->apPage[0]->intKey ){
|
|
return SQLITE_CORRUPT_BKPT;
|
|
}
|
|
}
|
|
|
|
/* Assert that the root page is of the correct type. This must be the
|
|
** case as the call to this function that loaded the root-page (either
|
|
** this call or a previous invocation) would have detected corruption
|
|
** if the assumption were not true, and it is not possible for the flags
|
|
** byte to have been modified while this cursor is holding a reference
|
|
** to the page. */
|
|
pRoot = pCur->apPage[0];
|
|
assert( pRoot->pgno==pCur->pgnoRoot );
|
|
assert( pRoot->isInit && (pCur->pKeyInfo==0)==pRoot->intKey );
|
|
|
|
pCur->aiIdx[0] = 0;
|
|
pCur->info.nSize = 0;
|
|
pCur->atLast = 0;
|
|
pCur->validNKey = 0;
|
|
|
|
if( pRoot->nCell==0 && !pRoot->leaf ){
|
|
Pgno subpage;
|
|
if( pRoot->pgno!=1 ) return SQLITE_CORRUPT_BKPT;
|
|
subpage = get4byte(&pRoot->aData[pRoot->hdrOffset+8]);
|
|
pCur->eState = CURSOR_VALID;
|
|
rc = moveToChild(pCur, subpage);
|
|
}else{
|
|
pCur->eState = ((pRoot->nCell>0)?CURSOR_VALID:CURSOR_INVALID);
|
|
}
|
|
return rc;
|
|
}
|
|
|
|
/*
|
|
** Move the cursor down to the left-most leaf entry beneath the
|
|
** entry to which it is currently pointing.
|
|
**
|
|
** The left-most leaf is the one with the smallest key - the first
|
|
** in ascending order.
|
|
*/
|
|
static int moveToLeftmost(BtCursor *pCur){
|
|
Pgno pgno;
|
|
int rc = SQLITE_OK;
|
|
MemPage *pPage;
|
|
|
|
assert( cursorHoldsMutex(pCur) );
|
|
assert( pCur->eState==CURSOR_VALID );
|
|
while( rc==SQLITE_OK && !(pPage = pCur->apPage[pCur->iPage])->leaf ){
|
|
assert( pCur->aiIdx[pCur->iPage]<pPage->nCell );
|
|
pgno = get4byte(findCell(pPage, pCur->aiIdx[pCur->iPage]));
|
|
rc = moveToChild(pCur, pgno);
|
|
}
|
|
return rc;
|
|
}
|
|
|
|
/*
|
|
** Move the cursor down to the right-most leaf entry beneath the
|
|
** page to which it is currently pointing. Notice the difference
|
|
** between moveToLeftmost() and moveToRightmost(). moveToLeftmost()
|
|
** finds the left-most entry beneath the *entry* whereas moveToRightmost()
|
|
** finds the right-most entry beneath the *page*.
|
|
**
|
|
** The right-most entry is the one with the largest key - the last
|
|
** key in ascending order.
|
|
*/
|
|
static int moveToRightmost(BtCursor *pCur){
|
|
Pgno pgno;
|
|
int rc = SQLITE_OK;
|
|
MemPage *pPage = 0;
|
|
|
|
assert( cursorHoldsMutex(pCur) );
|
|
assert( pCur->eState==CURSOR_VALID );
|
|
while( rc==SQLITE_OK && !(pPage = pCur->apPage[pCur->iPage])->leaf ){
|
|
pgno = get4byte(&pPage->aData[pPage->hdrOffset+8]);
|
|
pCur->aiIdx[pCur->iPage] = pPage->nCell;
|
|
rc = moveToChild(pCur, pgno);
|
|
}
|
|
if( rc==SQLITE_OK ){
|
|
pCur->aiIdx[pCur->iPage] = pPage->nCell-1;
|
|
pCur->info.nSize = 0;
|
|
pCur->validNKey = 0;
|
|
}
|
|
return rc;
|
|
}
|
|
|
|
/* Move the cursor to the first entry in the table. Return SQLITE_OK
|
|
** on success. Set *pRes to 0 if the cursor actually points to something
|
|
** or set *pRes to 1 if the table is empty.
|
|
*/
|
|
SQLITE_PRIVATE int sqlite3BtreeFirst(BtCursor *pCur, int *pRes){
|
|
int rc;
|
|
|
|
assert( cursorHoldsMutex(pCur) );
|
|
assert( sqlite3_mutex_held(pCur->pBtree->db->mutex) );
|
|
rc = moveToRoot(pCur);
|
|
if( rc==SQLITE_OK ){
|
|
if( pCur->eState==CURSOR_INVALID ){
|
|
assert( pCur->apPage[pCur->iPage]->nCell==0 );
|
|
*pRes = 1;
|
|
}else{
|
|
assert( pCur->apPage[pCur->iPage]->nCell>0 );
|
|
*pRes = 0;
|
|
rc = moveToLeftmost(pCur);
|
|
}
|
|
}
|
|
return rc;
|
|
}
|
|
|
|
/* Move the cursor to the last entry in the table. Return SQLITE_OK
|
|
** on success. Set *pRes to 0 if the cursor actually points to something
|
|
** or set *pRes to 1 if the table is empty.
|
|
*/
|
|
SQLITE_PRIVATE int sqlite3BtreeLast(BtCursor *pCur, int *pRes){
|
|
int rc;
|
|
|
|
assert( cursorHoldsMutex(pCur) );
|
|
assert( sqlite3_mutex_held(pCur->pBtree->db->mutex) );
|
|
|
|
/* If the cursor already points to the last entry, this is a no-op. */
|
|
if( CURSOR_VALID==pCur->eState && pCur->atLast ){
|
|
#ifdef SQLITE_DEBUG
|
|
/* This block serves to assert() that the cursor really does point
|
|
** to the last entry in the b-tree. */
|
|
int ii;
|
|
for(ii=0; ii<pCur->iPage; ii++){
|
|
assert( pCur->aiIdx[ii]==pCur->apPage[ii]->nCell );
|
|
}
|
|
assert( pCur->aiIdx[pCur->iPage]==pCur->apPage[pCur->iPage]->nCell-1 );
|
|
assert( pCur->apPage[pCur->iPage]->leaf );
|
|
#endif
|
|
return SQLITE_OK;
|
|
}
|
|
|
|
rc = moveToRoot(pCur);
|
|
if( rc==SQLITE_OK ){
|
|
if( CURSOR_INVALID==pCur->eState ){
|
|
assert( pCur->apPage[pCur->iPage]->nCell==0 );
|
|
*pRes = 1;
|
|
}else{
|
|
assert( pCur->eState==CURSOR_VALID );
|
|
*pRes = 0;
|
|
rc = moveToRightmost(pCur);
|
|
pCur->atLast = rc==SQLITE_OK ?1:0;
|
|
}
|
|
}
|
|
return rc;
|
|
}
|
|
|
|
#include <ctype.h>
|
|
|
|
void hexdump(FILE *fout, int buflen, void *ptr) {
|
|
unsigned char *buf = (unsigned char*)ptr;
|
|
int i, j;
|
|
for (i=0; i<buflen; i+=32) {
|
|
fprintf(fout, "%06x: ", i);
|
|
for (j=0; j<32; j++) {
|
|
if(j == 16)
|
|
fprintf(fout, " ");
|
|
if (i+j < buflen)
|
|
fprintf(fout, "%02x ", buf[i+j]);
|
|
else
|
|
fprintf(fout, " ");
|
|
}
|
|
fprintf(fout, " ");
|
|
for (j=0; j<32; j++) {
|
|
if(j == 16)
|
|
fprintf(fout, " ");
|
|
if (i+j < buflen)
|
|
fprintf(fout, "%c", isprint(buf[i+j]) ? buf[i+j] : '.');
|
|
}
|
|
fprintf(fout, "\n");
|
|
}
|
|
}
|
|
|
|
/* Move the cursor so that it points to an entry near the key
|
|
** specified by pIdxKey or intKey. Return a success code.
|
|
**
|
|
** For INTKEY tables, the intKey parameter is used. pIdxKey
|
|
** must be NULL. For index tables, pIdxKey is used and intKey
|
|
** is ignored.
|
|
**
|
|
** If an exact match is not found, then the cursor is always
|
|
** left pointing at a leaf page which would hold the entry if it
|
|
** were present. The cursor might point to an entry that comes
|
|
** before or after the key.
|
|
**
|
|
** An integer is written into *pRes which is the result of
|
|
** comparing the key with the entry to which the cursor is
|
|
** pointing. The meaning of the integer written into
|
|
** *pRes is as follows:
|
|
**
|
|
** *pRes<0 The cursor is left pointing at an entry that
|
|
** is smaller than intKey/pIdxKey or if the table is empty
|
|
** and the cursor is therefore left point to nothing.
|
|
**
|
|
** *pRes==0 The cursor is left pointing at an entry that
|
|
** exactly matches intKey/pIdxKey.
|
|
**
|
|
** *pRes>0 The cursor is left pointing at an entry that
|
|
** is larger than intKey/pIdxKey.
|
|
**
|
|
*/
|
|
SQLITE_PRIVATE int sqlite3BtreeMovetoUnpacked(
|
|
BtCursor *pCur, /* The cursor to be moved */
|
|
UnpackedRecord *pIdxKey, /* Unpacked index key */
|
|
i64 intKey, /* The table key */
|
|
int biasRight, /* If true, bias the search to the high end */
|
|
int *pRes /* Write search results here */
|
|
){
|
|
int rc;
|
|
|
|
assert( cursorHoldsMutex(pCur) );
|
|
assert( sqlite3_mutex_held(pCur->pBtree->db->mutex) );
|
|
assert( pRes );
|
|
assert( (pIdxKey==0)==(pCur->pKeyInfo==0) );
|
|
|
|
/* If the cursor is already positioned at the point we are trying
|
|
** to move to, then just return without doing any work */
|
|
if( pCur->eState==CURSOR_VALID && pCur->validNKey
|
|
&& pCur->apPage[0]->intKey
|
|
){
|
|
if( pCur->info.nKey==intKey ){
|
|
*pRes = 0;
|
|
return SQLITE_OK;
|
|
}
|
|
if( pCur->atLast && pCur->info.nKey<intKey ){
|
|
*pRes = -1;
|
|
return SQLITE_OK;
|
|
}
|
|
}
|
|
|
|
rc = moveToRoot(pCur);
|
|
if( rc ){
|
|
return rc;
|
|
}
|
|
assert( pCur->apPage[pCur->iPage] );
|
|
assert( pCur->apPage[pCur->iPage]->isInit );
|
|
assert( pCur->apPage[pCur->iPage]->nCell>0 || pCur->eState==CURSOR_INVALID );
|
|
if( pCur->eState==CURSOR_INVALID ){
|
|
*pRes = -1;
|
|
assert( pCur->apPage[pCur->iPage]->nCell==0 );
|
|
return SQLITE_OK;
|
|
}
|
|
assert( pCur->apPage[0]->intKey || pIdxKey );
|
|
for(;;){
|
|
int lwr, upr;
|
|
Pgno chldPg;
|
|
MemPage *pPage = pCur->apPage[pCur->iPage];
|
|
int c;
|
|
|
|
/* pPage->nCell must be greater than zero. If this is the root-page
|
|
** the cursor would have been Invalid above and this for(;;) loop
|
|
** not run. If this is not the root-page, then the moveToChild() routine
|
|
** would have already detected db corruption. Similarly, pPage must
|
|
** be the right kind (index or table) of b-tree page. Otherwise
|
|
** a moveToChild() or moveToRoot() call would have detected corruption. */
|
|
assert( pPage->nCell>0 );
|
|
assert( pPage->intKey==(pIdxKey==0) );
|
|
lwr = 0;
|
|
upr = pPage->nCell-1;
|
|
if( biasRight ){
|
|
pCur->aiIdx[pCur->iPage] = (u16)upr;
|
|
}else{
|
|
pCur->aiIdx[pCur->iPage] = (u16)((upr+lwr)/2);
|
|
}
|
|
for(;;){
|
|
int idx = pCur->aiIdx[pCur->iPage]; /* Index of current cell in pPage */
|
|
u8 *pCell; /* Pointer to current cell in pPage */
|
|
|
|
pCur->info.nSize = 0;
|
|
pCell = findCell(pPage, idx) + pPage->childPtrSize;
|
|
|
|
#if defined(__GNUC__) && defined(__linux__)
|
|
/* prefetch the next possible cells */
|
|
__builtin_prefetch(findCell(pPage, (u16)(((idx+1)+upr)/2)) + pPage->childPtrSize); /* c < 0 */
|
|
__builtin_prefetch(findCell(pPage, (u16)((lwr+(idx-1))/2)) + pPage->childPtrSize); /* c > 0 */
|
|
#endif
|
|
|
|
if( pPage->intKey ){
|
|
i64 nCellKey;
|
|
if( pPage->hasData ){
|
|
u32 dummy;
|
|
pCell += getVarint32(pCell, dummy);
|
|
}
|
|
getVarint(pCell, (u64*)&nCellKey);
|
|
if( nCellKey==intKey ){
|
|
c = 0;
|
|
}else if( nCellKey<intKey ){
|
|
c = -1;
|
|
}else{
|
|
assert( nCellKey>intKey );
|
|
c = +1;
|
|
}
|
|
pCur->validNKey = 1;
|
|
pCur->info.nKey = nCellKey;
|
|
}else{
|
|
/* The maximum supported page-size is 65536 bytes. This means that
|
|
** the maximum number of record bytes stored on an index B-Tree
|
|
** page is less than 16384 bytes and may be stored as a 2-byte
|
|
** varint. This information is used to attempt to avoid parsing
|
|
** the entire cell by checking for the cases where the record is
|
|
** stored entirely within the b-tree page by inspecting the first
|
|
** 2 bytes of the cell.
|
|
*/
|
|
int nCell = pCell[0];
|
|
if( !(nCell & 0x80) && nCell<=pPage->maxLocal ){
|
|
/* This branch runs if the record-size field of the cell is a
|
|
** single byte varint and the record fits entirely on the main
|
|
** b-tree page. */
|
|
c = sqlite3VdbeRecordCompare(nCell, (void*)&pCell[1], pIdxKey, 0, NULL);
|
|
}else if( !(pCell[1] & 0x80)
|
|
&& (nCell = ((nCell&0x7f)<<7) + pCell[1])<=pPage->maxLocal
|
|
){
|
|
/* The record-size field is a 2 byte varint and the record
|
|
** fits entirely on the main b-tree page. */
|
|
c = sqlite3VdbeRecordCompare(nCell, (void*)&pCell[2], pIdxKey, 0, NULL);
|
|
}else{
|
|
/* The record flows over onto one or more overflow pages. In
|
|
** this case the whole cell needs to be parsed, a buffer allocated
|
|
** and accessPayload() used to retrieve the record into the
|
|
** buffer before VdbeRecordCompare() can be called. */
|
|
|
|
/* pCellBody is pCell adjustd back to the start of the full cell */
|
|
u8 * const pCellBody = pCell - pPage->childPtrSize;
|
|
btreeParseCellPtr(pPage, pCellBody, &pCur->info);
|
|
|
|
/* OPTIMIZATION:
|
|
* Perhaps the comparison result can be determined from the partial record in pPage.
|
|
* Try the comparison with the partial record first. */
|
|
int nextStartField;
|
|
c = sqlite3VdbeRecordCompare(pCur->info.nLocal, pCur->info.pCell + pCur->info.nHeader, pIdxKey, 0, &nextStartField);
|
|
|
|
/* If c is 0 and startField is valid then we must load more record data (we'll load all of it) */
|
|
int moreDataRequired = (c == 0 && nextStartField >= 0);
|
|
|
|
/* Change this to nonzero to force full comparisons and verify partial comparison result */
|
|
#define SQLITE3_BTREE_FORCE_FULL_COMPARISONS 0
|
|
|
|
if(moreDataRequired || SQLITE3_BTREE_FORCE_FULL_COMPARISONS) {
|
|
/* Load the entire cell payload */
|
|
nCell = (int)pCur->info.nKey;
|
|
void *pCellKey = sqlite3Malloc( nCell );
|
|
if( pCellKey==0 ){
|
|
rc = SQLITE_NOMEM;
|
|
goto moveto_finish;
|
|
}
|
|
rc = accessPayload(pCur, 0, nCell, (unsigned char*)pCellKey, 0);
|
|
if( rc ){
|
|
sqlite3_free(pCellKey);
|
|
goto moveto_finish;
|
|
}
|
|
|
|
#if SQLITE3_BTREE_FORCE_FULL_COMPARISONS
|
|
int partial_c = c;
|
|
#endif
|
|
c = sqlite3VdbeRecordCompare(nCell, pCellKey, pIdxKey, (SQLITE3_BTREE_FORCE_FULL_COMPARISONS ? 0 : nextStartField), NULL);
|
|
|
|
#if SQLITE3_BTREE_FORCE_FULL_COMPARISONS
|
|
/* If more data was NOT required but the partial comparison produced a different result than full
|
|
* then something is wrong, log stuff and abort */
|
|
if(!moreDataRequired && partial_c != c) {
|
|
fprintf(stderr, "MISMATCH c=%d partial=%d\n", c, partial_c);
|
|
fprintf(stderr, "SHORT BUFFER size=%d\n", pCur->info.nLocal);
|
|
hexdump(stderr, pCur->info.nLocal, pCur->info.pCell + pCur->info.nHeader);
|
|
fprintf(stderr, "FULL BUFFER size=%d\n", nCell);
|
|
hexdump(stderr, nCell, pCellKey);
|
|
assert(0);
|
|
}
|
|
#endif
|
|
|
|
sqlite3_free(pCellKey);
|
|
} else {
|
|
//printf("+");
|
|
}
|
|
}
|
|
}
|
|
if( c==0 ){
|
|
if( pPage->intKey && !pPage->leaf ){
|
|
lwr = idx;
|
|
upr = lwr - 1;
|
|
break;
|
|
}else{
|
|
*pRes = 0;
|
|
rc = SQLITE_OK;
|
|
goto moveto_finish;
|
|
}
|
|
}
|
|
if( c<0 ){
|
|
lwr = idx+1;
|
|
}else{
|
|
upr = idx-1;
|
|
}
|
|
if( lwr>upr ){
|
|
break;
|
|
}
|
|
pCur->aiIdx[pCur->iPage] = (u16)((lwr+upr)/2);
|
|
}
|
|
assert( lwr==upr+1 );
|
|
assert( pPage->isInit );
|
|
if( pPage->leaf ){
|
|
chldPg = 0;
|
|
}else if( lwr>=pPage->nCell ){
|
|
chldPg = get4byte(&pPage->aData[pPage->hdrOffset+8]);
|
|
}else{
|
|
chldPg = get4byte(findCell(pPage, lwr));
|
|
}
|
|
if( chldPg==0 ){
|
|
assert( pCur->aiIdx[pCur->iPage]<pCur->apPage[pCur->iPage]->nCell );
|
|
*pRes = c;
|
|
rc = SQLITE_OK;
|
|
goto moveto_finish;
|
|
}
|
|
pCur->aiIdx[pCur->iPage] = (u16)lwr;
|
|
pCur->info.nSize = 0;
|
|
pCur->validNKey = 0;
|
|
rc = moveToChild(pCur, chldPg);
|
|
if( rc ) goto moveto_finish;
|
|
}
|
|
moveto_finish:
|
|
return rc;
|
|
}
|
|
|
|
|
|
/*
|
|
** Return TRUE if the cursor is not pointing at an entry of the table.
|
|
**
|
|
** TRUE will be returned after a call to sqlite3BtreeNext() moves
|
|
** past the last entry in the table or sqlite3BtreePrev() moves past
|
|
** the first entry. TRUE is also returned if the table is empty.
|
|
*/
|
|
SQLITE_PRIVATE int sqlite3BtreeEof(BtCursor *pCur){
|
|
/* TODO: What if the cursor is in CURSOR_REQUIRESEEK but all table entries
|
|
** have been deleted? This API will need to change to return an error code
|
|
** as well as the boolean result value.
|
|
*/
|
|
return (CURSOR_VALID!=pCur->eState);
|
|
}
|
|
|
|
/*
|
|
** Advance the cursor to the next entry in the database. If
|
|
** successful then set *pRes=0. If the cursor
|
|
** was already pointing to the last entry in the database before
|
|
** this routine was called, then set *pRes=1.
|
|
*/
|
|
SQLITE_PRIVATE int sqlite3BtreeNext(BtCursor *pCur, int *pRes){
|
|
int rc;
|
|
int idx;
|
|
MemPage *pPage;
|
|
|
|
assert( cursorHoldsMutex(pCur) );
|
|
rc = restoreCursorPosition(pCur);
|
|
if( rc!=SQLITE_OK ){
|
|
return rc;
|
|
}
|
|
assert( pRes!=0 );
|
|
if( CURSOR_INVALID==pCur->eState ){
|
|
*pRes = 1;
|
|
return SQLITE_OK;
|
|
}
|
|
if( pCur->skipNext>0 ){
|
|
pCur->skipNext = 0;
|
|
*pRes = 0;
|
|
return SQLITE_OK;
|
|
}
|
|
pCur->skipNext = 0;
|
|
|
|
pPage = pCur->apPage[pCur->iPage];
|
|
idx = ++pCur->aiIdx[pCur->iPage];
|
|
assert( pPage->isInit );
|
|
assert( idx<=pPage->nCell );
|
|
|
|
pCur->info.nSize = 0;
|
|
pCur->validNKey = 0;
|
|
if( idx>=pPage->nCell ){
|
|
if( !pPage->leaf ){
|
|
rc = moveToChild(pCur, get4byte(&pPage->aData[pPage->hdrOffset+8]));
|
|
if( rc ) return rc;
|
|
rc = moveToLeftmost(pCur);
|
|
*pRes = 0;
|
|
return rc;
|
|
}
|
|
do{
|
|
if( pCur->iPage==0 ){
|
|
*pRes = 1;
|
|
pCur->eState = CURSOR_INVALID;
|
|
return SQLITE_OK;
|
|
}
|
|
moveToParent(pCur);
|
|
pPage = pCur->apPage[pCur->iPage];
|
|
}while( pCur->aiIdx[pCur->iPage]>=pPage->nCell );
|
|
*pRes = 0;
|
|
if( pPage->intKey ){
|
|
rc = sqlite3BtreeNext(pCur, pRes);
|
|
}else{
|
|
rc = SQLITE_OK;
|
|
}
|
|
return rc;
|
|
}
|
|
*pRes = 0;
|
|
if( pPage->leaf ){
|
|
return SQLITE_OK;
|
|
}
|
|
rc = moveToLeftmost(pCur);
|
|
return rc;
|
|
}
|
|
|
|
|
|
/*
|
|
** Step the cursor to the back to the previous entry in the database. If
|
|
** successful then set *pRes=0. If the cursor
|
|
** was already pointing to the first entry in the database before
|
|
** this routine was called, then set *pRes=1.
|
|
*/
|
|
SQLITE_PRIVATE int sqlite3BtreePrevious(BtCursor *pCur, int *pRes){
|
|
int rc;
|
|
MemPage *pPage;
|
|
|
|
assert( cursorHoldsMutex(pCur) );
|
|
rc = restoreCursorPosition(pCur);
|
|
if( rc!=SQLITE_OK ){
|
|
return rc;
|
|
}
|
|
pCur->atLast = 0;
|
|
if( CURSOR_INVALID==pCur->eState ){
|
|
*pRes = 1;
|
|
return SQLITE_OK;
|
|
}
|
|
if( pCur->skipNext<0 ){
|
|
pCur->skipNext = 0;
|
|
*pRes = 0;
|
|
return SQLITE_OK;
|
|
}
|
|
pCur->skipNext = 0;
|
|
|
|
pPage = pCur->apPage[pCur->iPage];
|
|
assert( pPage->isInit );
|
|
if( !pPage->leaf ){
|
|
int idx = pCur->aiIdx[pCur->iPage];
|
|
rc = moveToChild(pCur, get4byte(findCell(pPage, idx)));
|
|
if( rc ){
|
|
return rc;
|
|
}
|
|
rc = moveToRightmost(pCur);
|
|
}else{
|
|
while( pCur->aiIdx[pCur->iPage]==0 ){
|
|
if( pCur->iPage==0 ){
|
|
pCur->eState = CURSOR_INVALID;
|
|
*pRes = 1;
|
|
return SQLITE_OK;
|
|
}
|
|
moveToParent(pCur);
|
|
}
|
|
pCur->info.nSize = 0;
|
|
pCur->validNKey = 0;
|
|
|
|
pCur->aiIdx[pCur->iPage]--;
|
|
pPage = pCur->apPage[pCur->iPage];
|
|
if( pPage->intKey && !pPage->leaf ){
|
|
rc = sqlite3BtreePrevious(pCur, pRes);
|
|
}else{
|
|
rc = SQLITE_OK;
|
|
}
|
|
}
|
|
*pRes = 0;
|
|
return rc;
|
|
}
|
|
|
|
/*
|
|
** Allocate a new page from the database file.
|
|
**
|
|
** The new page is marked as dirty. (In other words, sqlite3PagerWrite()
|
|
** has already been called on the new page.) The new page has also
|
|
** been referenced and the calling routine is responsible for calling
|
|
** sqlite3PagerUnref() on the new page when it is done.
|
|
**
|
|
** SQLITE_OK is returned on success. Any other return value indicates
|
|
** an error. *ppPage and *pPgno are undefined in the event of an error.
|
|
** Do not invoke sqlite3PagerUnref() on *ppPage if an error is returned.
|
|
**
|
|
** If the "nearby" parameter is not 0, then a (feeble) effort is made to
|
|
** locate a page close to the page number "nearby". This can be used in an
|
|
** attempt to keep related pages close to each other in the database file,
|
|
** which in turn can make database access faster.
|
|
**
|
|
** If the "exact" parameter is not 0, and the page-number nearby exists
|
|
** anywhere on the free-list, then it is guaranteed to be returned.
|
|
**
|
|
** The original comment in the vendor sqlite source said
|
|
** "[the "exact" parameter] is only used by auto-vacuum databases when allocating a new table.
|
|
** In actuality, it is and was *also* used by incremental vacuum to allocate
|
|
** the last page of the file when it is a freelist page (now only when a trunk page)
|
|
*/
|
|
static int allocateBtreePage(
|
|
BtShared *pBt,
|
|
MemPage **ppPage,
|
|
Pgno *pPgno,
|
|
Pgno nearby,
|
|
u8 exact
|
|
){
|
|
MemPage *pPage1;
|
|
int rc;
|
|
u32 n; /* Number of pages on the freelist */
|
|
u32 k; /* Number of leaves on the trunk of the freelist */
|
|
MemPage *pTrunk = 0;
|
|
MemPage *pPrevTrunk = 0;
|
|
Pgno mxPage; /* Total size of the database file */
|
|
VVA_ONLY( int dbgTries=0 );
|
|
|
|
assert( sqlite3_mutex_held(pBt->mutex) );
|
|
pPage1 = pBt->pPage1;
|
|
mxPage = btreePagecount(pBt);
|
|
n = get4byte(&pPage1->aData[36]);
|
|
testcase( n==mxPage-1 );
|
|
if( n>=mxPage ){
|
|
return SQLITE_CORRUPT_BKPT;
|
|
}
|
|
if( n>0 ){
|
|
/* There are pages on the freelist. Reuse one of those pages. */
|
|
Pgno iTrunk = 0;
|
|
Pgno iPrevTrunk = 0;
|
|
u8 searchList = 0; /* If the free-list must be searched for 'nearby' */
|
|
u8 firstPassOrEmptiedTrunk = 1; /* Set to false after the first run through the free-list loop; set back to true by a special case below */
|
|
|
|
/* If the 'exact' parameter was true and a query of the pointer-map
|
|
** shows that the page 'nearby' is somewhere on the free-list, then
|
|
** the entire-list will be searched for that page.
|
|
*/
|
|
#ifndef SQLITE_OMIT_AUTOVACUUM
|
|
if( exact && nearby<=mxPage ){
|
|
u8 eType;
|
|
assert( nearby>0 );
|
|
assert( pBt->autoVacuum );
|
|
rc = ptrmapGet(pBt, nearby, &eType, &iTrunk);
|
|
if( rc ) return rc;
|
|
|
|
if (eType == PTRMAP_FREEPAGE) {
|
|
/* If the ptr map for the free page had a pointer to its parent trunk, then
|
|
** we can skip ahead in the list.
|
|
**/
|
|
if( iTrunk>mxPage ){
|
|
rc = SQLITE_CORRUPT_BKPT;
|
|
}
|
|
else if( iTrunk!=0 ){
|
|
rc = btreeGetPage(pBt, iTrunk, &pTrunk, 0);
|
|
}
|
|
else {
|
|
assert( !g_expect_full_pointermap || nearby == get4byte(&pPage1->aData[32]) );
|
|
}
|
|
if( rc ){
|
|
pTrunk = 0;
|
|
goto end_allocate_page;
|
|
}
|
|
}
|
|
|
|
if( eType==PTRMAP_FREEPAGE || eType==PTRMAP_FREELEAF ) {
|
|
searchList = 1;
|
|
}
|
|
*pPgno = nearby;
|
|
}
|
|
#endif
|
|
|
|
/* Decrement the free-list count by 1. Set iTrunk to the index of the
|
|
** first free-list trunk page. iPrevTrunk is initially 1.
|
|
*/
|
|
rc = sqlite3PagerWrite(pPage1->pDbPage);
|
|
if( rc ) return rc;
|
|
put4byte(&pPage1->aData[36], n-1);
|
|
|
|
/* If we are searching the list, and we have full 3.0 augmented pointer map data, this
|
|
** loop will execute only once because we are starting with pTrunk pointing to the trunk
|
|
** page immediately before the trunk page we are searching for.
|
|
**
|
|
** If we are not searching the list, the loop will normally run only once, but may
|
|
** run a second time (by setting firstPassOrEmptiedTrunk=1) if the first trunk page
|
|
** contained only truncated leaves (the second pass will then extract the trunk page
|
|
** itself as the allocated page).
|
|
**
|
|
** If we are searching the list and this is a legacy database with incomplete pointer map
|
|
** data, this loop may still have to scan the entire freelist until the page 'nearby' is
|
|
** located.
|
|
*/
|
|
while( searchList || firstPassOrEmptiedTrunk ) {
|
|
assert(!g_expect_full_pointermap || dbgTries++ < 2); // When we have full pointermap data, we should never iterate more than twice
|
|
firstPassOrEmptiedTrunk = 0;
|
|
pPrevTrunk = pTrunk;
|
|
iPrevTrunk = iTrunk;
|
|
if( pPrevTrunk ){
|
|
iTrunk = get4byte(&pPrevTrunk->aData[0]);
|
|
}else{
|
|
/* Set iTrunk to the index of the first free-list trunk page. */
|
|
iTrunk = get4byte(&pPage1->aData[32]);
|
|
}
|
|
testcase( iTrunk==mxPage );
|
|
if( iTrunk>mxPage ){
|
|
rc = SQLITE_CORRUPT_BKPT;
|
|
}else{
|
|
rc = btreeGetPage(pBt, iTrunk, &pTrunk, 0);
|
|
}
|
|
if( rc ){
|
|
pTrunk = 0;
|
|
goto end_allocate_page;
|
|
}
|
|
|
|
k = get4byte(&pTrunk->aData[4]);
|
|
const int origNumLeaves = k;
|
|
|
|
if( k==0 && !searchList ){
|
|
/* The trunk has no leaves and the list is not being searched.
|
|
** So extract the trunk page itself and use it as the newly
|
|
** allocated page */
|
|
assert( pPrevTrunk==0 );
|
|
rc = sqlite3PagerWrite(pTrunk->pDbPage);
|
|
if( rc ){
|
|
goto end_allocate_page;
|
|
}
|
|
*pPgno = iTrunk;
|
|
memcpy(&pPage1->aData[32], &pTrunk->aData[0], 4);
|
|
|
|
Pgno iNextTrunk = get4byte(&pTrunk->aData[0]);
|
|
if( iNextTrunk!=0 ){
|
|
ptrmapPut(pBt, iNextTrunk, PTRMAP_FREEPAGE, 0, &rc); // We aren't searching the list, so are at the beginning of the list, so there is no previous trunk
|
|
if( rc!=SQLITE_OK ){
|
|
goto end_allocate_page;
|
|
}
|
|
}
|
|
|
|
*ppPage = pTrunk;
|
|
pTrunk = 0;
|
|
TRACE(("ALLOCATE: %d trunk - %d free pages left\n", *pPgno, n-1));
|
|
}else if( k>(u32)(pBt->usableSize/4 - 2) ){
|
|
/* Value of k is out of range. Database corruption */
|
|
rc = SQLITE_CORRUPT_BKPT;
|
|
goto end_allocate_page;
|
|
#ifndef SQLITE_OMIT_AUTOVACUUM
|
|
}else if( searchList && nearby==iTrunk ){
|
|
/* The list is being searched and this trunk page is the page
|
|
** to allocate, regardless of whether it has leaves.
|
|
*/
|
|
assert( *pPgno==iTrunk );
|
|
Pgno iNextTrunk = get4byte(&pTrunk->aData[0]);
|
|
*ppPage = pTrunk;
|
|
searchList = 0;
|
|
rc = sqlite3PagerWrite(pTrunk->pDbPage);
|
|
if( rc ){
|
|
goto end_allocate_page;
|
|
}
|
|
if( k>0 ){
|
|
/* The trunk page is required by the caller but it contains
|
|
** pointers to free-list leaves. The last (non-truncated) leaf becomes a trunk
|
|
** page in this case.
|
|
*/
|
|
MemPage *pNewTrunk;
|
|
Pgno iNewTrunk;
|
|
// Find the last leaf page that isn't already truncated (beyond EOF)
|
|
do {
|
|
iNewTrunk = get4byte(&pTrunk->aData[8 + (origNumLeaves-k)*4]);
|
|
} while(iNewTrunk > mxPage && --k > 0);
|
|
|
|
if( k>0 ) {
|
|
if( iNewTrunk>mxPage ){
|
|
rc = SQLITE_CORRUPT_BKPT;
|
|
goto end_allocate_page;
|
|
}
|
|
testcase( iNewTrunk==mxPage );
|
|
|
|
/* If iNewTrunk was previously a PTRMAP_FREELEAF, it needs to
|
|
** be changed to a PTRMAP_FREEPAGE */
|
|
ptrmapPut(pBt, iNewTrunk, PTRMAP_FREEPAGE, iPrevTrunk, &rc);
|
|
if( rc!=SQLITE_OK ){
|
|
goto end_allocate_page;
|
|
}
|
|
|
|
if( iNextTrunk!=0 ) {
|
|
ptrmapPut(pBt, iNextTrunk, PTRMAP_FREEPAGE, iNewTrunk, &rc);
|
|
if( rc!=SQLITE_OK ){
|
|
goto end_allocate_page;
|
|
}
|
|
}
|
|
|
|
rc = btreeGetPage(pBt, iNewTrunk, &pNewTrunk, 0);
|
|
if( rc!=SQLITE_OK ){
|
|
goto end_allocate_page;
|
|
}
|
|
rc = sqlite3PagerWrite(pNewTrunk->pDbPage);
|
|
if( rc!=SQLITE_OK ){
|
|
releasePage(pNewTrunk);
|
|
goto end_allocate_page;
|
|
}
|
|
memcpy(&pNewTrunk->aData[0], &pTrunk->aData[0], 4);
|
|
put4byte(&pNewTrunk->aData[4], k-1);
|
|
memcpy(&pNewTrunk->aData[8], &pTrunk->aData[12+(origNumLeaves-k)*4], (k-1)*4);
|
|
releasePage(pNewTrunk);
|
|
if( !pPrevTrunk ){
|
|
assert( sqlite3PagerIswriteable(pPage1->pDbPage) );
|
|
put4byte(&pPage1->aData[32], iNewTrunk);
|
|
}else{
|
|
rc = sqlite3PagerWrite(pPrevTrunk->pDbPage);
|
|
if( rc ){
|
|
goto end_allocate_page;
|
|
}
|
|
put4byte(&pPrevTrunk->aData[0], iNewTrunk);
|
|
}
|
|
}
|
|
}
|
|
if( k==0 ){
|
|
// All of the leaves in the trunk were already truncated / beyond EOF
|
|
// So we can just unlink the trunk and allocate it; there is no data left in it
|
|
// that needs to go somewhere else
|
|
if( iNextTrunk!=0 ){
|
|
ptrmapPut(pBt, iNextTrunk, PTRMAP_FREEPAGE, iPrevTrunk, &rc);
|
|
if( rc!=SQLITE_OK ){
|
|
goto end_allocate_page;
|
|
}
|
|
}
|
|
|
|
if( !pPrevTrunk ){
|
|
memcpy(&pPage1->aData[32], &pTrunk->aData[0], 4);
|
|
}else{
|
|
rc = sqlite3PagerWrite(pPrevTrunk->pDbPage);
|
|
if( rc!=SQLITE_OK ){
|
|
goto end_allocate_page;
|
|
}
|
|
memcpy(&pPrevTrunk->aData[0], &pTrunk->aData[0], 4);
|
|
}
|
|
}
|
|
pTrunk = 0;
|
|
TRACE(("ALLOCATE: %d trunk - %d free pages left\n", *pPgno, n-1));
|
|
#endif
|
|
}else if( k>0 ){
|
|
/* Extract a leaf from the trunk */
|
|
u32 closest;
|
|
Pgno iPage;
|
|
unsigned char *aData = pTrunk->aData;
|
|
rc = sqlite3PagerWrite(pTrunk->pDbPage);
|
|
if( rc ){
|
|
goto end_allocate_page;
|
|
}
|
|
|
|
u32 i=0;
|
|
int dist=-1;
|
|
Pgno leaf;
|
|
|
|
while( i<k ) {
|
|
// Find the last leaf which isn't truncated (beyond EOF)
|
|
// While we are at it, compact the remaining pages
|
|
leaf = get4byte(&aData[8+i*4]);
|
|
while( leaf>mxPage && --k>i ) {
|
|
leaf = get4byte(&aData[8+k*4]);
|
|
if( leaf<=mxPage )
|
|
put4byte(&aData[8+i*4], leaf);
|
|
}
|
|
|
|
if( leaf <= mxPage ){
|
|
int d2 = sqlite3AbsInt32(leaf - nearby);
|
|
if( dist<0 || d2<dist ) {
|
|
closest = i;
|
|
iPage = leaf;
|
|
dist = d2;
|
|
}
|
|
}
|
|
|
|
/* If we found our page exactly or we aren't doing a nearby search,
|
|
** then we can quit looking.
|
|
*/
|
|
if( !nearby || dist==0 )
|
|
break;
|
|
|
|
++i;
|
|
}
|
|
|
|
if( k==0 ){
|
|
/* All the leaves have been truncated. If !searchList, then we want
|
|
** to use this trunk as our free page. Otherwise, keep looking in
|
|
** the next trunk.
|
|
**
|
|
** TODO: collapse this trunk into a neighbor if searchList?
|
|
*/
|
|
put4byte(&aData[4], 0);
|
|
if( !searchList ) {
|
|
releasePage(pTrunk);
|
|
pTrunk = pPrevTrunk;
|
|
iTrunk = iPrevTrunk; // not actually used, but maintain the invariant
|
|
firstPassOrEmptiedTrunk = 1; // goto the case `k==0 && !searchList` above to finish the job
|
|
}
|
|
} else {
|
|
testcase( iPage==mxPage );
|
|
if( iPage>mxPage ){
|
|
rc = SQLITE_CORRUPT_BKPT;
|
|
goto end_allocate_page;
|
|
}
|
|
testcase( iPage==mxPage );
|
|
if( !searchList || iPage==nearby ){
|
|
int noContent;
|
|
*pPgno = iPage;
|
|
TRACE(("ALLOCATE: %d was leaf %d of %d on trunk %d"
|
|
": %d more free pages\n",
|
|
*pPgno, closest+1, k, pTrunk->pgno, n-1));
|
|
if( closest<k-1 ){
|
|
memcpy(&aData[8+closest*4], &aData[4+k*4], 4);
|
|
}
|
|
put4byte(&aData[4], k-1);
|
|
assert( sqlite3PagerIswriteable(pTrunk->pDbPage) );
|
|
noContent = !btreeGetHasContent(pBt, *pPgno);
|
|
rc = btreeGetPage(pBt, *pPgno, ppPage, noContent);
|
|
if( rc==SQLITE_OK ){
|
|
rc = sqlite3PagerWrite((*ppPage)->pDbPage);
|
|
if( rc!=SQLITE_OK ){
|
|
releasePage(*ppPage);
|
|
}
|
|
}
|
|
searchList = 0;
|
|
}else if(k < origNumLeaves){
|
|
put4byte(&aData[4], k);
|
|
}
|
|
}
|
|
}
|
|
releasePage(pPrevTrunk);
|
|
pPrevTrunk = 0;
|
|
}
|
|
} else {
|
|
/* There are no pages on the freelist, so create a new page at the
|
|
** end of the file */
|
|
rc = sqlite3PagerWrite(pBt->pPage1->pDbPage);
|
|
if( rc ) return rc;
|
|
pBt->nPage++;
|
|
if( pBt->nPage==PENDING_BYTE_PAGE(pBt) ) pBt->nPage++;
|
|
|
|
#ifndef SQLITE_OMIT_AUTOVACUUM
|
|
if( pBt->autoVacuum && PTRMAP_ISPAGE(pBt, pBt->nPage) ){
|
|
/* If *pPgno refers to a pointer-map page, allocate two new pages
|
|
** at the end of the file instead of one. The first allocated page
|
|
** becomes a new pointer-map page, the second is used by the caller.
|
|
*/
|
|
MemPage *pPg = 0;
|
|
TRACE(("ALLOCATE: %d from end of file (pointer-map page)\n", pBt->nPage));
|
|
assert( pBt->nPage!=PENDING_BYTE_PAGE(pBt) );
|
|
rc = btreeGetPage(pBt, pBt->nPage, &pPg, 1);
|
|
if( rc==SQLITE_OK ){
|
|
rc = sqlite3PagerWrite(pPg->pDbPage);
|
|
releasePage(pPg);
|
|
}
|
|
if( rc ) return rc;
|
|
pBt->nPage++;
|
|
if( pBt->nPage==PENDING_BYTE_PAGE(pBt) ){ pBt->nPage++; }
|
|
}
|
|
#endif
|
|
put4byte(28 + (u8*)pBt->pPage1->aData, pBt->nPage);
|
|
*pPgno = pBt->nPage;
|
|
|
|
assert( *pPgno!=PENDING_BYTE_PAGE(pBt) );
|
|
rc = btreeGetPage(pBt, *pPgno, ppPage, 1);
|
|
if( rc ) return rc;
|
|
rc = sqlite3PagerWrite((*ppPage)->pDbPage);
|
|
if( rc!=SQLITE_OK ){
|
|
releasePage(*ppPage);
|
|
}
|
|
TRACE(("ALLOCATE: %d from end of file\n", *pPgno));
|
|
}
|
|
|
|
assert( *pPgno!=PENDING_BYTE_PAGE(pBt) );
|
|
|
|
end_allocate_page:
|
|
releasePage(pTrunk);
|
|
releasePage(pPrevTrunk);
|
|
if( rc==SQLITE_OK ){
|
|
if( sqlite3PagerPageRefcount((*ppPage)->pDbPage)>1 ){
|
|
releasePage(*ppPage);
|
|
return SQLITE_CORRUPT_BKPT;
|
|
}
|
|
(*ppPage)->isInit = 0;
|
|
}else{
|
|
*ppPage = 0;
|
|
}
|
|
return rc;
|
|
}
|
|
|
|
/*
|
|
** This function is used to add page iPage to the database file free-list.
|
|
** It is assumed that the page is not already a part of the free-list.
|
|
**
|
|
** The value passed as the second argument to this function is optional.
|
|
** If the caller happens to have a pointer to the MemPage object
|
|
** corresponding to page iPage handy, it may pass it as the second value.
|
|
** Otherwise, it may pass NULL.
|
|
**
|
|
** If a pointer to a MemPage object is passed as the second argument,
|
|
** its reference count is not altered by this function.
|
|
*/
|
|
static int freePage2(BtShared *pBt, MemPage *pMemPage, Pgno iPage){
|
|
MemPage *pTrunk = 0; /* Free-list trunk page */
|
|
Pgno iTrunk = 0; /* Page number of free-list trunk page */
|
|
MemPage *pPage1 = pBt->pPage1; /* Local reference to page 1 */
|
|
MemPage *pPage; /* Page being freed. May be NULL. */
|
|
int rc; /* Return Code */
|
|
int nFree; /* Initial number of pages on free-list */
|
|
|
|
assert( sqlite3_mutex_held(pBt->mutex) );
|
|
assert( iPage>1 );
|
|
assert( !pMemPage || pMemPage->pgno==iPage );
|
|
|
|
if( pMemPage ){
|
|
pPage = pMemPage;
|
|
sqlite3PagerRef(pPage->pDbPage);
|
|
}else{
|
|
pPage = btreePageLookup(pBt, iPage);
|
|
}
|
|
|
|
/* Increment the free page count on pPage1 */
|
|
rc = sqlite3PagerWrite(pPage1->pDbPage);
|
|
if( rc ) goto freepage_out;
|
|
nFree = get4byte(&pPage1->aData[36]);
|
|
put4byte(&pPage1->aData[36], nFree+1);
|
|
|
|
if( pBt->secureDelete ){
|
|
/* If the secure_delete option is enabled, then
|
|
** always fully overwrite deleted information with zeros.
|
|
*/
|
|
if( (!pPage && ((rc = btreeGetPage(pBt, iPage, &pPage, 0))!=0) )
|
|
|| ((rc = sqlite3PagerWrite(pPage->pDbPage))!=0)
|
|
){
|
|
goto freepage_out;
|
|
}
|
|
memset(pPage->aData, 0, pPage->pBt->pageSize);
|
|
}
|
|
|
|
/* If the database supports auto-vacuum, write an entry in the pointer-map
|
|
** to indicate that the page is free.
|
|
*/
|
|
if( ISAUTOVACUUM ){
|
|
ptrmapPut(pBt, iPage, PTRMAP_FREEPAGE, 0, &rc);
|
|
if( rc ) goto freepage_out;
|
|
}
|
|
|
|
/* Now manipulate the actual database free-list structure. There are two
|
|
** possibilities. If the free-list is currently empty, or if the first
|
|
** trunk page in the free-list is full, then this page will become a
|
|
** new free-list trunk page. Otherwise, it will become a leaf of the
|
|
** first trunk page in the current free-list. This block tests if it
|
|
** is possible to add the page as a new free-list leaf.
|
|
*/
|
|
if( nFree!=0 ){
|
|
u32 nLeaf; /* Initial number of leaf cells on trunk page */
|
|
|
|
iTrunk = get4byte(&pPage1->aData[32]);
|
|
rc = btreeGetPage(pBt, iTrunk, &pTrunk, 0);
|
|
if( rc!=SQLITE_OK ){
|
|
goto freepage_out;
|
|
}
|
|
|
|
nLeaf = get4byte(&pTrunk->aData[4]);
|
|
assert( pBt->usableSize>32 );
|
|
if( nLeaf > (u32)pBt->usableSize/4 - 2 ){
|
|
rc = SQLITE_CORRUPT_BKPT;
|
|
goto freepage_out;
|
|
}
|
|
if( nLeaf < (u32)pBt->usableSize/4 - 8 ){
|
|
/* In this case there is room on the trunk page to insert the page
|
|
** being freed as a new leaf.
|
|
**
|
|
** Note that the trunk page is not really full until it contains
|
|
** usableSize/4 - 2 entries, not usableSize/4 - 8 entries as we have
|
|
** coded. But due to a coding error in versions of SQLite prior to
|
|
** 3.6.0, databases with freelist trunk pages holding more than
|
|
** usableSize/4 - 8 entries will be reported as corrupt. In order
|
|
** to maintain backwards compatibility with older versions of SQLite,
|
|
** we will continue to restrict the number of entries to usableSize/4 - 8
|
|
** for now. At some point in the future (once everyone has upgraded
|
|
** to 3.6.0 or later) we should consider fixing the conditional above
|
|
** to read "usableSize/4-2" instead of "usableSize/4-8".
|
|
*/
|
|
rc = sqlite3PagerWrite(pTrunk->pDbPage);
|
|
if( rc==SQLITE_OK ){
|
|
put4byte(&pTrunk->aData[4], nLeaf+1);
|
|
put4byte(&pTrunk->aData[8+nLeaf*4], iPage);
|
|
if( pPage && !pBt->secureDelete ){
|
|
sqlite3PagerDontWrite(pPage->pDbPage);
|
|
}
|
|
rc = btreeSetHasContent(pBt, iPage);
|
|
}
|
|
|
|
/* We know this entry is a leaf, so mark it as such in the PTRMAP */
|
|
if( ISAUTOVACUUM ){
|
|
ptrmapPut(pBt, iPage, PTRMAP_FREELEAF, 0, &rc);
|
|
if( rc ) goto freepage_out;
|
|
}
|
|
|
|
TRACE(("FREE-PAGE: %d leaf on trunk page %d\n",pPage->pgno,pTrunk->pgno));
|
|
goto freepage_out;
|
|
}
|
|
}
|
|
|
|
/* If control flows to this point, then it was not possible to add the
|
|
** the page being freed as a leaf page of the first trunk in the free-list.
|
|
** Possibly because the free-list is empty, or possibly because the
|
|
** first trunk in the free-list is full. Either way, the page being freed
|
|
** will become the new first trunk page in the free-list.
|
|
*/
|
|
if( pPage==0 && SQLITE_OK!=(rc = btreeGetPage(pBt, iPage, &pPage, 0)) ){
|
|
goto freepage_out;
|
|
}
|
|
rc = sqlite3PagerWrite(pPage->pDbPage);
|
|
if( rc!=SQLITE_OK ){
|
|
goto freepage_out;
|
|
}
|
|
put4byte(pPage->aData, iTrunk);
|
|
put4byte(&pPage->aData[4], 0);
|
|
put4byte(&pPage1->aData[32], iPage);
|
|
|
|
/* The previous head of the free list should now point to the new
|
|
** head of the free list in the ptr map
|
|
*/
|
|
if( ISAUTOVACUUM && nFree>0 && iTrunk!=0 ){
|
|
ptrmapPut(pBt, iTrunk, PTRMAP_FREEPAGE, iPage, &rc);
|
|
if( rc ) goto freepage_out;
|
|
}
|
|
|
|
TRACE(("FREE-PAGE: %d new trunk page replacing %d\n", pPage->pgno, iTrunk));
|
|
|
|
freepage_out:
|
|
if( pPage ){
|
|
pPage->isInit = 0;
|
|
}
|
|
releasePage(pPage);
|
|
releasePage(pTrunk);
|
|
return rc;
|
|
}
|
|
static void freePage(MemPage *pPage, int *pRC){
|
|
if( (*pRC)==SQLITE_OK ){
|
|
*pRC = freePage2(pPage->pBt, pPage, pPage->pgno);
|
|
}
|
|
}
|
|
|
|
/*
|
|
** Free any overflow pages associated with the given Cell.
|
|
*/
|
|
static int clearCell(MemPage *pPage, unsigned char *pCell){
|
|
BtShared *pBt = pPage->pBt;
|
|
CellInfo info;
|
|
Pgno ovflPgno;
|
|
int rc;
|
|
int nOvfl;
|
|
u32 ovflPageSize;
|
|
|
|
assert( sqlite3_mutex_held(pPage->pBt->mutex) );
|
|
btreeParseCellPtr(pPage, pCell, &info);
|
|
if( info.iOverflow==0 ){
|
|
return SQLITE_OK; /* No overflow pages. Return without doing anything */
|
|
}
|
|
ovflPgno = get4byte(&pCell[info.iOverflow]);
|
|
Pgno ovflParent = pPage->pgno; // Expected parent of ovfl, to be verified before using the page
|
|
|
|
assert( pBt->usableSize > 4 );
|
|
ovflPageSize = pBt->usableSize - 4;
|
|
nOvfl = (info.nPayload - info.nLocal + ovflPageSize - 1)/ovflPageSize;
|
|
assert( ovflPgno==0 || nOvfl>0 );
|
|
while( nOvfl-- ){
|
|
// Validate link to overflow page before using it
|
|
rc = verifyParentChildLink(pBt, ovflParent, ovflPgno);
|
|
if(rc != SQLITE_OK)
|
|
return rc;
|
|
|
|
Pgno iNext = 0;
|
|
MemPage *pOvfl = 0;
|
|
if( ovflPgno<2 || ovflPgno>btreePagecount(pBt) ){
|
|
/* 0 is not a legal page number and page 1 cannot be an
|
|
** overflow page. Therefore if ovflPgno<2 or past the end of the
|
|
** file the database must be corrupt. */
|
|
return SQLITE_CORRUPT_BKPT;
|
|
}
|
|
if( nOvfl ){
|
|
rc = getOverflowPage(pBt, ovflPgno, &pOvfl, &iNext);
|
|
if( rc ) return rc;
|
|
}
|
|
|
|
if( ( pOvfl || ((pOvfl = btreePageLookup(pBt, ovflPgno))!=0) )
|
|
&& sqlite3PagerPageRefcount(pOvfl->pDbPage)!=1
|
|
){
|
|
/* There is no reason any cursor should have an outstanding reference
|
|
** to an overflow page belonging to a cell that is being deleted/updated.
|
|
** So if there exists more than one reference to this page, then it
|
|
** must not really be an overflow page and the database must be corrupt.
|
|
** It is helpful to detect this before calling freePage2(), as
|
|
** freePage2() may zero the page contents if secure-delete mode is
|
|
** enabled. If this 'overflow' page happens to be a page that the
|
|
** caller is iterating through or using in some other way, this
|
|
** can be problematic.
|
|
*/
|
|
rc = SQLITE_CORRUPT_BKPT;
|
|
}else{
|
|
rc = freePage2(pBt, pOvfl, ovflPgno);
|
|
}
|
|
|
|
if( pOvfl ){
|
|
sqlite3PagerUnref(pOvfl->pDbPage);
|
|
}
|
|
if( rc ) return rc;
|
|
ovflParent = ovflPgno;
|
|
ovflPgno = iNext;
|
|
}
|
|
return SQLITE_OK;
|
|
}
|
|
|
|
/*
|
|
** Create the byte sequence used to represent a cell on page pPage
|
|
** and write that byte sequence into pCell[]. Overflow pages are
|
|
** allocated and filled in as necessary. The calling procedure
|
|
** is responsible for making sure sufficient space has been allocated
|
|
** for pCell[].
|
|
**
|
|
** Note that pCell does not necessary need to point to the pPage->aData
|
|
** area. pCell might point to some temporary storage. The cell will
|
|
** be constructed in this temporary area then copied into pPage->aData
|
|
** later.
|
|
*/
|
|
static int fillInCell(
|
|
MemPage *pPage, /* The page that contains the cell */
|
|
unsigned char *pCell, /* Complete text of the cell */
|
|
const void *pKey, i64 nKey, /* The key */
|
|
const void *pData,int nData, /* The data */
|
|
int nZero, /* Extra zero bytes to append to pData */
|
|
int *pnSize /* Write cell size here */
|
|
){
|
|
int nPayload;
|
|
const u8 *pSrc;
|
|
int nSrc, n, rc;
|
|
int spaceLeft;
|
|
MemPage *pOvfl = 0;
|
|
MemPage *pToRelease = 0;
|
|
unsigned char *pPrior;
|
|
unsigned char *pPayload;
|
|
BtShared *pBt = pPage->pBt;
|
|
Pgno pgnoOvfl = 0;
|
|
int nHeader;
|
|
CellInfo info;
|
|
|
|
assert( sqlite3_mutex_held(pPage->pBt->mutex) );
|
|
|
|
/* pPage is not necessarily writeable since pCell might be auxiliary
|
|
** buffer space that is separate from the pPage buffer area */
|
|
assert( pCell<pPage->aData || pCell>=&pPage->aData[pBt->pageSize]
|
|
|| sqlite3PagerIswriteable(pPage->pDbPage) );
|
|
|
|
/* Fill in the header. */
|
|
nHeader = 0;
|
|
if( !pPage->leaf ){
|
|
nHeader += 4;
|
|
}
|
|
if( pPage->hasData ){
|
|
nHeader += putVarint(&pCell[nHeader], nData+nZero);
|
|
}else{
|
|
nData = nZero = 0;
|
|
}
|
|
nHeader += putVarint(&pCell[nHeader], *(u64*)&nKey);
|
|
btreeParseCellPtr(pPage, pCell, &info);
|
|
assert( info.nHeader==nHeader );
|
|
assert( info.nKey==nKey );
|
|
assert( info.nData==(u32)(nData+nZero) );
|
|
|
|
/* Fill in the payload */
|
|
nPayload = nData + nZero;
|
|
if( pPage->intKey ){
|
|
pSrc = pData;
|
|
nSrc = nData;
|
|
nData = 0;
|
|
}else{
|
|
if( NEVER(nKey>0x7fffffff || pKey==0) ){
|
|
return SQLITE_CORRUPT_BKPT;
|
|
}
|
|
nPayload += (int)nKey;
|
|
pSrc = pKey;
|
|
nSrc = (int)nKey;
|
|
}
|
|
*pnSize = info.nSize;
|
|
spaceLeft = info.nLocal;
|
|
pPayload = &pCell[nHeader];
|
|
pPrior = &pCell[info.iOverflow];
|
|
|
|
while( nPayload>0 ){
|
|
if( spaceLeft==0 ){
|
|
#ifndef SQLITE_OMIT_AUTOVACUUM
|
|
Pgno pgnoPtrmap = pgnoOvfl; /* Overflow page pointer-map entry page */
|
|
if( pBt->autoVacuum ){
|
|
do{
|
|
pgnoOvfl++;
|
|
} while(
|
|
PTRMAP_ISPAGE(pBt, pgnoOvfl) || pgnoOvfl==PENDING_BYTE_PAGE(pBt)
|
|
);
|
|
}
|
|
#endif
|
|
rc = allocateBtreePage(pBt, &pOvfl, &pgnoOvfl, pgnoOvfl, 0);
|
|
#ifndef SQLITE_OMIT_AUTOVACUUM
|
|
/* If the database supports auto-vacuum, and the second or subsequent
|
|
** overflow page is being allocated, add an entry to the pointer-map
|
|
** for that page now.
|
|
**
|
|
** If this is the first overflow page, then write a partial entry
|
|
** to the pointer-map. If we write nothing to this pointer-map slot,
|
|
** then the optimistic overflow chain processing in clearCell()
|
|
** may misinterpret the uninitialised values and delete the
|
|
** wrong pages from the database.
|
|
*/
|
|
if( pBt->autoVacuum && rc==SQLITE_OK ){
|
|
u8 eType = (pgnoPtrmap?PTRMAP_OVERFLOW2:PTRMAP_OVERFLOW1);
|
|
ptrmapPut(pBt, pgnoOvfl, eType, pgnoPtrmap, &rc);
|
|
if( rc ){
|
|
releasePage(pOvfl);
|
|
}
|
|
}
|
|
#endif
|
|
if( rc ){
|
|
releasePage(pToRelease);
|
|
return rc;
|
|
}
|
|
|
|
/* If pToRelease is not zero than pPrior points into the data area
|
|
** of pToRelease. Make sure pToRelease is still writeable. */
|
|
assert( pToRelease==0 || sqlite3PagerIswriteable(pToRelease->pDbPage) );
|
|
|
|
/* If pPrior is part of the data area of pPage, then make sure pPage
|
|
** is still writeable */
|
|
assert( pPrior<pPage->aData || pPrior>=&pPage->aData[pBt->pageSize]
|
|
|| sqlite3PagerIswriteable(pPage->pDbPage) );
|
|
|
|
put4byte(pPrior, pgnoOvfl);
|
|
releasePage(pToRelease);
|
|
pToRelease = pOvfl;
|
|
pPrior = pOvfl->aData;
|
|
put4byte(pPrior, 0);
|
|
pPayload = &pOvfl->aData[4];
|
|
spaceLeft = pBt->usableSize - 4;
|
|
}
|
|
n = nPayload;
|
|
if( n>spaceLeft ) n = spaceLeft;
|
|
|
|
/* If pToRelease is not zero than pPayload points into the data area
|
|
** of pToRelease. Make sure pToRelease is still writeable. */
|
|
assert( pToRelease==0 || sqlite3PagerIswriteable(pToRelease->pDbPage) );
|
|
|
|
/* If pPayload is part of the data area of pPage, then make sure pPage
|
|
** is still writeable */
|
|
assert( pPayload<pPage->aData || pPayload>=&pPage->aData[pBt->pageSize]
|
|
|| sqlite3PagerIswriteable(pPage->pDbPage) );
|
|
|
|
if( nSrc>0 ){
|
|
if( n>nSrc ) n = nSrc;
|
|
assert( pSrc );
|
|
memcpy(pPayload, pSrc, n);
|
|
}else{
|
|
memset(pPayload, 0, n);
|
|
}
|
|
nPayload -= n;
|
|
pPayload += n;
|
|
pSrc += n;
|
|
nSrc -= n;
|
|
spaceLeft -= n;
|
|
if( nSrc==0 ){
|
|
nSrc = nData;
|
|
pSrc = pData;
|
|
}
|
|
}
|
|
releasePage(pToRelease);
|
|
return SQLITE_OK;
|
|
}
|
|
|
|
/*
|
|
** Remove the i-th cell from pPage. This routine effects pPage only.
|
|
** The cell content is not freed or deallocated. It is assumed that
|
|
** the cell content has been copied someplace else. This routine just
|
|
** removes the reference to the cell from pPage.
|
|
**
|
|
** "sz" must be the number of bytes in the cell.
|
|
*/
|
|
static void dropCell(MemPage *pPage, int idx, int sz, int *pRC){
|
|
int i; /* Loop counter */
|
|
u32 pc; /* Offset to cell content of cell being deleted */
|
|
u8 *data; /* pPage->aData */
|
|
u8 *ptr; /* Used to move bytes around within data[] */
|
|
int rc; /* The return code */
|
|
int hdr; /* Beginning of the header. 0 most pages. 100 page 1 */
|
|
|
|
if( *pRC ) return;
|
|
|
|
assert( idx>=0 && idx<pPage->nCell );
|
|
assert( sz==cellSize(pPage, idx) );
|
|
assert( sqlite3PagerIswriteable(pPage->pDbPage) );
|
|
assert( sqlite3_mutex_held(pPage->pBt->mutex) );
|
|
data = pPage->aData;
|
|
ptr = &data[pPage->cellOffset + 2*idx];
|
|
pc = get2byte(ptr);
|
|
hdr = pPage->hdrOffset;
|
|
testcase( pc==get2byte(&data[hdr+5]) );
|
|
testcase( pc+sz==pPage->pBt->usableSize );
|
|
if( pc < (u32)get2byte(&data[hdr+5]) || pc+sz > pPage->pBt->usableSize ){
|
|
*pRC = SQLITE_CORRUPT_BKPT;
|
|
return;
|
|
}
|
|
rc = freeSpace(pPage, pc, sz);
|
|
if( rc ){
|
|
*pRC = rc;
|
|
return;
|
|
}
|
|
for(i=idx+1; i<pPage->nCell; i++, ptr+=2){
|
|
ptr[0] = ptr[2];
|
|
ptr[1] = ptr[3];
|
|
}
|
|
pPage->nCell--;
|
|
put2byte(&data[hdr+3], pPage->nCell);
|
|
pPage->nFree += 2;
|
|
}
|
|
|
|
/*
|
|
** Insert a new cell on pPage at cell index "i". pCell points to the
|
|
** content of the cell.
|
|
**
|
|
** If the cell content will fit on the page, then put it there. If it
|
|
** will not fit, then make a copy of the cell content into pTemp if
|
|
** pTemp is not null. Regardless of pTemp, allocate a new entry
|
|
** in pPage->aOvfl[] and make it point to the cell content (either
|
|
** in pTemp or the original pCell) and also record its index.
|
|
** Allocating a new entry in pPage->aCell[] implies that
|
|
** pPage->nOverflow is incremented.
|
|
**
|
|
** If nSkip is non-zero, then do not copy the first nSkip bytes of the
|
|
** cell. The caller will overwrite them after this function returns. If
|
|
** nSkip is non-zero, then pCell may not point to an invalid memory location
|
|
** (but pCell+nSkip is always valid).
|
|
*/
|
|
static void insertCell(
|
|
MemPage *pPage, /* Page into which we are copying */
|
|
int i, /* New cell becomes the i-th cell of the page */
|
|
u8 *pCell, /* Content of the new cell */
|
|
int sz, /* Bytes of content in pCell */
|
|
u8 *pTemp, /* Temp storage space for pCell, if needed */
|
|
Pgno iChild, /* If non-zero, replace first 4 bytes with this value */
|
|
int *pRC /* Read and write return code from here */
|
|
){
|
|
int idx = 0; /* Where to write new cell content in data[] */
|
|
int j; /* Loop counter */
|
|
int end; /* First byte past the last cell pointer in data[] */
|
|
int ins; /* Index in data[] where new cell pointer is inserted */
|
|
int cellOffset; /* Address of first cell pointer in data[] */
|
|
u8 *data; /* The content of the whole page */
|
|
u8 *ptr; /* Used for moving information around in data[] */
|
|
|
|
int nSkip = (iChild ? 4 : 0);
|
|
|
|
if( *pRC ) return;
|
|
|
|
assert( i>=0 && i<=pPage->nCell+pPage->nOverflow );
|
|
assert( pPage->nCell<=MX_CELL(pPage->pBt) && MX_CELL(pPage->pBt)<=10921 );
|
|
assert( pPage->nOverflow<=ArraySize(pPage->aOvfl) );
|
|
assert( sqlite3_mutex_held(pPage->pBt->mutex) );
|
|
/* The cell should normally be sized correctly. However, when moving a
|
|
** malformed cell from a leaf page to an interior page, if the cell size
|
|
** wanted to be less than 4 but got rounded up to 4 on the leaf, then size
|
|
** might be less than 8 (leaf-size + pointer) on the interior node. Hence
|
|
** the term after the || in the following assert(). */
|
|
assert( sz==cellSizePtr(pPage, pCell) || (sz==8 && iChild>0) );
|
|
if( pPage->nOverflow || sz+2>pPage->nFree ){
|
|
if( pTemp ){
|
|
memcpy(pTemp+nSkip, pCell+nSkip, sz-nSkip);
|
|
pCell = pTemp;
|
|
}
|
|
if( iChild ){
|
|
put4byte(pCell, iChild);
|
|
}
|
|
j = pPage->nOverflow++;
|
|
assert( j<(int)(sizeof(pPage->aOvfl)/sizeof(pPage->aOvfl[0])) );
|
|
pPage->aOvfl[j].pCell = pCell;
|
|
pPage->aOvfl[j].idx = (u16)i;
|
|
}else{
|
|
int rc = sqlite3PagerWrite(pPage->pDbPage);
|
|
if( rc!=SQLITE_OK ){
|
|
*pRC = rc;
|
|
return;
|
|
}
|
|
assert( sqlite3PagerIswriteable(pPage->pDbPage) );
|
|
data = pPage->aData;
|
|
cellOffset = pPage->cellOffset;
|
|
end = cellOffset + 2*pPage->nCell;
|
|
ins = cellOffset + 2*i;
|
|
rc = allocateSpace(pPage, sz, &idx);
|
|
if( rc ){ *pRC = rc; return; }
|
|
/* The allocateSpace() routine guarantees the following two properties
|
|
** if it returns success */
|
|
assert( idx >= end+2 );
|
|
assert( idx+sz <= pPage->pBt->usableSize );
|
|
pPage->nCell++;
|
|
pPage->nFree -= (u16)(2 + sz);
|
|
memcpy(&data[idx+nSkip], pCell+nSkip, sz-nSkip);
|
|
if( iChild ){
|
|
put4byte(&data[idx], iChild);
|
|
}
|
|
for(j=end, ptr=&data[j]; j>ins; j-=2, ptr-=2){
|
|
ptr[0] = ptr[-2];
|
|
ptr[1] = ptr[-1];
|
|
}
|
|
put2byte(&data[ins], idx);
|
|
put2byte(&data[pPage->hdrOffset+3], pPage->nCell);
|
|
#ifndef SQLITE_OMIT_AUTOVACUUM
|
|
if( pPage->pBt->autoVacuum ){
|
|
/* The cell may contain a pointer to an overflow page. If so, write
|
|
** the entry for the overflow page into the pointer map.
|
|
*/
|
|
ptrmapPutOvflPtr(pPage, pCell, pRC);
|
|
}
|
|
#endif
|
|
}
|
|
}
|
|
|
|
/*
|
|
** Add a list of cells to a page. The page should be initially empty.
|
|
** The cells are guaranteed to fit on the page.
|
|
*/
|
|
static void assemblePage(
|
|
MemPage *pPage, /* The page to be assemblied */
|
|
int nCell, /* The number of cells to add to this page */
|
|
u8 **apCell, /* Pointers to cell bodies */
|
|
u16 *aSize /* Sizes of the cells */
|
|
){
|
|
int i; /* Loop counter */
|
|
u8 *pCellptr; /* Address of next cell pointer */
|
|
int cellbody; /* Address of next cell body */
|
|
u8 * const data = pPage->aData; /* Pointer to data for pPage */
|
|
const int hdr = pPage->hdrOffset; /* Offset of header on pPage */
|
|
const int nUsable = pPage->pBt->usableSize; /* Usable size of page */
|
|
|
|
assert( pPage->nOverflow==0 );
|
|
assert( sqlite3_mutex_held(pPage->pBt->mutex) );
|
|
assert( nCell>=0 && nCell<=MX_CELL(pPage->pBt) && MX_CELL(pPage->pBt)<=10921);
|
|
assert( sqlite3PagerIswriteable(pPage->pDbPage) );
|
|
|
|
/* Check that the page has just been zeroed by zeroPage() */
|
|
assert( pPage->nCell==0 );
|
|
assert( get2byteNotZero(&data[hdr+5])==nUsable );
|
|
|
|
pCellptr = &data[pPage->cellOffset + nCell*2];
|
|
cellbody = nUsable;
|
|
for(i=nCell-1; i>=0; i--){
|
|
pCellptr -= 2;
|
|
cellbody -= aSize[i];
|
|
put2byte(pCellptr, cellbody);
|
|
memcpy(&data[cellbody], apCell[i], aSize[i]);
|
|
}
|
|
put2byte(&data[hdr+3], nCell);
|
|
put2byte(&data[hdr+5], cellbody);
|
|
pPage->nFree -= (nCell*2 + nUsable - cellbody);
|
|
pPage->nCell = (u16)nCell;
|
|
}
|
|
|
|
/*
|
|
** The following parameters determine how many adjacent pages get involved
|
|
** in a balancing operation. NN is the number of neighbors on either side
|
|
** of the page that participate in the balancing operation. NB is the
|
|
** total number of pages that participate, including the target page and
|
|
** NN neighbors on either side.
|
|
**
|
|
** The minimum value of NN is 1 (of course). Increasing NN above 1
|
|
** (to 2 or 3) gives a modest improvement in SELECT and DELETE performance
|
|
** in exchange for a larger degradation in INSERT and UPDATE performance.
|
|
** The value of NN appears to give the best results overall.
|
|
*/
|
|
#define NN 1 /* Number of neighbors on either side of pPage */
|
|
#define NB (NN*2+1) /* Total pages involved in the balance */
|
|
|
|
|
|
#ifndef SQLITE_OMIT_QUICKBALANCE
|
|
/*
|
|
** This version of balance() handles the common special case where
|
|
** a new entry is being inserted on the extreme right-end of the
|
|
** tree, in other words, when the new entry will become the largest
|
|
** entry in the tree.
|
|
**
|
|
** Instead of trying to balance the 3 right-most leaf pages, just add
|
|
** a new page to the right-hand side and put the one new entry in
|
|
** that page. This leaves the right side of the tree somewhat
|
|
** unbalanced. But odds are that we will be inserting new entries
|
|
** at the end soon afterwards so the nearly empty page will quickly
|
|
** fill up. On average.
|
|
**
|
|
** pPage is the leaf page which is the right-most page in the tree.
|
|
** pParent is its parent. pPage must have a single overflow entry
|
|
** which is also the right-most entry on the page.
|
|
**
|
|
** The pSpace buffer is used to store a temporary copy of the divider
|
|
** cell that will be inserted into pParent. Such a cell consists of a 4
|
|
** byte page number followed by a variable length integer. In other
|
|
** words, at most 13 bytes. Hence the pSpace buffer must be at
|
|
** least 13 bytes in size.
|
|
*/
|
|
static int balance_quick(MemPage *pParent, MemPage *pPage, u8 *pSpace){
|
|
BtShared *const pBt = pPage->pBt; /* B-Tree Database */
|
|
MemPage *pNew; /* Newly allocated page */
|
|
int rc; /* Return Code */
|
|
Pgno pgnoNew; /* Page number of pNew */
|
|
|
|
assert( sqlite3_mutex_held(pPage->pBt->mutex) );
|
|
assert( sqlite3PagerIswriteable(pParent->pDbPage) );
|
|
assert( pPage->nOverflow==1 );
|
|
|
|
/* This error condition is now caught prior to reaching this function */
|
|
if( pPage->nCell<=0 ) return SQLITE_CORRUPT_BKPT;
|
|
|
|
/* Allocate a new page. This page will become the right-sibling of
|
|
** pPage. Make the parent page writable, so that the new divider cell
|
|
** may be inserted. If both these operations are successful, proceed.
|
|
*/
|
|
rc = allocateBtreePage(pBt, &pNew, &pgnoNew, 0, 0);
|
|
|
|
if( rc==SQLITE_OK ){
|
|
|
|
u8 *pOut = &pSpace[4];
|
|
u8 *pCell = pPage->aOvfl[0].pCell;
|
|
u16 szCell = cellSizePtr(pPage, pCell);
|
|
u8 *pStop;
|
|
|
|
assert( sqlite3PagerIswriteable(pNew->pDbPage) );
|
|
assert( pPage->aData[0]==(PTF_INTKEY|PTF_LEAFDATA|PTF_LEAF) );
|
|
zeroPage(pNew, PTF_INTKEY|PTF_LEAFDATA|PTF_LEAF);
|
|
assemblePage(pNew, 1, &pCell, &szCell);
|
|
|
|
/* If this is an auto-vacuum database, update the pointer map
|
|
** with entries for the new page, and any pointer from the
|
|
** cell on the page to an overflow page. If either of these
|
|
** operations fails, the return code is set, but the contents
|
|
** of the parent page are still manipulated by thh code below.
|
|
** That is Ok, at this point the parent page is guaranteed to
|
|
** be marked as dirty. Returning an error code will cause a
|
|
** rollback, undoing any changes made to the parent page.
|
|
*/
|
|
if( ISAUTOVACUUM ){
|
|
ptrmapPut(pBt, pgnoNew, PTRMAP_BTREE, pParent->pgno, &rc);
|
|
if( szCell>pNew->minLocal ){
|
|
ptrmapPutOvflPtr(pNew, pCell, &rc);
|
|
}
|
|
}
|
|
|
|
/* Create a divider cell to insert into pParent. The divider cell
|
|
** consists of a 4-byte page number (the page number of pPage) and
|
|
** a variable length key value (which must be the same value as the
|
|
** largest key on pPage).
|
|
**
|
|
** To find the largest key value on pPage, first find the right-most
|
|
** cell on pPage. The first two fields of this cell are the
|
|
** record-length (a variable length integer at most 32-bits in size)
|
|
** and the key value (a variable length integer, may have any value).
|
|
** The first of the while(...) loops below skips over the record-length
|
|
** field. The second while(...) loop copies the key value from the
|
|
** cell on pPage into the pSpace buffer.
|
|
*/
|
|
pCell = findCell(pPage, pPage->nCell-1);
|
|
pStop = &pCell[9];
|
|
while( (*(pCell++)&0x80) && pCell<pStop );
|
|
pStop = &pCell[9];
|
|
while( ((*(pOut++) = *(pCell++))&0x80) && pCell<pStop );
|
|
|
|
/* Insert the new divider cell into pParent. */
|
|
insertCell(pParent, pParent->nCell, pSpace, (int)(pOut-pSpace),
|
|
0, pPage->pgno, &rc);
|
|
|
|
/* Set the right-child pointer of pParent to point to the new page. */
|
|
put4byte(&pParent->aData[pParent->hdrOffset+8], pgnoNew);
|
|
|
|
/* Release the reference to the new page. */
|
|
releasePage(pNew);
|
|
}
|
|
|
|
return rc;
|
|
}
|
|
#endif /* SQLITE_OMIT_QUICKBALANCE */
|
|
|
|
#if 0
|
|
/*
|
|
** This function does not contribute anything to the operation of SQLite.
|
|
** it is sometimes activated temporarily while debugging code responsible
|
|
** for setting pointer-map entries.
|
|
*/
|
|
static int ptrmapCheckPages(MemPage **apPage, int nPage){
|
|
int i, j;
|
|
for(i=0; i<nPage; i++){
|
|
Pgno n;
|
|
u8 e;
|
|
MemPage *pPage = apPage[i];
|
|
BtShared *pBt = pPage->pBt;
|
|
assert( pPage->isInit );
|
|
|
|
for(j=0; j<pPage->nCell; j++){
|
|
CellInfo info;
|
|
u8 *z;
|
|
|
|
z = findCell(pPage, j);
|
|
btreeParseCellPtr(pPage, z, &info);
|
|
if( info.iOverflow ){
|
|
Pgno ovfl = get4byte(&z[info.iOverflow]);
|
|
ptrmapGet(pBt, ovfl, &e, &n);
|
|
assert( n==pPage->pgno && e==PTRMAP_OVERFLOW1 );
|
|
}
|
|
if( !pPage->leaf ){
|
|
Pgno child = get4byte(z);
|
|
ptrmapGet(pBt, child, &e, &n);
|
|
assert( n==pPage->pgno && e==PTRMAP_BTREE );
|
|
}
|
|
}
|
|
if( !pPage->leaf ){
|
|
Pgno child = get4byte(&pPage->aData[pPage->hdrOffset+8]);
|
|
ptrmapGet(pBt, child, &e, &n);
|
|
assert( n==pPage->pgno && e==PTRMAP_BTREE );
|
|
}
|
|
}
|
|
return 1;
|
|
}
|
|
#endif
|
|
|
|
/*
|
|
** This function is used to copy the contents of the b-tree node stored
|
|
** on page pFrom to page pTo. If page pFrom was not a leaf page, then
|
|
** the pointer-map entries for each child page are updated so that the
|
|
** parent page stored in the pointer map is page pTo. If pFrom contained
|
|
** any cells with overflow page pointers, then the corresponding pointer
|
|
** map entries are also updated so that the parent page is page pTo.
|
|
**
|
|
** If pFrom is currently carrying any overflow cells (entries in the
|
|
** MemPage.aOvfl[] array), they are not copied to pTo.
|
|
**
|
|
** Before returning, page pTo is reinitialized using btreeInitPage().
|
|
**
|
|
** The performance of this function is not critical. It is only used by
|
|
** the balance_shallower() and balance_deeper() procedures, neither of
|
|
** which are called often under normal circumstances.
|
|
*/
|
|
static void copyNodeContent(MemPage *pFrom, MemPage *pTo, int *pRC){
|
|
if( (*pRC)==SQLITE_OK ){
|
|
BtShared * const pBt = pFrom->pBt;
|
|
u8 * const aFrom = pFrom->aData;
|
|
u8 * const aTo = pTo->aData;
|
|
int const iFromHdr = pFrom->hdrOffset;
|
|
int const iToHdr = ((pTo->pgno==1) ? 100 : 0);
|
|
int rc;
|
|
int iData;
|
|
|
|
|
|
assert( pFrom->isInit );
|
|
assert( pFrom->nFree>=iToHdr );
|
|
assert( get2byte(&aFrom[iFromHdr+5])<=pBt->usableSize );
|
|
|
|
/* Copy the b-tree node content from page pFrom to page pTo. */
|
|
iData = get2byte(&aFrom[iFromHdr+5]);
|
|
memcpy(&aTo[iData], &aFrom[iData], pBt->usableSize-iData);
|
|
memcpy(&aTo[iToHdr], &aFrom[iFromHdr], pFrom->cellOffset + 2*pFrom->nCell);
|
|
|
|
/* Reinitialize page pTo so that the contents of the MemPage structure
|
|
** match the new data. The initialization of pTo can actually fail under
|
|
** fairly obscure circumstances, even though it is a copy of initialized
|
|
** page pFrom.
|
|
*/
|
|
pTo->isInit = 0;
|
|
rc = btreeInitPage(pTo);
|
|
if( rc!=SQLITE_OK ){
|
|
*pRC = rc;
|
|
return;
|
|
}
|
|
|
|
/* If this is an auto-vacuum database, update the pointer-map entries
|
|
** for any b-tree or overflow pages that pTo now contains the pointers to.
|
|
*/
|
|
if( ISAUTOVACUUM ){
|
|
*pRC = setChildPtrmaps(pTo);
|
|
}
|
|
}
|
|
}
|
|
|
|
/*
|
|
** This routine redistributes cells on the iParentIdx'th child of pParent
|
|
** (hereafter "the page") and up to 2 siblings so that all pages have about the
|
|
** same amount of free space. Usually a single sibling on either side of the
|
|
** page are used in the balancing, though both siblings might come from one
|
|
** side if the page is the first or last child of its parent. If the page
|
|
** has fewer than 2 siblings (something which can only happen if the page
|
|
** is a root page or a child of a root page) then all available siblings
|
|
** participate in the balancing.
|
|
**
|
|
** The number of siblings of the page might be increased or decreased by
|
|
** one or two in an effort to keep pages nearly full but not over full.
|
|
**
|
|
** Note that when this routine is called, some of the cells on the page
|
|
** might not actually be stored in MemPage.aData[]. This can happen
|
|
** if the page is overfull. This routine ensures that all cells allocated
|
|
** to the page and its siblings fit into MemPage.aData[] before returning.
|
|
**
|
|
** In the course of balancing the page and its siblings, cells may be
|
|
** inserted into or removed from the parent page (pParent). Doing so
|
|
** may cause the parent page to become overfull or underfull. If this
|
|
** happens, it is the responsibility of the caller to invoke the correct
|
|
** balancing routine to fix this problem (see the balance() routine).
|
|
**
|
|
** If this routine fails for any reason, it might leave the database
|
|
** in a corrupted state. So if this routine fails, the database should
|
|
** be rolled back.
|
|
**
|
|
** The third argument to this function, aOvflSpace, is a pointer to a
|
|
** buffer big enough to hold one page. If while inserting cells into the parent
|
|
** page (pParent) the parent page becomes overfull, this buffer is
|
|
** used to store the parent's overflow cells. Because this function inserts
|
|
** a maximum of four divider cells into the parent page, and the maximum
|
|
** size of a cell stored within an internal node is always less than 1/4
|
|
** of the page-size, the aOvflSpace[] buffer is guaranteed to be large
|
|
** enough for all overflow cells.
|
|
**
|
|
** If aOvflSpace is set to a null pointer, this function returns
|
|
** SQLITE_NOMEM.
|
|
*/
|
|
static int balance_nonroot(
|
|
MemPage *pParent, /* Parent page of siblings being balanced */
|
|
int iParentIdx, /* Index of "the page" in pParent */
|
|
u8 *aOvflSpace, /* page-size bytes of space for parent ovfl */
|
|
int isRoot /* True if pParent is a root-page */
|
|
){
|
|
BtShared *pBt; /* The whole database */
|
|
int nCell = 0; /* Number of cells in apCell[] */
|
|
int nMaxCells = 0; /* Allocated size of apCell, szCell, aFrom. */
|
|
int nNew = 0; /* Number of pages in apNew[] */
|
|
int nOld; /* Number of pages in apOld[] */
|
|
int i, j, k; /* Loop counters */
|
|
int nxDiv; /* Next divider slot in pParent->aCell[] */
|
|
int rc = SQLITE_OK; /* The return code */
|
|
u16 leafCorrection; /* 4 if pPage is a leaf. 0 if not */
|
|
int leafData; /* True if pPage is a leaf of a LEAFDATA tree */
|
|
int usableSpace; /* Bytes in pPage beyond the header */
|
|
int pageFlags; /* Value of pPage->aData[0] */
|
|
int subtotal; /* Subtotal of bytes in cells on one page */
|
|
int iSpace1 = 0; /* First unused byte of aSpace1[] */
|
|
int iOvflSpace = 0; /* First unused byte of aOvflSpace[] */
|
|
int szScratch; /* Size of scratch memory requested */
|
|
MemPage *apOld[NB]; /* pPage and up to two siblings */
|
|
MemPage *apCopy[NB]; /* Private copies of apOld[] pages */
|
|
MemPage *apNew[NB+2]; /* pPage and up to NB siblings after balancing */
|
|
u8 *pRight; /* Location in parent of right-sibling pointer */
|
|
u8 *apDiv[NB-1]; /* Divider cells in pParent */
|
|
int cntNew[NB+2]; /* Index in aCell[] of cell after i-th page */
|
|
int szNew[NB+2]; /* Combined size of cells place on i-th page */
|
|
u8 **apCell = 0; /* All cells begin balanced */
|
|
u16 *szCell; /* Local size of all cells in apCell[] */
|
|
u8 *aSpace1; /* Space for copies of dividers cells */
|
|
Pgno pgno; /* Temp var to store a page number in */
|
|
|
|
pBt = pParent->pBt;
|
|
assert( sqlite3_mutex_held(pBt->mutex) );
|
|
assert( sqlite3PagerIswriteable(pParent->pDbPage) );
|
|
|
|
#if 0
|
|
TRACE(("BALANCE: begin page %d child of %d\n", pPage->pgno, pParent->pgno));
|
|
#endif
|
|
|
|
/* At this point pParent may have at most one overflow cell. And if
|
|
** this overflow cell is present, it must be the cell with
|
|
** index iParentIdx. This scenario comes about when this function
|
|
** is called (indirectly) from sqlite3BtreeDelete().
|
|
*/
|
|
assert( pParent->nOverflow==0 || pParent->nOverflow==1 );
|
|
assert( pParent->nOverflow==0 || pParent->aOvfl[0].idx==iParentIdx );
|
|
|
|
if( !aOvflSpace ){
|
|
return SQLITE_NOMEM;
|
|
}
|
|
|
|
/* Find the sibling pages to balance. Also locate the cells in pParent
|
|
** that divide the siblings. An attempt is made to find NN siblings on
|
|
** either side of pPage. More siblings are taken from one side, however,
|
|
** if there are fewer than NN siblings on the other side. If pParent
|
|
** has NB or fewer children then all children of pParent are taken.
|
|
**
|
|
** This loop also drops the divider cells from the parent page. This
|
|
** way, the remainder of the function does not have to deal with any
|
|
** overflow cells in the parent page, since if any existed they will
|
|
** have already been removed.
|
|
*/
|
|
i = pParent->nOverflow + pParent->nCell;
|
|
if( i<2 ){
|
|
nxDiv = 0;
|
|
nOld = i+1;
|
|
}else{
|
|
nOld = 3;
|
|
if( iParentIdx==0 ){
|
|
nxDiv = 0;
|
|
}else if( iParentIdx==i ){
|
|
nxDiv = i-2;
|
|
}else{
|
|
nxDiv = iParentIdx-1;
|
|
}
|
|
i = 2;
|
|
}
|
|
if( (i+nxDiv-pParent->nOverflow)==pParent->nCell ){
|
|
pRight = &pParent->aData[pParent->hdrOffset+8];
|
|
}else{
|
|
pRight = findCell(pParent, i+nxDiv-pParent->nOverflow);
|
|
}
|
|
pgno = get4byte(pRight);
|
|
while( 1 ){
|
|
rc = getAndInitPage(pBt, pgno, &apOld[i]);
|
|
if( rc ){
|
|
memset(apOld, 0, (i+1)*sizeof(MemPage*));
|
|
goto balance_cleanup;
|
|
}
|
|
nMaxCells += 1+apOld[i]->nCell+apOld[i]->nOverflow;
|
|
if( (i--)==0 ) break;
|
|
|
|
if( i+nxDiv==pParent->aOvfl[0].idx && pParent->nOverflow ){
|
|
apDiv[i] = pParent->aOvfl[0].pCell;
|
|
pgno = get4byte(apDiv[i]);
|
|
szNew[i] = cellSizePtr(pParent, apDiv[i]);
|
|
pParent->nOverflow = 0;
|
|
}else{
|
|
apDiv[i] = findCell(pParent, i+nxDiv-pParent->nOverflow);
|
|
pgno = get4byte(apDiv[i]);
|
|
szNew[i] = cellSizePtr(pParent, apDiv[i]);
|
|
|
|
/* Drop the cell from the parent page. apDiv[i] still points to
|
|
** the cell within the parent, even though it has been dropped.
|
|
** This is safe because dropping a cell only overwrites the first
|
|
** four bytes of it, and this function does not need the first
|
|
** four bytes of the divider cell. So the pointer is safe to use
|
|
** later on.
|
|
**
|
|
** Unless SQLite is compiled in secure-delete mode. In this case,
|
|
** the dropCell() routine will overwrite the entire cell with zeroes.
|
|
** In this case, temporarily copy the cell into the aOvflSpace[]
|
|
** buffer. It will be copied out again as soon as the aSpace[] buffer
|
|
** is allocated. */
|
|
if( pBt->secureDelete ){
|
|
int iOff = SQLITE_PTR_TO_INT(apDiv[i]) - SQLITE_PTR_TO_INT(pParent->aData);
|
|
if( (iOff+szNew[i])>(int)pBt->usableSize ){
|
|
rc = SQLITE_CORRUPT_BKPT;
|
|
memset(apOld, 0, (i+1)*sizeof(MemPage*));
|
|
goto balance_cleanup;
|
|
}else{
|
|
memcpy(&aOvflSpace[iOff], apDiv[i], szNew[i]);
|
|
apDiv[i] = &aOvflSpace[apDiv[i]-pParent->aData];
|
|
}
|
|
}
|
|
dropCell(pParent, i+nxDiv-pParent->nOverflow, szNew[i], &rc);
|
|
}
|
|
}
|
|
|
|
/* Make nMaxCells a multiple of 4 in order to preserve 8-byte
|
|
** alignment */
|
|
nMaxCells = (nMaxCells + 3)&~3;
|
|
|
|
/*
|
|
** Allocate space for memory structures
|
|
*/
|
|
k = pBt->pageSize + ROUND8(sizeof(MemPage));
|
|
szScratch =
|
|
nMaxCells*sizeof(u8*) /* apCell */
|
|
+ nMaxCells*sizeof(u16) /* szCell */
|
|
+ pBt->pageSize /* aSpace1 */
|
|
+ k*nOld; /* Page copies (apCopy) */
|
|
apCell = sqlite3ScratchMalloc( szScratch );
|
|
if( apCell==0 ){
|
|
rc = SQLITE_NOMEM;
|
|
goto balance_cleanup;
|
|
}
|
|
szCell = (u16*)&apCell[nMaxCells];
|
|
aSpace1 = (u8*)&szCell[nMaxCells];
|
|
assert( EIGHT_BYTE_ALIGNMENT(aSpace1) );
|
|
|
|
/*
|
|
** Load pointers to all cells on sibling pages and the divider cells
|
|
** into the local apCell[] array. Make copies of the divider cells
|
|
** into space obtained from aSpace1[] and remove the the divider Cells
|
|
** from pParent.
|
|
**
|
|
** If the siblings are on leaf pages, then the child pointers of the
|
|
** divider cells are stripped from the cells before they are copied
|
|
** into aSpace1[]. In this way, all cells in apCell[] are without
|
|
** child pointers. If siblings are not leaves, then all cell in
|
|
** apCell[] include child pointers. Either way, all cells in apCell[]
|
|
** are alike.
|
|
**
|
|
** leafCorrection: 4 if pPage is a leaf. 0 if pPage is not a leaf.
|
|
** leafData: 1 if pPage holds key+data and pParent holds only keys.
|
|
*/
|
|
leafCorrection = apOld[0]->leaf*4;
|
|
leafData = apOld[0]->hasData;
|
|
for(i=0; i<nOld; i++){
|
|
int limit;
|
|
|
|
/* Before doing anything else, take a copy of the i'th original sibling
|
|
** The rest of this function will use data from the copies rather
|
|
** that the original pages since the original pages will be in the
|
|
** process of being overwritten. */
|
|
MemPage *pOld = apCopy[i] = (MemPage*)&aSpace1[pBt->pageSize + k*i];
|
|
memcpy(pOld, apOld[i], sizeof(MemPage));
|
|
pOld->aData = (void*)&pOld[1];
|
|
memcpy(pOld->aData, apOld[i]->aData, pBt->pageSize);
|
|
|
|
limit = pOld->nCell+pOld->nOverflow;
|
|
for(j=0; j<limit; j++){
|
|
assert( nCell<nMaxCells );
|
|
apCell[nCell] = findOverflowCell(pOld, j);
|
|
szCell[nCell] = cellSizePtr(pOld, apCell[nCell]);
|
|
nCell++;
|
|
}
|
|
if( i<nOld-1 && !leafData){
|
|
u16 sz = (u16)szNew[i];
|
|
u8 *pTemp;
|
|
assert( nCell<nMaxCells );
|
|
szCell[nCell] = sz;
|
|
pTemp = &aSpace1[iSpace1];
|
|
iSpace1 += sz;
|
|
assert( sz<=pBt->maxLocal+23 );
|
|
assert( iSpace1<=pBt->pageSize );
|
|
memcpy(pTemp, apDiv[i], sz);
|
|
apCell[nCell] = pTemp+leafCorrection;
|
|
assert( leafCorrection==0 || leafCorrection==4 );
|
|
szCell[nCell] = szCell[nCell] - leafCorrection;
|
|
if( !pOld->leaf ){
|
|
assert( leafCorrection==0 );
|
|
assert( pOld->hdrOffset==0 );
|
|
/* The right pointer of the child page pOld becomes the left
|
|
** pointer of the divider cell */
|
|
memcpy(apCell[nCell], &pOld->aData[8], 4);
|
|
}else{
|
|
assert( leafCorrection==4 );
|
|
if( szCell[nCell]<4 ){
|
|
/* Do not allow any cells smaller than 4 bytes. */
|
|
szCell[nCell] = 4;
|
|
}
|
|
}
|
|
nCell++;
|
|
}
|
|
}
|
|
|
|
/*
|
|
** Figure out the number of pages needed to hold all nCell cells.
|
|
** Store this number in "k". Also compute szNew[] which is the total
|
|
** size of all cells on the i-th page and cntNew[] which is the index
|
|
** in apCell[] of the cell that divides page i from page i+1.
|
|
** cntNew[k] should equal nCell.
|
|
**
|
|
** Values computed by this block:
|
|
**
|
|
** k: The total number of sibling pages
|
|
** szNew[i]: Spaced used on the i-th sibling page.
|
|
** cntNew[i]: Index in apCell[] and szCell[] for the first cell to
|
|
** the right of the i-th sibling page.
|
|
** usableSpace: Number of bytes of space available on each sibling.
|
|
**
|
|
*/
|
|
usableSpace = pBt->usableSize - 12 + leafCorrection;
|
|
for(subtotal=k=i=0; i<nCell; i++){
|
|
assert( i<nMaxCells );
|
|
subtotal += szCell[i] + 2;
|
|
if( subtotal > usableSpace ){
|
|
szNew[k] = subtotal - szCell[i];
|
|
cntNew[k] = i;
|
|
if( leafData ){ i--; }
|
|
subtotal = 0;
|
|
k++;
|
|
if( k>NB+1 ){ rc = SQLITE_CORRUPT_BKPT; goto balance_cleanup; }
|
|
}
|
|
}
|
|
szNew[k] = subtotal;
|
|
cntNew[k] = nCell;
|
|
k++;
|
|
|
|
/*
|
|
** The packing computed by the previous block is biased toward the siblings
|
|
** on the left side. The left siblings are always nearly full, while the
|
|
** right-most sibling might be nearly empty. This block of code attempts
|
|
** to adjust the packing of siblings to get a better balance.
|
|
**
|
|
** This adjustment is more than an optimization. The packing above might
|
|
** be so out of balance as to be illegal. For example, the right-most
|
|
** sibling might be completely empty. This adjustment is not optional.
|
|
*/
|
|
for(i=k-1; i>0; i--){
|
|
int szRight = szNew[i]; /* Size of sibling on the right */
|
|
int szLeft = szNew[i-1]; /* Size of sibling on the left */
|
|
int r; /* Index of right-most cell in left sibling */
|
|
int d; /* Index of first cell to the left of right sibling */
|
|
|
|
r = cntNew[i-1] - 1;
|
|
d = r + 1 - leafData;
|
|
assert( d<nMaxCells );
|
|
assert( r<nMaxCells );
|
|
while( szRight==0 || szRight+szCell[d]+2<=szLeft-(szCell[r]+2) ){
|
|
szRight += szCell[d] + 2;
|
|
szLeft -= szCell[r] + 2;
|
|
cntNew[i-1]--;
|
|
r = cntNew[i-1] - 1;
|
|
d = r + 1 - leafData;
|
|
}
|
|
szNew[i] = szRight;
|
|
szNew[i-1] = szLeft;
|
|
}
|
|
|
|
/* Either we found one or more cells (cntnew[0])>0) or pPage is
|
|
** a virtual root page. A virtual root page is when the real root
|
|
** page is page 1 and we are the only child of that page.
|
|
*/
|
|
assert( cntNew[0]>0 || (pParent->pgno==1 && pParent->nCell==0) );
|
|
|
|
TRACE(("BALANCE: old: %d %d %d ",
|
|
apOld[0]->pgno,
|
|
nOld>=2 ? apOld[1]->pgno : 0,
|
|
nOld>=3 ? apOld[2]->pgno : 0
|
|
));
|
|
|
|
/*
|
|
** Allocate k new pages. Reuse old pages where possible.
|
|
*/
|
|
if( apOld[0]->pgno<=1 ){
|
|
rc = SQLITE_CORRUPT_BKPT;
|
|
goto balance_cleanup;
|
|
}
|
|
pageFlags = apOld[0]->aData[0];
|
|
for(i=0; i<k; i++){
|
|
MemPage *pNew;
|
|
if( i<nOld ){
|
|
pNew = apNew[i] = apOld[i];
|
|
apOld[i] = 0;
|
|
rc = sqlite3PagerWrite(pNew->pDbPage);
|
|
nNew++;
|
|
if( rc ) goto balance_cleanup;
|
|
}else{
|
|
assert( i>0 );
|
|
rc = allocateBtreePage(pBt, &pNew, &pgno, pgno, 0);
|
|
if( rc ) goto balance_cleanup;
|
|
apNew[i] = pNew;
|
|
nNew++;
|
|
|
|
/* Set the pointer-map entry for the new sibling page. */
|
|
if( ISAUTOVACUUM ){
|
|
ptrmapPut(pBt, pNew->pgno, PTRMAP_BTREE, pParent->pgno, &rc);
|
|
if( rc!=SQLITE_OK ){
|
|
goto balance_cleanup;
|
|
}
|
|
}
|
|
}
|
|
}
|
|
|
|
/* Free any old pages that were not reused as new pages.
|
|
*/
|
|
while( i<nOld ){
|
|
freePage(apOld[i], &rc);
|
|
if( rc ) goto balance_cleanup;
|
|
releasePage(apOld[i]);
|
|
apOld[i] = 0;
|
|
i++;
|
|
}
|
|
|
|
/*
|
|
** Put the new pages in accending order. This helps to
|
|
** keep entries in the disk file in order so that a scan
|
|
** of the table is a linear scan through the file. That
|
|
** in turn helps the operating system to deliver pages
|
|
** from the disk more rapidly.
|
|
**
|
|
** An O(n^2) insertion sort algorithm is used, but since
|
|
** n is never more than NB (a small constant), that should
|
|
** not be a problem.
|
|
**
|
|
** When NB==3, this one optimization makes the database
|
|
** about 25% faster for large insertions and deletions.
|
|
*/
|
|
for(i=0; i<k-1; i++){
|
|
int minV = apNew[i]->pgno;
|
|
int minI = i;
|
|
for(j=i+1; j<k; j++){
|
|
if( apNew[j]->pgno<(unsigned)minV ){
|
|
minI = j;
|
|
minV = apNew[j]->pgno;
|
|
}
|
|
}
|
|
if( minI>i ){
|
|
MemPage *pT;
|
|
pT = apNew[i];
|
|
apNew[i] = apNew[minI];
|
|
apNew[minI] = pT;
|
|
}
|
|
}
|
|
TRACE(("new: %d(%d) %d(%d) %d(%d) %d(%d) %d(%d)\n",
|
|
apNew[0]->pgno, szNew[0],
|
|
nNew>=2 ? apNew[1]->pgno : 0, nNew>=2 ? szNew[1] : 0,
|
|
nNew>=3 ? apNew[2]->pgno : 0, nNew>=3 ? szNew[2] : 0,
|
|
nNew>=4 ? apNew[3]->pgno : 0, nNew>=4 ? szNew[3] : 0,
|
|
nNew>=5 ? apNew[4]->pgno : 0, nNew>=5 ? szNew[4] : 0));
|
|
|
|
assert( sqlite3PagerIswriteable(pParent->pDbPage) );
|
|
put4byte(pRight, apNew[nNew-1]->pgno);
|
|
|
|
/*
|
|
** Evenly distribute the data in apCell[] across the new pages.
|
|
** Insert divider cells into pParent as necessary.
|
|
*/
|
|
j = 0;
|
|
for(i=0; i<nNew; i++){
|
|
/* Assemble the new sibling page. */
|
|
MemPage *pNew = apNew[i];
|
|
assert( j<nMaxCells );
|
|
zeroPage(pNew, pageFlags);
|
|
assemblePage(pNew, cntNew[i]-j, &apCell[j], &szCell[j]);
|
|
assert( pNew->nCell>0 || (nNew==1 && cntNew[0]==0) );
|
|
assert( pNew->nOverflow==0 );
|
|
|
|
j = cntNew[i];
|
|
|
|
/* If the sibling page assembled above was not the right-most sibling,
|
|
** insert a divider cell into the parent page.
|
|
*/
|
|
assert( i<nNew-1 || j==nCell );
|
|
if( j<nCell ){
|
|
u8 *pCell;
|
|
u8 *pTemp;
|
|
int sz;
|
|
|
|
assert( j<nMaxCells );
|
|
pCell = apCell[j];
|
|
sz = szCell[j] + leafCorrection;
|
|
pTemp = &aOvflSpace[iOvflSpace];
|
|
if( !pNew->leaf ){
|
|
memcpy(&pNew->aData[8], pCell, 4);
|
|
}else if( leafData ){
|
|
/* If the tree is a leaf-data tree, and the siblings are leaves,
|
|
** then there is no divider cell in apCell[]. Instead, the divider
|
|
** cell consists of the integer key for the right-most cell of
|
|
** the sibling-page assembled above only.
|
|
*/
|
|
CellInfo info;
|
|
j--;
|
|
btreeParseCellPtr(pNew, apCell[j], &info);
|
|
pCell = pTemp;
|
|
sz = 4 + putVarint(&pCell[4], info.nKey);
|
|
pTemp = 0;
|
|
}else{
|
|
pCell -= 4;
|
|
/* Obscure case for non-leaf-data trees: If the cell at pCell was
|
|
** previously stored on a leaf node, and its reported size was 4
|
|
** bytes, then it may actually be smaller than this
|
|
** (see btreeParseCellPtr(), 4 bytes is the minimum size of
|
|
** any cell). But it is important to pass the correct size to
|
|
** insertCell(), so reparse the cell now.
|
|
**
|
|
** Note that this can never happen in an SQLite data file, as all
|
|
** cells are at least 4 bytes. It only happens in b-trees used
|
|
** to evaluate "IN (SELECT ...)" and similar clauses.
|
|
*/
|
|
if( szCell[j]==4 ){
|
|
assert(leafCorrection==4);
|
|
sz = cellSizePtr(pParent, pCell);
|
|
}
|
|
}
|
|
iOvflSpace += sz;
|
|
assert( sz<=pBt->maxLocal+23 );
|
|
assert( iOvflSpace<=pBt->pageSize );
|
|
insertCell(pParent, nxDiv, pCell, sz, pTemp, pNew->pgno, &rc);
|
|
if( rc!=SQLITE_OK ) goto balance_cleanup;
|
|
assert( sqlite3PagerIswriteable(pParent->pDbPage) );
|
|
|
|
j++;
|
|
nxDiv++;
|
|
}
|
|
}
|
|
assert( j==nCell );
|
|
assert( nOld>0 );
|
|
assert( nNew>0 );
|
|
if( (pageFlags & PTF_LEAF)==0 ){
|
|
u8 *zChild = &apCopy[nOld-1]->aData[8];
|
|
memcpy(&apNew[nNew-1]->aData[8], zChild, 4);
|
|
}
|
|
|
|
if( isRoot && pParent->nCell==0 && pParent->hdrOffset<=apNew[0]->nFree ){
|
|
/* The root page of the b-tree now contains no cells. The only sibling
|
|
** page is the right-child of the parent. Copy the contents of the
|
|
** child page into the parent, decreasing the overall height of the
|
|
** b-tree structure by one. This is described as the "balance-shallower"
|
|
** sub-algorithm in some documentation.
|
|
**
|
|
** If this is an auto-vacuum database, the call to copyNodeContent()
|
|
** sets all pointer-map entries corresponding to database image pages
|
|
** for which the pointer is stored within the content being copied.
|
|
**
|
|
** The second assert below verifies that the child page is defragmented
|
|
** (it must be, as it was just reconstructed using assemblePage()). This
|
|
** is important if the parent page happens to be page 1 of the database
|
|
** image. */
|
|
assert( nNew==1 );
|
|
assert( apNew[0]->nFree ==
|
|
(get2byte(&apNew[0]->aData[5])-apNew[0]->cellOffset-apNew[0]->nCell*2)
|
|
);
|
|
copyNodeContent(apNew[0], pParent, &rc);
|
|
freePage(apNew[0], &rc);
|
|
}else if( ISAUTOVACUUM ){
|
|
/* Fix the pointer-map entries for all the cells that were shifted around.
|
|
** There are several different types of pointer-map entries that need to
|
|
** be dealt with by this routine. Some of these have been set already, but
|
|
** many have not. The following is a summary:
|
|
**
|
|
** 1) The entries associated with new sibling pages that were not
|
|
** siblings when this function was called. These have already
|
|
** been set. We don't need to worry about old siblings that were
|
|
** moved to the free-list - the freePage() code has taken care
|
|
** of those.
|
|
**
|
|
** 2) The pointer-map entries associated with the first overflow
|
|
** page in any overflow chains used by new divider cells. These
|
|
** have also already been taken care of by the insertCell() code.
|
|
**
|
|
** 3) If the sibling pages are not leaves, then the child pages of
|
|
** cells stored on the sibling pages may need to be updated.
|
|
**
|
|
** 4) If the sibling pages are not internal intkey nodes, then any
|
|
** overflow pages used by these cells may need to be updated
|
|
** (internal intkey nodes never contain pointers to overflow pages).
|
|
**
|
|
** 5) If the sibling pages are not leaves, then the pointer-map
|
|
** entries for the right-child pages of each sibling may need
|
|
** to be updated.
|
|
**
|
|
** Cases 1 and 2 are dealt with above by other code. The next
|
|
** block deals with cases 3 and 4 and the one after that, case 5. Since
|
|
** setting a pointer map entry is a relatively expensive operation, this
|
|
** code only sets pointer map entries for child or overflow pages that have
|
|
** actually moved between pages. */
|
|
MemPage *pNew = apNew[0];
|
|
MemPage *pOld = apCopy[0];
|
|
int nOverflow = pOld->nOverflow;
|
|
int iNextOld = pOld->nCell + nOverflow;
|
|
int iOverflow = (nOverflow ? pOld->aOvfl[0].idx : -1);
|
|
j = 0; /* Current 'old' sibling page */
|
|
k = 0; /* Current 'new' sibling page */
|
|
for(i=0; i<nCell; i++){
|
|
int isDivider = 0;
|
|
while( i==iNextOld ){
|
|
/* Cell i is the cell immediately following the last cell on old
|
|
** sibling page j. If the siblings are not leaf pages of an
|
|
** intkey b-tree, then cell i was a divider cell. */
|
|
pOld = apCopy[++j];
|
|
iNextOld = i + !leafData + pOld->nCell + pOld->nOverflow;
|
|
if( pOld->nOverflow ){
|
|
nOverflow = pOld->nOverflow;
|
|
iOverflow = i + !leafData + pOld->aOvfl[0].idx;
|
|
}
|
|
isDivider = !leafData;
|
|
}
|
|
|
|
assert(nOverflow>0 || iOverflow<i );
|
|
assert(nOverflow<2 || pOld->aOvfl[0].idx==pOld->aOvfl[1].idx-1);
|
|
assert(nOverflow<3 || pOld->aOvfl[1].idx==pOld->aOvfl[2].idx-1);
|
|
if( i==iOverflow ){
|
|
isDivider = 1;
|
|
if( (--nOverflow)>0 ){
|
|
iOverflow++;
|
|
}
|
|
}
|
|
|
|
if( i==cntNew[k] ){
|
|
/* Cell i is the cell immediately following the last cell on new
|
|
** sibling page k. If the siblings are not leaf pages of an
|
|
** intkey b-tree, then cell i is a divider cell. */
|
|
pNew = apNew[++k];
|
|
if( !leafData ) continue;
|
|
}
|
|
assert( j<nOld );
|
|
assert( k<nNew );
|
|
|
|
/* If the cell was originally divider cell (and is not now) or
|
|
** an overflow cell, or if the cell was located on a different sibling
|
|
** page before the balancing, then the pointer map entries associated
|
|
** with any child or overflow pages need to be updated. */
|
|
if( isDivider || pOld->pgno!=pNew->pgno ){
|
|
if( !leafCorrection ){
|
|
ptrmapPut(pBt, get4byte(apCell[i]), PTRMAP_BTREE, pNew->pgno, &rc);
|
|
}
|
|
if( szCell[i]>pNew->minLocal ){
|
|
ptrmapPutOvflPtr(pNew, apCell[i], &rc);
|
|
}
|
|
}
|
|
}
|
|
|
|
if( !leafCorrection ){
|
|
for(i=0; i<nNew; i++){
|
|
u32 key = get4byte(&apNew[i]->aData[8]);
|
|
ptrmapPut(pBt, key, PTRMAP_BTREE, apNew[i]->pgno, &rc);
|
|
}
|
|
}
|
|
|
|
#if 0
|
|
/* The ptrmapCheckPages() contains assert() statements that verify that
|
|
** all pointer map pages are set correctly. This is helpful while
|
|
** debugging. This is usually disabled because a corrupt database may
|
|
** cause an assert() statement to fail. */
|
|
ptrmapCheckPages(apNew, nNew);
|
|
ptrmapCheckPages(&pParent, 1);
|
|
#endif
|
|
}
|
|
|
|
assert( pParent->isInit );
|
|
TRACE(("BALANCE: finished: old=%d new=%d cells=%d\n",
|
|
nOld, nNew, nCell));
|
|
|
|
/*
|
|
** Cleanup before returning.
|
|
*/
|
|
balance_cleanup:
|
|
sqlite3ScratchFree(apCell);
|
|
for(i=0; i<nOld; i++){
|
|
releasePage(apOld[i]);
|
|
}
|
|
for(i=0; i<nNew; i++){
|
|
releasePage(apNew[i]);
|
|
}
|
|
|
|
return rc;
|
|
}
|
|
|
|
|
|
/*
|
|
** This function is called when the root page of a b-tree structure is
|
|
** overfull (has one or more overflow pages).
|
|
**
|
|
** A new child page is allocated and the contents of the current root
|
|
** page, including overflow cells, are copied into the child. The root
|
|
** page is then overwritten to make it an empty page with the right-child
|
|
** pointer pointing to the new page.
|
|
**
|
|
** Before returning, all pointer-map entries corresponding to pages
|
|
** that the new child-page now contains pointers to are updated. The
|
|
** entry corresponding to the new right-child pointer of the root
|
|
** page is also updated.
|
|
**
|
|
** If successful, *ppChild is set to contain a reference to the child
|
|
** page and SQLITE_OK is returned. In this case the caller is required
|
|
** to call releasePage() on *ppChild exactly once. If an error occurs,
|
|
** an error code is returned and *ppChild is set to 0.
|
|
*/
|
|
static int balance_deeper(MemPage *pRoot, MemPage **ppChild){
|
|
int rc; /* Return value from subprocedures */
|
|
MemPage *pChild = 0; /* Pointer to a new child page */
|
|
Pgno pgnoChild = 0; /* Page number of the new child page */
|
|
BtShared *pBt = pRoot->pBt; /* The BTree */
|
|
|
|
assert( pRoot->nOverflow>0 );
|
|
assert( sqlite3_mutex_held(pBt->mutex) );
|
|
|
|
/* Make pRoot, the root page of the b-tree, writable. Allocate a new
|
|
** page that will become the new right-child of pPage. Copy the contents
|
|
** of the node stored on pRoot into the new child page.
|
|
*/
|
|
rc = sqlite3PagerWrite(pRoot->pDbPage);
|
|
if( rc==SQLITE_OK ){
|
|
rc = allocateBtreePage(pBt,&pChild,&pgnoChild,pRoot->pgno,0);
|
|
copyNodeContent(pRoot, pChild, &rc);
|
|
if( ISAUTOVACUUM ){
|
|
ptrmapPut(pBt, pgnoChild, PTRMAP_BTREE, pRoot->pgno, &rc);
|
|
}
|
|
}
|
|
if( rc ){
|
|
*ppChild = 0;
|
|
releasePage(pChild);
|
|
return rc;
|
|
}
|
|
assert( sqlite3PagerIswriteable(pChild->pDbPage) );
|
|
assert( sqlite3PagerIswriteable(pRoot->pDbPage) );
|
|
assert( pChild->nCell==pRoot->nCell );
|
|
|
|
TRACE(("BALANCE: copy root %d into %d\n", pRoot->pgno, pChild->pgno));
|
|
|
|
/* Copy the overflow cells from pRoot to pChild */
|
|
memcpy(pChild->aOvfl, pRoot->aOvfl, pRoot->nOverflow*sizeof(pRoot->aOvfl[0]));
|
|
pChild->nOverflow = pRoot->nOverflow;
|
|
|
|
/* Zero the contents of pRoot. Then install pChild as the right-child. */
|
|
zeroPage(pRoot, pChild->aData[0] & ~PTF_LEAF);
|
|
put4byte(&pRoot->aData[pRoot->hdrOffset+8], pgnoChild);
|
|
|
|
*ppChild = pChild;
|
|
return SQLITE_OK;
|
|
}
|
|
|
|
/*
|
|
** The page that pCur currently points to has just been modified in
|
|
** some way. This function figures out if this modification means the
|
|
** tree needs to be balanced, and if so calls the appropriate balancing
|
|
** routine. Balancing routines are:
|
|
**
|
|
** balance_quick()
|
|
** balance_deeper()
|
|
** balance_nonroot()
|
|
*/
|
|
static int balance(BtCursor *pCur){
|
|
int rc = SQLITE_OK;
|
|
const int nMin = pCur->pBt->usableSize * 2 / 3;
|
|
u8 aBalanceQuickSpace[13];
|
|
u8 *pFree = 0;
|
|
|
|
TESTONLY( int balance_quick_called = 0 );
|
|
TESTONLY( int balance_deeper_called = 0 );
|
|
|
|
do {
|
|
int iPage = pCur->iPage;
|
|
MemPage *pPage = pCur->apPage[iPage];
|
|
|
|
if( iPage==0 ){
|
|
if( pPage->nOverflow ){
|
|
/* The root page of the b-tree is overfull. In this case call the
|
|
** balance_deeper() function to create a new child for the root-page
|
|
** and copy the current contents of the root-page to it. The
|
|
** next iteration of the do-loop will balance the child page.
|
|
*/
|
|
assert( (balance_deeper_called++)==0 );
|
|
rc = balance_deeper(pPage, &pCur->apPage[1]);
|
|
if( rc==SQLITE_OK ){
|
|
pCur->iPage = 1;
|
|
pCur->aiIdx[0] = 0;
|
|
pCur->aiIdx[1] = 0;
|
|
assert( pCur->apPage[1]->nOverflow );
|
|
}
|
|
}else{
|
|
break;
|
|
}
|
|
}else if( pPage->nOverflow==0 && pPage->nFree<=nMin ){
|
|
break;
|
|
}else{
|
|
MemPage * const pParent = pCur->apPage[iPage-1];
|
|
int const iIdx = pCur->aiIdx[iPage-1];
|
|
|
|
rc = sqlite3PagerWrite(pParent->pDbPage);
|
|
if( rc==SQLITE_OK ){
|
|
#ifndef SQLITE_OMIT_QUICKBALANCE
|
|
if( pPage->hasData
|
|
&& pPage->nOverflow==1
|
|
&& pPage->aOvfl[0].idx==pPage->nCell
|
|
&& pParent->pgno!=1
|
|
&& pParent->nCell==iIdx
|
|
){
|
|
/* Call balance_quick() to create a new sibling of pPage on which
|
|
** to store the overflow cell. balance_quick() inserts a new cell
|
|
** into pParent, which may cause pParent overflow. If this
|
|
** happens, the next interation of the do-loop will balance pParent
|
|
** use either balance_nonroot() or balance_deeper(). Until this
|
|
** happens, the overflow cell is stored in the aBalanceQuickSpace[]
|
|
** buffer.
|
|
**
|
|
** The purpose of the following assert() is to check that only a
|
|
** single call to balance_quick() is made for each call to this
|
|
** function. If this were not verified, a subtle bug involving reuse
|
|
** of the aBalanceQuickSpace[] might sneak in.
|
|
*/
|
|
assert( (balance_quick_called++)==0 );
|
|
rc = balance_quick(pParent, pPage, aBalanceQuickSpace);
|
|
}else
|
|
#endif
|
|
{
|
|
/* In this case, call balance_nonroot() to redistribute cells
|
|
** between pPage and up to 2 of its sibling pages. This involves
|
|
** modifying the contents of pParent, which may cause pParent to
|
|
** become overfull or underfull. The next iteration of the do-loop
|
|
** will balance the parent page to correct this.
|
|
**
|
|
** If the parent page becomes overfull, the overflow cell or cells
|
|
** are stored in the pSpace buffer allocated immediately below.
|
|
** A subsequent iteration of the do-loop will deal with this by
|
|
** calling balance_nonroot() (balance_deeper() may be called first,
|
|
** but it doesn't deal with overflow cells - just moves them to a
|
|
** different page). Once this subsequent call to balance_nonroot()
|
|
** has completed, it is safe to release the pSpace buffer used by
|
|
** the previous call, as the overflow cell data will have been
|
|
** copied either into the body of a database page or into the new
|
|
** pSpace buffer passed to the latter call to balance_nonroot().
|
|
*/
|
|
u8 *pSpace = sqlite3PageMalloc(pCur->pBt->pageSize);
|
|
rc = balance_nonroot(pParent, iIdx, pSpace, iPage==1);
|
|
if( pFree ){
|
|
/* If pFree is not NULL, it points to the pSpace buffer used
|
|
** by a previous call to balance_nonroot(). Its contents are
|
|
** now stored either on real database pages or within the
|
|
** new pSpace buffer, so it may be safely freed here. */
|
|
sqlite3PageFree(pFree);
|
|
}
|
|
|
|
/* The pSpace buffer will be freed after the next call to
|
|
** balance_nonroot(), or just before this function returns, whichever
|
|
** comes first. */
|
|
pFree = pSpace;
|
|
}
|
|
}
|
|
|
|
pPage->nOverflow = 0;
|
|
|
|
/* The next iteration of the do-loop balances the parent page. */
|
|
releasePage(pPage);
|
|
pCur->iPage--;
|
|
}
|
|
}while( rc==SQLITE_OK );
|
|
|
|
if( pFree ){
|
|
sqlite3PageFree(pFree);
|
|
}
|
|
return rc;
|
|
}
|
|
|
|
|
|
/*
|
|
** Insert a new record into the BTree. The key is given by (pKey,nKey)
|
|
** and the data is given by (pData,nData). The cursor is used only to
|
|
** define what table the record should be inserted into. The cursor
|
|
** is left pointing at a random location.
|
|
**
|
|
** For an INTKEY table, only the nKey value of the key is used. pKey is
|
|
** ignored. For a ZERODATA table, the pData and nData are both ignored.
|
|
**
|
|
** If the seekResult parameter is non-zero, then a successful call to
|
|
** MovetoUnpacked() to seek cursor pCur to (pKey, nKey) has already
|
|
** been performed. seekResult is the search result returned (a negative
|
|
** number if pCur points at an entry that is smaller than (pKey, nKey), or
|
|
** a positive value if pCur points at an etry that is larger than
|
|
** (pKey, nKey)).
|
|
**
|
|
** If the seekResult parameter is non-zero, then the caller guarantees that
|
|
** cursor pCur is pointing at the existing copy of a row that is to be
|
|
** overwritten. If the seekResult parameter is 0, then cursor pCur may
|
|
** point to any entry or to no entry at all and so this function has to seek
|
|
** the cursor before the new key can be inserted.
|
|
*/
|
|
SQLITE_PRIVATE int sqlite3BtreeInsert(
|
|
BtCursor *pCur, /* Insert data into the table of this cursor */
|
|
const void *pKey, i64 nKey, /* The key of the new record */
|
|
const void *pData, int nData, /* The data of the new record */
|
|
int nZero, /* Number of extra 0 bytes to append to data */
|
|
int appendBias, /* True if this is likely an append */
|
|
int seekResult /* Result of prior MovetoUnpacked() call */
|
|
){
|
|
int rc;
|
|
int loc = seekResult; /* -1: before desired location +1: after */
|
|
int szNew = 0;
|
|
int idx;
|
|
MemPage *pPage;
|
|
Btree *p = pCur->pBtree;
|
|
BtShared *pBt = p->pBt;
|
|
unsigned char *oldCell;
|
|
unsigned char *newCell = 0;
|
|
|
|
if( pCur->eState==CURSOR_FAULT ){
|
|
assert( pCur->skipNext!=SQLITE_OK );
|
|
return pCur->skipNext;
|
|
}
|
|
|
|
assert( cursorHoldsMutex(pCur) );
|
|
assert( pCur->wrFlag && pBt->inTransaction==TRANS_WRITE && !pBt->readOnly );
|
|
assert( hasSharedCacheTableLock(p, pCur->pgnoRoot, pCur->pKeyInfo!=0, 2) );
|
|
|
|
/* Assert that the caller has been consistent. If this cursor was opened
|
|
** expecting an index b-tree, then the caller should be inserting blob
|
|
** keys with no associated data. If the cursor was opened expecting an
|
|
** intkey table, the caller should be inserting integer keys with a
|
|
** blob of associated data. */
|
|
assert( (pKey==0)==(pCur->pKeyInfo==0) );
|
|
|
|
/* If this is an insert into a table b-tree, invalidate any incrblob
|
|
** cursors open on the row being replaced (assuming this is a replace
|
|
** operation - if it is not, the following is a no-op). */
|
|
if( pCur->pKeyInfo==0 ){
|
|
invalidateIncrblobCursors(p, nKey, 0);
|
|
}
|
|
|
|
/* Save the positions of any other cursors open on this table.
|
|
**
|
|
** In some cases, the call to btreeMoveto() below is a no-op. For
|
|
** example, when inserting data into a table with auto-generated integer
|
|
** keys, the VDBE layer invokes sqlite3BtreeLast() to figure out the
|
|
** integer key to use. It then calls this function to actually insert the
|
|
** data into the intkey B-Tree. In this case btreeMoveto() recognizes
|
|
** that the cursor is already where it needs to be and returns without
|
|
** doing any work. To avoid thwarting these optimizations, it is important
|
|
** not to clear the cursor here.
|
|
*/
|
|
rc = saveAllCursors(pBt, pCur->pgnoRoot, pCur);
|
|
if( rc ) return rc;
|
|
if( !loc ){
|
|
rc = btreeMoveto(pCur, pKey, nKey, appendBias, &loc);
|
|
if( rc ) return rc;
|
|
}
|
|
assert( pCur->eState==CURSOR_VALID || (pCur->eState==CURSOR_INVALID && loc) );
|
|
|
|
pPage = pCur->apPage[pCur->iPage];
|
|
assert( pPage->intKey || nKey>=0 );
|
|
assert( pPage->leaf || !pPage->intKey );
|
|
|
|
TRACE(("INSERT: table=%d nkey=%lld ndata=%d page=%d %s\n",
|
|
pCur->pgnoRoot, nKey, nData, pPage->pgno,
|
|
loc==0 ? "overwrite" : "new entry"));
|
|
assert( pPage->isInit );
|
|
allocateTempSpace(pBt);
|
|
newCell = pBt->pTmpSpace;
|
|
if( newCell==0 ) return SQLITE_NOMEM;
|
|
rc = fillInCell(pPage, newCell, pKey, nKey, pData, nData, nZero, &szNew);
|
|
if( rc ) goto end_insert;
|
|
assert( szNew==cellSizePtr(pPage, newCell) );
|
|
assert( szNew<=MX_CELL_SIZE(pBt) );
|
|
idx = pCur->aiIdx[pCur->iPage];
|
|
if( loc==0 ){
|
|
u16 szOld;
|
|
assert( idx<pPage->nCell );
|
|
rc = sqlite3PagerWrite(pPage->pDbPage);
|
|
if( rc ){
|
|
goto end_insert;
|
|
}
|
|
oldCell = findCell(pPage, idx);
|
|
if( !pPage->leaf ){
|
|
memcpy(newCell, oldCell, 4);
|
|
}
|
|
szOld = cellSizePtr(pPage, oldCell);
|
|
rc = clearCell(pPage, oldCell);
|
|
dropCell(pPage, idx, szOld, &rc);
|
|
if( rc ) goto end_insert;
|
|
}else if( loc<0 && pPage->nCell>0 ){
|
|
assert( pPage->leaf );
|
|
idx = ++pCur->aiIdx[pCur->iPage];
|
|
}else{
|
|
assert( pPage->leaf );
|
|
}
|
|
insertCell(pPage, idx, newCell, szNew, 0, 0, &rc);
|
|
assert( rc!=SQLITE_OK || pPage->nCell>0 || pPage->nOverflow>0 );
|
|
|
|
/* If no error has occured and pPage has an overflow cell, call balance()
|
|
** to redistribute the cells within the tree. Since balance() may move
|
|
** the cursor, zero the BtCursor.info.nSize and BtCursor.validNKey
|
|
** variables.
|
|
**
|
|
** Previous versions of SQLite called moveToRoot() to move the cursor
|
|
** back to the root page as balance() used to invalidate the contents
|
|
** of BtCursor.apPage[] and BtCursor.aiIdx[]. Instead of doing that,
|
|
** set the cursor state to "invalid". This makes common insert operations
|
|
** slightly faster.
|
|
**
|
|
** There is a subtle but important optimization here too. When inserting
|
|
** multiple records into an intkey b-tree using a single cursor (as can
|
|
** happen while processing an "INSERT INTO ... SELECT" statement), it
|
|
** is advantageous to leave the cursor pointing to the last entry in
|
|
** the b-tree if possible. If the cursor is left pointing to the last
|
|
** entry in the table, and the next row inserted has an integer key
|
|
** larger than the largest existing key, it is possible to insert the
|
|
** row without seeking the cursor. This can be a big performance boost.
|
|
*/
|
|
pCur->info.nSize = 0;
|
|
pCur->validNKey = 0;
|
|
if( rc==SQLITE_OK && pPage->nOverflow ){
|
|
rc = balance(pCur);
|
|
|
|
/* Must make sure nOverflow is reset to zero even if the balance()
|
|
** fails. Internal data structure corruption will result otherwise.
|
|
** Also, set the cursor state to invalid. This stops saveCursorPosition()
|
|
** from trying to save the current position of the cursor. */
|
|
pCur->apPage[pCur->iPage]->nOverflow = 0;
|
|
pCur->eState = CURSOR_INVALID;
|
|
}
|
|
assert( pCur->apPage[pCur->iPage]->nOverflow==0 );
|
|
|
|
end_insert:
|
|
return rc;
|
|
}
|
|
|
|
void dumpCursor(BtCursor* c) {
|
|
int i;
|
|
printf(" Depth %d\n", c->iPage);
|
|
for(i=0; i<=c->iPage; i++)
|
|
printf(" Page %d Cell %d\n", c->apPage[i]->pgno, c->aiIdx[i]);
|
|
|
|
}
|
|
|
|
static int stackPush( int* stackBegin, int* stackEnd, int root ) {
|
|
// Push root onto the stack
|
|
stackBegin[0]++;
|
|
if (stackBegin + stackBegin[0] >= stackEnd)
|
|
return SQLITE_FULL;
|
|
stackBegin[stackBegin[0]] = root;
|
|
return SQLITE_OK;
|
|
}
|
|
|
|
SQLITE_PRIVATE int sqlite3BtreeLazyDelete(BtCursor* cursor, int* stackBegin, int* stackEnd, int desiredPages, int* pagesDeleted) {
|
|
int pageNumber, cell, rc, subtree, count;
|
|
MemPage* page;
|
|
int empty;
|
|
const void* ptr;
|
|
i64 tableKey=0;
|
|
|
|
*pagesDeleted = 0;
|
|
|
|
while (desiredPages--) {
|
|
if (!stackBegin[0]) {
|
|
// Read one or more items from the back of cursor table into stack
|
|
rc = sqlite3BtreeLast(cursor, &empty);
|
|
if (rc) return rc;
|
|
if (empty) {
|
|
// Cursor table is empty
|
|
return SQLITE_OK;
|
|
}
|
|
|
|
rc = sqlite3BtreeKeySize( cursor, &tableKey ); // actually returns the key, not the key size, in an intkey table!
|
|
if (rc) return rc;
|
|
|
|
ptr = sqlite3BtreeDataFetch( cursor, &count );
|
|
if (count != sizeof(int)) return SQLITE_CORRUPT_BKPT;
|
|
pageNumber = *(int*)ptr;
|
|
|
|
rc = sqlite3BtreeDelete(cursor);
|
|
if (rc) return rc;
|
|
} else {
|
|
// Pop (height, pageNumber) from the stack
|
|
pageNumber = stackBegin[stackBegin[0]];
|
|
stackBegin[0]--;
|
|
}
|
|
|
|
// Read the item
|
|
rc = getAndInitPage(cursor->pBt, pageNumber, &page);
|
|
if (rc) return rc;
|
|
|
|
// Put its child pages on the stack
|
|
if (!page->leaf)
|
|
for(cell = page->nCell; cell >= 0; --cell) {
|
|
if (cell == page->nCell)
|
|
subtree = get4byte( &page->aData[page->hdrOffset+8] );
|
|
else
|
|
subtree = get4byte( findCell(page, cell) );
|
|
|
|
rc = stackPush( stackBegin, stackEnd, subtree );
|
|
if (rc) { releasePage(page); return rc; }
|
|
}
|
|
|
|
// Free overflow pages
|
|
for(cell=0; cell<page->nCell; cell++) {
|
|
rc = clearCell(page, findCell(page, cell));
|
|
if( rc ) { releasePage(page); return rc; }
|
|
}
|
|
|
|
// Free it
|
|
rc = freePage2(cursor->pBt, page, pageNumber);
|
|
if (rc) { releasePage(page); return rc; }
|
|
|
|
releasePage(page); // Required after getAndInitPage() above
|
|
++(*pagesDeleted);
|
|
}
|
|
|
|
if (stackBegin[0]) {
|
|
// Get tableKey if we haven't already
|
|
if (!tableKey) {
|
|
rc = sqlite3BtreeLast(cursor, &empty);
|
|
if (rc) return rc;
|
|
|
|
if (empty)
|
|
tableKey = 1;
|
|
else {
|
|
rc = sqlite3BtreeKeySize( cursor, &tableKey );
|
|
if (rc) return rc;
|
|
++tableKey; // We aren't consuming this item so we mustn't overwrite it
|
|
}
|
|
}
|
|
|
|
// If autovacuum is enabled, update the pointer map for the root pages we are putting back in the lazy freelist table
|
|
if( cursor->pBt ){
|
|
for(count=0; count<stackBegin[0]; count++) {
|
|
rc = 0;
|
|
ptrmapPut(cursor->pBt, stackBegin[1+count], PTRMAP_LAZYFREE, 0, &rc);
|
|
if( rc ) return rc;
|
|
}
|
|
}
|
|
|
|
// Write stack onto the back of the cursor table
|
|
for(count=0; count<stackBegin[0]; count++) {
|
|
rc = sqlite3BtreeInsert( cursor, NULL, tableKey++, &stackBegin[1+count], sizeof(int), 0, 1, 0 );
|
|
if (rc) return rc;
|
|
}
|
|
}
|
|
|
|
return SQLITE_OK;
|
|
}
|
|
|
|
int deleteCellRange( MemPage* page, int beginCell, int endCell, int* stackBegin, int* stackEnd) {
|
|
unsigned char *pCell;
|
|
int rc, cell;
|
|
|
|
rc = sqlite3PagerWrite(page->pDbPage);
|
|
if( rc ) return rc;
|
|
|
|
//printf("deleteCellRange: Page %d, [%d,%d)\n", page->pgno, beginCell, endCell);
|
|
|
|
// Cells [begin, end) and their (left) subtrees will be completely deleted
|
|
// We go backward because dropCell(c) changes cell numbers >c
|
|
for(cell = endCell-1; cell >= beginCell; --cell) {
|
|
pCell = findCell(page, cell);
|
|
if (!page->leaf) {
|
|
rc = stackPush( stackBegin, stackEnd, get4byte(pCell) );
|
|
if (rc) return rc;
|
|
}
|
|
rc = clearCell(page, pCell); // free the overflow list
|
|
dropCell(page, cell, cellSizePtr(page, pCell), &rc); // free the actual cell
|
|
if( rc ) return rc;
|
|
}
|
|
return 0;
|
|
}
|
|
|
|
void swapChildren( u8* c1, u8* c2 ) {
|
|
int subtree = get4byte(c1);
|
|
put4byte( c1, get4byte(c2) );
|
|
put4byte( c2, subtree );
|
|
}
|
|
|
|
SQLITE_PRIVATE int sqlite3BtreeDeleteRange(BtCursor *begin, BtCursor *end, int* stackBegin, int* stackEnd) {
|
|
int level, cellBegin, cellEnd, rc;
|
|
MemPage *page;
|
|
BtCursor* modified = 0;
|
|
|
|
/*printf("DeleteRange\n");
|
|
printf("Begin:\n"); dumpCursor(begin);
|
|
printf("End:\n"); dumpCursor(end);*/
|
|
|
|
//if( pCur->pKeyInfo==0 ) invalidateIncrblobCursors(p, pCur->info.nKey, 0);
|
|
//rc = saveAllCursors(begin->pBt, begin->pgnoRoot, begin);
|
|
//if( rc ) return rc;
|
|
|
|
assert( begin->pgnoRoot == end->pgnoRoot );
|
|
|
|
for(level=0; level<=begin->iPage || level<=end->iPage; level++) {
|
|
if (level<=begin->iPage && level<=end->iPage && begin->apPage[level] == end->apPage[level]) {
|
|
// begin and end are still on the same page at this level. If they are on the same cell, we don't have to do anything
|
|
if (begin->aiIdx[level] != end->aiIdx[level]) {
|
|
// Don't erase the begin element in an internal node (we would have to replace it with an element from its subtree)
|
|
//cellBegin = begin->aiIdx[level] + 1;
|
|
cellBegin = begin->aiIdx[level] + !begin->apPage[level]->leaf;
|
|
cellEnd = end->aiIdx[level] + (end->iPage==level);
|
|
if (cellBegin != cellEnd) {
|
|
rc = deleteCellRange( begin->apPage[level], cellBegin, cellEnd, stackBegin, stackEnd );
|
|
if (rc) return rc;
|
|
modified = begin;
|
|
break;
|
|
}
|
|
}
|
|
} else {
|
|
if (level<=begin->iPage) {
|
|
// Erase all cells from [begin, infinity)
|
|
cellBegin = begin->aiIdx[level];
|
|
cellEnd = begin->apPage[level]->nCell;
|
|
if (cellBegin != cellEnd) {
|
|
page = begin->apPage[level];
|
|
if (!page->leaf) {
|
|
// The rightmost child pointer is located at offset 8 in the header of a non-leaf node. Swap it with the rightmost child that will remain after the erase.
|
|
swapChildren( findCell(page, cellBegin), &page->aData[page->hdrOffset+8] );
|
|
}
|
|
rc = deleteCellRange( page, cellBegin, cellEnd, stackBegin, stackEnd );
|
|
if (rc) return rc;
|
|
|
|
modified = begin;
|
|
break;
|
|
}
|
|
}
|
|
if (level<=end->iPage) {
|
|
// Erase all cells from (-infinity, end]
|
|
cellBegin = 0;
|
|
cellEnd = end->aiIdx[level]+(end->iPage==level);
|
|
if (cellBegin != cellEnd) {
|
|
rc = deleteCellRange( end->apPage[level], cellBegin, cellEnd, stackBegin, stackEnd );
|
|
if (rc) return rc;
|
|
modified = end;
|
|
break;
|
|
}
|
|
}
|
|
//assert(0);
|
|
}
|
|
}
|
|
|
|
if (!modified) {
|
|
moveToRoot(begin);
|
|
moveToRoot(end);
|
|
return SQLITE_OK;
|
|
} else {
|
|
moveToRoot( modified==begin ? end : begin );
|
|
while (modified->iPage > level) {
|
|
releasePage(modified->apPage[modified->iPage]);
|
|
--modified->iPage;
|
|
}
|
|
//printf("Balancing at page %d\n", modified->apPage[modified->iPage]->pgno);
|
|
rc = balance(modified);
|
|
if (rc) return rc;
|
|
moveToRoot(modified);
|
|
return 201;
|
|
}
|
|
}
|
|
|
|
|
|
/*
|
|
** Delete the entry that the cursor is pointing to. The cursor
|
|
** is left pointing at a arbitrary location.
|
|
*/
|
|
SQLITE_PRIVATE int sqlite3BtreeDelete(BtCursor *pCur){
|
|
Btree *p = pCur->pBtree;
|
|
BtShared *pBt = p->pBt;
|
|
int rc; /* Return code */
|
|
MemPage *pPage; /* Page to delete cell from */
|
|
unsigned char *pCell; /* Pointer to cell to delete */
|
|
int iCellIdx; /* Index of cell to delete */
|
|
int iCellDepth; /* Depth of node containing pCell */
|
|
|
|
assert( cursorHoldsMutex(pCur) );
|
|
assert( pBt->inTransaction==TRANS_WRITE );
|
|
assert( !pBt->readOnly );
|
|
assert( pCur->wrFlag );
|
|
assert( hasSharedCacheTableLock(p, pCur->pgnoRoot, pCur->pKeyInfo!=0, 2) );
|
|
assert( !hasReadConflicts(p, pCur->pgnoRoot) );
|
|
|
|
if( NEVER(pCur->aiIdx[pCur->iPage]>=pCur->apPage[pCur->iPage]->nCell)
|
|
|| NEVER(pCur->eState!=CURSOR_VALID)
|
|
){
|
|
return SQLITE_ERROR; /* Something has gone awry. */
|
|
}
|
|
|
|
/* If this is a delete operation to remove a row from a table b-tree,
|
|
** invalidate any incrblob cursors open on the row being deleted. */
|
|
if( pCur->pKeyInfo==0 ){
|
|
invalidateIncrblobCursors(p, pCur->info.nKey, 0);
|
|
}
|
|
|
|
iCellDepth = pCur->iPage;
|
|
iCellIdx = pCur->aiIdx[iCellDepth];
|
|
pPage = pCur->apPage[iCellDepth];
|
|
pCell = findCell(pPage, iCellIdx);
|
|
|
|
/* If the page containing the entry to delete is not a leaf page, move
|
|
** the cursor to the largest entry in the tree that is smaller than
|
|
** the entry being deleted. This cell will replace the cell being deleted
|
|
** from the internal node. The 'previous' entry is used for this instead
|
|
** of the 'next' entry, as the previous entry is always a part of the
|
|
** sub-tree headed by the child page of the cell being deleted. This makes
|
|
** balancing the tree following the delete operation easier. */
|
|
if( !pPage->leaf ){
|
|
int notUsed;
|
|
rc = sqlite3BtreePrevious(pCur, ¬Used);
|
|
if( rc ) return rc;
|
|
}
|
|
|
|
/* Save the positions of any other cursors open on this table before
|
|
** making any modifications. Make the page containing the entry to be
|
|
** deleted writable. Then free any overflow pages associated with the
|
|
** entry and finally remove the cell itself from within the page.
|
|
*/
|
|
rc = saveAllCursors(pBt, pCur->pgnoRoot, pCur);
|
|
if( rc ) return rc;
|
|
rc = sqlite3PagerWrite(pPage->pDbPage);
|
|
if( rc ) return rc;
|
|
rc = clearCell(pPage, pCell);
|
|
dropCell(pPage, iCellIdx, cellSizePtr(pPage, pCell), &rc);
|
|
if( rc ) return rc;
|
|
|
|
/* If the cell deleted was not located on a leaf page, then the cursor
|
|
** is currently pointing to the largest entry in the sub-tree headed
|
|
** by the child-page of the cell that was just deleted from an internal
|
|
** node. The cell from the leaf node needs to be moved to the internal
|
|
** node to replace the deleted cell. */
|
|
if( !pPage->leaf ){
|
|
MemPage *pLeaf = pCur->apPage[pCur->iPage];
|
|
int nCell;
|
|
Pgno n = pCur->apPage[iCellDepth+1]->pgno;
|
|
unsigned char *pTmp;
|
|
|
|
pCell = findCell(pLeaf, pLeaf->nCell-1);
|
|
nCell = cellSizePtr(pLeaf, pCell);
|
|
assert( MX_CELL_SIZE(pBt)>=nCell );
|
|
|
|
allocateTempSpace(pBt);
|
|
pTmp = pBt->pTmpSpace;
|
|
|
|
rc = sqlite3PagerWrite(pLeaf->pDbPage);
|
|
insertCell(pPage, iCellIdx, pCell-4, nCell+4, pTmp, n, &rc);
|
|
dropCell(pLeaf, pLeaf->nCell-1, nCell, &rc);
|
|
if( rc ) return rc;
|
|
}
|
|
|
|
/* Balance the tree. If the entry deleted was located on a leaf page,
|
|
** then the cursor still points to that page. In this case the first
|
|
** call to balance() repairs the tree, and the if(...) condition is
|
|
** never true.
|
|
**
|
|
** Otherwise, if the entry deleted was on an internal node page, then
|
|
** pCur is pointing to the leaf page from which a cell was removed to
|
|
** replace the cell deleted from the internal node. This is slightly
|
|
** tricky as the leaf node may be underfull, and the internal node may
|
|
** be either under or overfull. In this case run the balancing algorithm
|
|
** on the leaf node first. If the balance proceeds far enough up the
|
|
** tree that we can be sure that any problem in the internal node has
|
|
** been corrected, so be it. Otherwise, after balancing the leaf node,
|
|
** walk the cursor up the tree to the internal node and balance it as
|
|
** well. */
|
|
rc = balance(pCur);
|
|
if( rc==SQLITE_OK && pCur->iPage>iCellDepth ){
|
|
while( pCur->iPage>iCellDepth ){
|
|
releasePage(pCur->apPage[pCur->iPage--]);
|
|
}
|
|
rc = balance(pCur);
|
|
}
|
|
|
|
if( rc==SQLITE_OK ){
|
|
moveToRoot(pCur);
|
|
}
|
|
return rc;
|
|
}
|
|
|
|
/*
|
|
** Create a new BTree table. Write into *piTable the page
|
|
** number for the root page of the new table.
|
|
**
|
|
** The type of type is determined by the flags parameter. Only the
|
|
** following values of flags are currently in use. Other values for
|
|
** flags might not work:
|
|
**
|
|
** BTREE_INTKEY|BTREE_LEAFDATA Used for SQL tables with rowid keys
|
|
** BTREE_ZERODATA Used for SQL indices
|
|
*/
|
|
static int btreeCreateTable(Btree *p, int *piTable, int createTabFlags){
|
|
BtShared *pBt = p->pBt;
|
|
MemPage *pRoot;
|
|
Pgno pgnoRoot;
|
|
int rc;
|
|
int ptfFlags; /* Page-type flage for the root page of new table */
|
|
|
|
assert( sqlite3BtreeHoldsMutex(p) );
|
|
assert( pBt->inTransaction==TRANS_WRITE );
|
|
assert( !pBt->readOnly );
|
|
|
|
#ifdef SQLITE_OMIT_AUTOVACUUM
|
|
rc = allocateBtreePage(pBt, &pRoot, &pgnoRoot, 1, 0);
|
|
if( rc ){
|
|
return rc;
|
|
}
|
|
#else
|
|
if( pBt->autoVacuum ){
|
|
Pgno pgnoMove; /* Move a page here to make room for the root-page */
|
|
MemPage *pPageMove; /* The page to move to. */
|
|
|
|
/* Creating a new table may probably require moving an existing database
|
|
** to make room for the new tables root page. In case this page turns
|
|
** out to be an overflow page, delete all overflow page-map caches
|
|
** held by open cursors.
|
|
*/
|
|
invalidateAllOverflowCache(pBt);
|
|
|
|
/* Read the value of meta[3] from the database to determine where the
|
|
** root page of the new table should go. meta[3] is the largest root-page
|
|
** created so far, so the new root-page is (meta[3]+1).
|
|
*/
|
|
sqlite3BtreeGetMeta(p, BTREE_LARGEST_ROOT_PAGE, &pgnoRoot);
|
|
pgnoRoot++;
|
|
|
|
/* The new root-page may not be allocated on a pointer-map page, or the
|
|
** PENDING_BYTE page.
|
|
*/
|
|
while( pgnoRoot==PTRMAP_PAGENO(pBt, pgnoRoot) ||
|
|
pgnoRoot==PENDING_BYTE_PAGE(pBt) ){
|
|
pgnoRoot++;
|
|
}
|
|
assert( pgnoRoot>=3 );
|
|
|
|
/* Allocate a page. The page that currently resides at pgnoRoot will
|
|
** be moved to the allocated page (unless the allocated page happens
|
|
** to reside at pgnoRoot).
|
|
*/
|
|
rc = allocateBtreePage(pBt, &pPageMove, &pgnoMove, pgnoRoot, 1);
|
|
if( rc!=SQLITE_OK ){
|
|
return rc;
|
|
}
|
|
|
|
if( pgnoMove!=pgnoRoot ){
|
|
/* pgnoRoot is the page that will be used for the root-page of
|
|
** the new table (assuming an error did not occur). But we were
|
|
** allocated pgnoMove. If required (i.e. if it was not allocated
|
|
** by extending the file), the current page at position pgnoMove
|
|
** is already journaled.
|
|
*/
|
|
u8 eType = 0;
|
|
Pgno iPtrPage = 0;
|
|
|
|
releasePage(pPageMove);
|
|
|
|
/* Move the page currently at pgnoRoot to pgnoMove. */
|
|
rc = btreeGetPage(pBt, pgnoRoot, &pRoot, 0);
|
|
if( rc!=SQLITE_OK ){
|
|
return rc;
|
|
}
|
|
rc = ptrmapGet(pBt, pgnoRoot, &eType, &iPtrPage);
|
|
if( eType==PTRMAP_ROOTPAGE || eType==PTRMAP_FREEPAGE || eType==PTRMAP_FREELEAF ){
|
|
rc = SQLITE_CORRUPT_BKPT;
|
|
}
|
|
if( rc!=SQLITE_OK ){
|
|
releasePage(pRoot);
|
|
return rc;
|
|
}
|
|
assert( eType!=PTRMAP_ROOTPAGE );
|
|
assert( eType!=PTRMAP_FREEPAGE );
|
|
assert( eType!=PTRMAP_FREELEAF );
|
|
rc = relocatePage(pBt, pRoot, eType, iPtrPage, pgnoMove, 0);
|
|
releasePage(pRoot);
|
|
|
|
/* Obtain the page at pgnoRoot */
|
|
if( rc!=SQLITE_OK ){
|
|
return rc;
|
|
}
|
|
rc = btreeGetPage(pBt, pgnoRoot, &pRoot, 0);
|
|
if( rc!=SQLITE_OK ){
|
|
return rc;
|
|
}
|
|
rc = sqlite3PagerWrite(pRoot->pDbPage);
|
|
if( rc!=SQLITE_OK ){
|
|
releasePage(pRoot);
|
|
return rc;
|
|
}
|
|
}else{
|
|
pRoot = pPageMove;
|
|
}
|
|
|
|
/* Update the pointer-map and meta-data with the new root-page number. */
|
|
ptrmapPut(pBt, pgnoRoot, PTRMAP_ROOTPAGE, 0, &rc);
|
|
if( rc ){
|
|
releasePage(pRoot);
|
|
return rc;
|
|
}
|
|
|
|
/* When the new root page was allocated, page 1 was made writable in
|
|
** order either to increase the database filesize, or to decrement the
|
|
** freelist count. Hence, the sqlite3BtreeUpdateMeta() call cannot fail.
|
|
*/
|
|
assert( sqlite3PagerIswriteable(pBt->pPage1->pDbPage) );
|
|
rc = sqlite3BtreeUpdateMeta(p, 4, pgnoRoot);
|
|
if( NEVER(rc) ){
|
|
releasePage(pRoot);
|
|
return rc;
|
|
}
|
|
|
|
}else{
|
|
rc = allocateBtreePage(pBt, &pRoot, &pgnoRoot, 1, 0);
|
|
if( rc ) return rc;
|
|
}
|
|
#endif
|
|
assert( sqlite3PagerIswriteable(pRoot->pDbPage) );
|
|
if( createTabFlags & BTREE_INTKEY ){
|
|
ptfFlags = PTF_INTKEY | PTF_LEAFDATA | PTF_LEAF;
|
|
}else{
|
|
ptfFlags = PTF_ZERODATA | PTF_LEAF;
|
|
}
|
|
zeroPage(pRoot, ptfFlags);
|
|
sqlite3PagerUnref(pRoot->pDbPage);
|
|
assert( (pBt->openFlags & BTREE_SINGLE)==0 || pgnoRoot==2 );
|
|
*piTable = (int)pgnoRoot;
|
|
return SQLITE_OK;
|
|
}
|
|
SQLITE_PRIVATE int sqlite3BtreeCreateTable(Btree *p, int *piTable, int flags){
|
|
int rc;
|
|
sqlite3BtreeEnter(p);
|
|
rc = btreeCreateTable(p, piTable, flags);
|
|
sqlite3BtreeLeave(p);
|
|
return rc;
|
|
}
|
|
|
|
/*
|
|
** Erase the given database page and all its children. Return
|
|
** the page to the freelist.
|
|
*/
|
|
static int clearDatabasePage(
|
|
BtShared *pBt, /* The BTree that contains the table */
|
|
Pgno pgno, /* Page number to clear */
|
|
int freePageFlag, /* Deallocate page if true */
|
|
int *pnChange /* Add number of Cells freed to this counter */
|
|
){
|
|
MemPage *pPage;
|
|
int rc;
|
|
unsigned char *pCell;
|
|
int i;
|
|
|
|
assert( sqlite3_mutex_held(pBt->mutex) );
|
|
if( pgno>btreePagecount(pBt) ){
|
|
return SQLITE_CORRUPT_BKPT;
|
|
}
|
|
|
|
rc = getAndInitPage(pBt, pgno, &pPage);
|
|
if( rc ) return rc;
|
|
for(i=0; i<pPage->nCell; i++){
|
|
pCell = findCell(pPage, i);
|
|
if( !pPage->leaf ){
|
|
rc = clearDatabasePage(pBt, get4byte(pCell), 1, pnChange);
|
|
if( rc ) goto cleardatabasepage_out;
|
|
}
|
|
rc = clearCell(pPage, pCell);
|
|
if( rc ) goto cleardatabasepage_out;
|
|
}
|
|
if( !pPage->leaf ){
|
|
rc = clearDatabasePage(pBt, get4byte(&pPage->aData[8]), 1, pnChange);
|
|
if( rc ) goto cleardatabasepage_out;
|
|
}else if( pnChange ){
|
|
assert( pPage->intKey );
|
|
*pnChange += pPage->nCell;
|
|
}
|
|
if( freePageFlag ){
|
|
freePage(pPage, &rc);
|
|
}else if( (rc = sqlite3PagerWrite(pPage->pDbPage))==0 ){
|
|
zeroPage(pPage, pPage->aData[0] | PTF_LEAF);
|
|
}
|
|
|
|
cleardatabasepage_out:
|
|
releasePage(pPage);
|
|
return rc;
|
|
}
|
|
|
|
/*
|
|
** Delete all information from a single table in the database. iTable is
|
|
** the page number of the root of the table. After this routine returns,
|
|
** the root page is empty, but still exists.
|
|
**
|
|
** This routine will fail with SQLITE_LOCKED if there are any open
|
|
** read cursors on the table. Open write cursors are moved to the
|
|
** root of the table.
|
|
**
|
|
** If pnChange is not NULL, then table iTable must be an intkey table. The
|
|
** integer value pointed to by pnChange is incremented by the number of
|
|
** entries in the table.
|
|
*/
|
|
SQLITE_PRIVATE int sqlite3BtreeClearTable(Btree *p, int iTable, int *pnChange){
|
|
int rc;
|
|
BtShared *pBt = p->pBt;
|
|
sqlite3BtreeEnter(p);
|
|
assert( p->inTrans==TRANS_WRITE );
|
|
|
|
/* Invalidate all incrblob cursors open on table iTable (assuming iTable
|
|
** is the root of a table b-tree - if it is not, the following call is
|
|
** a no-op). */
|
|
invalidateIncrblobCursors(p, 0, 1);
|
|
|
|
rc = saveAllCursors(pBt, (Pgno)iTable, 0);
|
|
if( SQLITE_OK==rc ){
|
|
rc = clearDatabasePage(pBt, (Pgno)iTable, 0, pnChange);
|
|
}
|
|
sqlite3BtreeLeave(p);
|
|
return rc;
|
|
}
|
|
|
|
/*
|
|
** Erase all information in a table and add the root of the table to
|
|
** the freelist. Except, the root of the principle table (the one on
|
|
** page 1) is never added to the freelist.
|
|
**
|
|
** This routine will fail with SQLITE_LOCKED if there are any open
|
|
** cursors on the table.
|
|
**
|
|
** If AUTOVACUUM is enabled and the page at iTable is not the last
|
|
** root page in the database file, then the last root page
|
|
** in the database file is moved into the slot formerly occupied by
|
|
** iTable and that last slot formerly occupied by the last root page
|
|
** is added to the freelist instead of iTable. In this say, all
|
|
** root pages are kept at the beginning of the database file, which
|
|
** is necessary for AUTOVACUUM to work right. *piMoved is set to the
|
|
** page number that used to be the last root page in the file before
|
|
** the move. If no page gets moved, *piMoved is set to 0.
|
|
** The last root page is recorded in meta[3] and the value of
|
|
** meta[3] is updated by this procedure.
|
|
*/
|
|
static int btreeDropTable(Btree *p, Pgno iTable, int *piMoved){
|
|
int rc;
|
|
MemPage *pPage = 0;
|
|
BtShared *pBt = p->pBt;
|
|
|
|
assert( sqlite3BtreeHoldsMutex(p) );
|
|
assert( p->inTrans==TRANS_WRITE );
|
|
|
|
/* It is illegal to drop a table if any cursors are open on the
|
|
** database. This is because in auto-vacuum mode the backend may
|
|
** need to move another root-page to fill a gap left by the deleted
|
|
** root page. If an open cursor was using this page a problem would
|
|
** occur.
|
|
**
|
|
** This error is caught long before control reaches this point.
|
|
*/
|
|
if( NEVER(pBt->pCursor) ){
|
|
sqlite3ConnectionBlocked(p->db, pBt->pCursor->pBtree->db);
|
|
return SQLITE_LOCKED_SHAREDCACHE;
|
|
}
|
|
|
|
rc = btreeGetPage(pBt, (Pgno)iTable, &pPage, 0);
|
|
if( rc ) return rc;
|
|
rc = sqlite3BtreeClearTable(p, iTable, 0);
|
|
if( rc ){
|
|
releasePage(pPage);
|
|
return rc;
|
|
}
|
|
|
|
*piMoved = 0;
|
|
|
|
if( iTable>1 ){
|
|
#ifdef SQLITE_OMIT_AUTOVACUUM
|
|
freePage(pPage, &rc);
|
|
releasePage(pPage);
|
|
#else
|
|
if( pBt->autoVacuum ){
|
|
Pgno maxRootPgno;
|
|
sqlite3BtreeGetMeta(p, BTREE_LARGEST_ROOT_PAGE, &maxRootPgno);
|
|
|
|
if( iTable==maxRootPgno ){
|
|
/* If the table being dropped is the table with the largest root-page
|
|
** number in the database, put the root page on the free list.
|
|
*/
|
|
freePage(pPage, &rc);
|
|
releasePage(pPage);
|
|
if( rc!=SQLITE_OK ){
|
|
return rc;
|
|
}
|
|
}else{
|
|
/* The table being dropped does not have the largest root-page
|
|
** number in the database. So move the page that does into the
|
|
** gap left by the deleted root-page.
|
|
*/
|
|
MemPage *pMove;
|
|
releasePage(pPage);
|
|
rc = btreeGetPage(pBt, maxRootPgno, &pMove, 0);
|
|
if( rc!=SQLITE_OK ){
|
|
return rc;
|
|
}
|
|
rc = relocatePage(pBt, pMove, PTRMAP_ROOTPAGE, 0, iTable, 0);
|
|
releasePage(pMove);
|
|
if( rc!=SQLITE_OK ){
|
|
return rc;
|
|
}
|
|
pMove = 0;
|
|
rc = btreeGetPage(pBt, maxRootPgno, &pMove, 0);
|
|
freePage(pMove, &rc);
|
|
releasePage(pMove);
|
|
if( rc!=SQLITE_OK ){
|
|
return rc;
|
|
}
|
|
*piMoved = maxRootPgno;
|
|
}
|
|
|
|
/* Set the new 'max-root-page' value in the database header. This
|
|
** is the old value less one, less one more if that happens to
|
|
** be a root-page number, less one again if that is the
|
|
** PENDING_BYTE_PAGE.
|
|
*/
|
|
maxRootPgno--;
|
|
while( maxRootPgno==PENDING_BYTE_PAGE(pBt)
|
|
|| PTRMAP_ISPAGE(pBt, maxRootPgno) ){
|
|
maxRootPgno--;
|
|
}
|
|
assert( maxRootPgno!=PENDING_BYTE_PAGE(pBt) );
|
|
|
|
rc = sqlite3BtreeUpdateMeta(p, 4, maxRootPgno);
|
|
}else{
|
|
freePage(pPage, &rc);
|
|
releasePage(pPage);
|
|
}
|
|
#endif
|
|
}else{
|
|
/* If sqlite3BtreeDropTable was called on page 1.
|
|
** This really never should happen except in a corrupt
|
|
** database.
|
|
*/
|
|
zeroPage(pPage, PTF_INTKEY|PTF_LEAF );
|
|
releasePage(pPage);
|
|
}
|
|
return rc;
|
|
}
|
|
SQLITE_PRIVATE int sqlite3BtreeDropTable(Btree *p, int iTable, int *piMoved){
|
|
int rc;
|
|
sqlite3BtreeEnter(p);
|
|
rc = btreeDropTable(p, iTable, piMoved);
|
|
sqlite3BtreeLeave(p);
|
|
return rc;
|
|
}
|
|
|
|
|
|
/*
|
|
** This function may only be called if the b-tree connection already
|
|
** has a read or write transaction open on the database.
|
|
**
|
|
** Read the meta-information out of a database file. Meta[0]
|
|
** is the number of free pages currently in the database. Meta[1]
|
|
** through meta[15] are available for use by higher layers. Meta[0]
|
|
** is read-only, the others are read/write.
|
|
**
|
|
** The schema layer numbers meta values differently. At the schema
|
|
** layer (and the SetCookie and ReadCookie opcodes) the number of
|
|
** free pages is not visible. So Cookie[0] is the same as Meta[1].
|
|
*/
|
|
SQLITE_PRIVATE void sqlite3BtreeGetMeta(Btree *p, int idx, u32 *pMeta){
|
|
BtShared *pBt = p->pBt;
|
|
|
|
sqlite3BtreeEnter(p);
|
|
assert( p->inTrans>TRANS_NONE );
|
|
assert( SQLITE_OK==querySharedCacheTableLock(p, MASTER_ROOT, READ_LOCK) );
|
|
assert( pBt->pPage1 );
|
|
assert( idx>=0 && idx<=15 );
|
|
|
|
*pMeta = get4byte(&pBt->pPage1->aData[36 + idx*4]);
|
|
|
|
/* If auto-vacuum is disabled in this build and this is an auto-vacuum
|
|
** database, mark the database as read-only. */
|
|
#ifdef SQLITE_OMIT_AUTOVACUUM
|
|
if( idx==BTREE_LARGEST_ROOT_PAGE && *pMeta>0 ) pBt->readOnly = 1;
|
|
#endif
|
|
|
|
sqlite3BtreeLeave(p);
|
|
}
|
|
|
|
/*
|
|
** Write meta-information back into the database. Meta[0] is
|
|
** read-only and may not be written.
|
|
*/
|
|
SQLITE_PRIVATE int sqlite3BtreeUpdateMeta(Btree *p, int idx, u32 iMeta){
|
|
BtShared *pBt = p->pBt;
|
|
unsigned char *pP1;
|
|
int rc;
|
|
assert( idx>=1 && idx<=15 );
|
|
sqlite3BtreeEnter(p);
|
|
assert( p->inTrans==TRANS_WRITE );
|
|
assert( pBt->pPage1!=0 );
|
|
pP1 = pBt->pPage1->aData;
|
|
rc = sqlite3PagerWrite(pBt->pPage1->pDbPage);
|
|
if( rc==SQLITE_OK ){
|
|
put4byte(&pP1[36 + idx*4], iMeta);
|
|
#ifndef SQLITE_OMIT_AUTOVACUUM
|
|
if( idx==BTREE_INCR_VACUUM ){
|
|
assert( pBt->autoVacuum || iMeta==0 );
|
|
assert( iMeta==0 || iMeta==1 );
|
|
pBt->incrVacuum = (u8)iMeta;
|
|
}
|
|
#endif
|
|
}
|
|
sqlite3BtreeLeave(p);
|
|
return rc;
|
|
}
|
|
|
|
#ifndef SQLITE_OMIT_BTREECOUNT
|
|
/*
|
|
** The first argument, pCur, is a cursor opened on some b-tree. Count the
|
|
** number of entries in the b-tree and write the result to *pnEntry.
|
|
**
|
|
** SQLITE_OK is returned if the operation is successfully executed.
|
|
** Otherwise, if an error is encountered (i.e. an IO error or database
|
|
** corruption) an SQLite error code is returned.
|
|
*/
|
|
SQLITE_PRIVATE int sqlite3BtreeCount(BtCursor *pCur, i64 *pnEntry){
|
|
i64 nEntry = 0; /* Value to return in *pnEntry */
|
|
int rc; /* Return code */
|
|
rc = moveToRoot(pCur);
|
|
|
|
/* Unless an error occurs, the following loop runs one iteration for each
|
|
** page in the B-Tree structure (not including overflow pages).
|
|
*/
|
|
while( rc==SQLITE_OK ){
|
|
int iIdx; /* Index of child node in parent */
|
|
MemPage *pPage; /* Current page of the b-tree */
|
|
|
|
/* If this is a leaf page or the tree is not an int-key tree, then
|
|
** this page contains countable entries. Increment the entry counter
|
|
** accordingly.
|
|
*/
|
|
pPage = pCur->apPage[pCur->iPage];
|
|
if( pPage->leaf || !pPage->intKey ){
|
|
nEntry += pPage->nCell;
|
|
}
|
|
|
|
/* pPage is a leaf node. This loop navigates the cursor so that it
|
|
** points to the first interior cell that it points to the parent of
|
|
** the next page in the tree that has not yet been visited. The
|
|
** pCur->aiIdx[pCur->iPage] value is set to the index of the parent cell
|
|
** of the page, or to the number of cells in the page if the next page
|
|
** to visit is the right-child of its parent.
|
|
**
|
|
** If all pages in the tree have been visited, return SQLITE_OK to the
|
|
** caller.
|
|
*/
|
|
if( pPage->leaf ){
|
|
do {
|
|
if( pCur->iPage==0 ){
|
|
/* All pages of the b-tree have been visited. Return successfully. */
|
|
*pnEntry = nEntry;
|
|
return SQLITE_OK;
|
|
}
|
|
moveToParent(pCur);
|
|
}while ( pCur->aiIdx[pCur->iPage]>=pCur->apPage[pCur->iPage]->nCell );
|
|
|
|
pCur->aiIdx[pCur->iPage]++;
|
|
pPage = pCur->apPage[pCur->iPage];
|
|
}
|
|
|
|
/* Descend to the child node of the cell that the cursor currently
|
|
** points at. This is the right-child if (iIdx==pPage->nCell).
|
|
*/
|
|
iIdx = pCur->aiIdx[pCur->iPage];
|
|
if( iIdx==pPage->nCell ){
|
|
rc = moveToChild(pCur, get4byte(&pPage->aData[pPage->hdrOffset+8]));
|
|
}else{
|
|
rc = moveToChild(pCur, get4byte(findCell(pPage, iIdx)));
|
|
}
|
|
}
|
|
|
|
/* An error has occurred. Return an error code. */
|
|
return rc;
|
|
}
|
|
#endif
|
|
|
|
/*
|
|
** Return the pager associated with a BTree. This routine is used for
|
|
** testing and debugging only.
|
|
*/
|
|
SQLITE_PRIVATE Pager *sqlite3BtreePager(Btree *p){
|
|
return p->pBt->pPager;
|
|
}
|
|
|
|
#ifndef SQLITE_OMIT_INTEGRITY_CHECK
|
|
/*
|
|
** Append a message to the error message string.
|
|
*/
|
|
static void checkAppendMsg(
|
|
IntegrityCk *pCheck,
|
|
char *zMsg1,
|
|
const char *zFormat,
|
|
...
|
|
){
|
|
va_list ap;
|
|
if( !pCheck->mxErr ) return;
|
|
pCheck->mxErr--;
|
|
pCheck->nErr++;
|
|
va_start(ap, zFormat);
|
|
if( pCheck->errMsg.nChar ){
|
|
sqlite3StrAccumAppend(&pCheck->errMsg, "\n", 1);
|
|
}
|
|
if( zMsg1 ){
|
|
sqlite3StrAccumAppend(&pCheck->errMsg, zMsg1, -1);
|
|
}
|
|
sqlite3VXPrintf(&pCheck->errMsg, 1, zFormat, ap);
|
|
va_end(ap);
|
|
if( pCheck->errMsg.mallocFailed ){
|
|
pCheck->mallocFailed = 1;
|
|
}
|
|
}
|
|
#endif /* SQLITE_OMIT_INTEGRITY_CHECK */
|
|
|
|
#ifndef SQLITE_OMIT_INTEGRITY_CHECK
|
|
/*
|
|
** Add 1 to the reference count for page iPage. If this is the second
|
|
** reference to the page, add an error message to pCheck->zErrMsg.
|
|
** Return 1 if there are 2 ore more references to the page and 0 if
|
|
** if this is the first reference to the page.
|
|
**
|
|
** Also check that the page number is in bounds.
|
|
*/
|
|
static int checkRef(IntegrityCk *pCheck, Pgno iPage, char *zContext){
|
|
if( iPage==0 ) return 1;
|
|
if( iPage>pCheck->nPage ){
|
|
checkAppendMsg(pCheck, zContext, "invalid page number %d", iPage);
|
|
return 1;
|
|
}
|
|
if( pCheck->anRef[iPage]==1 ){
|
|
checkAppendMsg(pCheck, zContext, "2nd reference to page %d", iPage);
|
|
return 1;
|
|
}
|
|
return (pCheck->anRef[iPage]++)>1;
|
|
}
|
|
|
|
#ifndef SQLITE_OMIT_AUTOVACUUM
|
|
/*
|
|
** Check that the entry in the pointer-map for page iChild maps to
|
|
** page iParent, pointer type ptrType. If not, append an error message
|
|
** to pCheck.
|
|
*/
|
|
static void checkPtrmap(
|
|
IntegrityCk *pCheck, /* Integrity check context */
|
|
Pgno iChild, /* Child page number */
|
|
u8 eType, /* Expected pointer map type */
|
|
Pgno iParent, /* Expected pointer map parent page number */
|
|
char *zContext /* Context description (used for error msg) */
|
|
){
|
|
int rc;
|
|
u8 ePtrmapType;
|
|
Pgno iPtrmapParent;
|
|
|
|
rc = ptrmapGet(pCheck->pBt, iChild, &ePtrmapType, &iPtrmapParent);
|
|
if( rc!=SQLITE_OK ){
|
|
if( rc==SQLITE_NOMEM || rc==SQLITE_IOERR_NOMEM ) pCheck->mallocFailed = 1;
|
|
checkAppendMsg(pCheck, zContext, "Failed to read ptrmap key=%d", iChild);
|
|
return;
|
|
}
|
|
|
|
if( ePtrmapType!=eType || iPtrmapParent!=iParent ){
|
|
checkAppendMsg(pCheck, zContext,
|
|
"Bad ptr map entry key=%d expected=(%d,%d) got=(%d,%d)",
|
|
iChild, eType, iParent, ePtrmapType, iPtrmapParent);
|
|
}
|
|
}
|
|
#endif
|
|
|
|
/*
|
|
** Check the integrity of the freelist or of an overflow page list.
|
|
** Verify that the number of pages on the list is N.
|
|
*/
|
|
static void checkList(
|
|
IntegrityCk *pCheck, /* Integrity checking context */
|
|
int isFreeList, /* True for a freelist. False for overflow page list */
|
|
int iPage, /* Page number for first page in the list */
|
|
int N, /* Expected number of pages in the list */
|
|
char *zContext /* Context for error messages */
|
|
){
|
|
int i;
|
|
int expected = N;
|
|
int iFirst = iPage;
|
|
int prevPage = 0;
|
|
while( N > 0 && pCheck->mxErr ){
|
|
N--; // this trunk page is free
|
|
DbPage *pOvflPage;
|
|
unsigned char *pOvflData;
|
|
if( iPage<1 ){
|
|
checkAppendMsg(pCheck, zContext,
|
|
"%d of %d pages missing from overflow list starting at %d",
|
|
N+1, expected, iFirst);
|
|
break;
|
|
}
|
|
if( checkRef(pCheck, iPage, zContext) ) break;
|
|
if( sqlite3PagerGet(pCheck->pPager, (Pgno)iPage, &pOvflPage) ){
|
|
checkAppendMsg(pCheck, zContext, "failed to get page %d", iPage);
|
|
break;
|
|
}
|
|
pOvflData = (unsigned char *)sqlite3PagerGetData(pOvflPage);
|
|
if( isFreeList ){
|
|
int n = get4byte(&pOvflData[4]);
|
|
#ifndef SQLITE_OMIT_AUTOVACUUM
|
|
if( pCheck->pBt->autoVacuum && g_expect_full_pointermap ){
|
|
checkPtrmap(pCheck, iPage, PTRMAP_FREEPAGE, prevPage, zContext);
|
|
}
|
|
#endif
|
|
if( n>(int)pCheck->pBt->usableSize/4-2 ){
|
|
checkAppendMsg(pCheck, zContext,
|
|
"freelist leaf count too big on page %d", iPage);
|
|
}else{
|
|
for(i=0; i<n; i++){
|
|
Pgno iFreePage = get4byte(&pOvflData[8+i*4]);
|
|
if (iFreePage <= pCheck->nPage) {
|
|
#ifndef SQLITE_OMIT_AUTOVACUUM
|
|
if( pCheck->pBt->autoVacuum && g_expect_full_pointermap ){
|
|
checkPtrmap(pCheck, iFreePage, PTRMAP_FREELEAF, 0, zContext);
|
|
}
|
|
#endif
|
|
checkRef(pCheck, iFreePage, zContext);
|
|
N--; // this leaf page is free
|
|
}
|
|
}
|
|
}
|
|
}
|
|
#ifndef SQLITE_OMIT_AUTOVACUUM
|
|
else{
|
|
/* If this database supports auto-vacuum and iPage is not the last
|
|
** page in this overflow list, check that the pointer-map entry for
|
|
** the following page matches iPage.
|
|
*/
|
|
if( pCheck->pBt->autoVacuum && N>0 ){
|
|
i = get4byte(pOvflData);
|
|
checkPtrmap(pCheck, i, PTRMAP_OVERFLOW2, iPage, zContext);
|
|
}
|
|
}
|
|
#endif
|
|
prevPage = iPage;
|
|
iPage = get4byte(pOvflData);
|
|
sqlite3PagerUnref(pOvflPage);
|
|
}
|
|
if (iPage>=1)
|
|
checkAppendMsg(pCheck, zContext, "extra trunk pages on freelist");
|
|
if (N < 0)
|
|
checkAppendMsg(pCheck, zContext, "too many pages found on freelist");
|
|
}
|
|
#endif /* SQLITE_OMIT_INTEGRITY_CHECK */
|
|
|
|
#ifndef SQLITE_OMIT_INTEGRITY_CHECK
|
|
/*
|
|
** Do various sanity checks on a single page of a tree. Return
|
|
** the tree depth. Root pages return 0. Parents of root pages
|
|
** return 1, and so forth.
|
|
**
|
|
** These checks are done:
|
|
**
|
|
** 1. Make sure that cells and freeblocks do not overlap
|
|
** but combine to completely cover the page.
|
|
** NO 2. Make sure cell keys are in order.
|
|
** NO 3. Make sure no key is less than or equal to zLowerBound.
|
|
** NO 4. Make sure no key is greater than or equal to zUpperBound.
|
|
** 5. Check the integrity of overflow pages.
|
|
** 6. Recursively call checkTreePage on all children.
|
|
** 7. Verify that the depth of all children is the same.
|
|
** 8. Make sure this page is at least 33% full or else it is
|
|
** the root of the tree.
|
|
*/
|
|
static int checkTreePage(
|
|
IntegrityCk *pCheck, /* Context for the sanity check */
|
|
int iPage, /* Page number of the page to check */
|
|
char *zParentContext, /* Parent context */
|
|
i64 *pnParentMinKey,
|
|
i64 *pnParentMaxKey,
|
|
int verbose,
|
|
int isRoot,
|
|
int iRootPage
|
|
){
|
|
MemPage *pPage;
|
|
int i, rc, depth, d2, pgno, cnt;
|
|
int hdr, cellStart;
|
|
int nCell;
|
|
u8 *data;
|
|
BtShared *pBt;
|
|
int usableSize;
|
|
char zContext[100];
|
|
char *hit = 0;
|
|
i64 nMinKey = 0;
|
|
i64 nMaxKey = 0;
|
|
|
|
sqlite3_snprintf(sizeof(zContext), zContext, "Page %d of tree %d: ", iPage, iRootPage);
|
|
//if (verbose) printf("Page %d\n", iPage);
|
|
|
|
/* Check that the page exists
|
|
*/
|
|
pBt = pCheck->pBt;
|
|
usableSize = pBt->usableSize;
|
|
if( iPage==0 ) return 0;
|
|
if( checkRef(pCheck, iPage, zParentContext) ) return 0;
|
|
if( (rc = btreeGetPage(pBt, (Pgno)iPage, &pPage, 0))!=0 ){
|
|
checkAppendMsg(pCheck, zContext,
|
|
"unable to get the page. error code=%d", rc);
|
|
return 0;
|
|
}
|
|
|
|
/* Clear MemPage.isInit to make sure the corruption detection code in
|
|
** btreeInitPage() is executed. */
|
|
pPage->isInit = 0;
|
|
if( (rc = btreeInitPage(pPage))!=0 ){
|
|
assert( rc==SQLITE_CORRUPT ); /* The only possible error from InitPage */
|
|
checkAppendMsg(pCheck, zContext,
|
|
"btreeInitPage() returns error code %d", rc);
|
|
releasePage(pPage);
|
|
return 0;
|
|
}
|
|
|
|
/* Check that the page is balanced unless it is the root */
|
|
// FIXME: This check fails for us, probably it is a (performance) bug!
|
|
/*if (!isRoot &&
|
|
pPage->nFree > pCheck->pBt->usableSize * 2 / 3) {
|
|
checkAppendMsg(pCheck, zContext,
|
|
"Page underfull (%d/%d free)", pPage->nFree, pCheck->pBt->usableSize);
|
|
}*/
|
|
//pPage->nOverflow==0 && pPage->nFree<=nMin
|
|
|
|
/* Check out all the cells.
|
|
*/
|
|
depth = 0;
|
|
for(i=0; i<pPage->nCell && pCheck->mxErr; i++){
|
|
u8 *pCell;
|
|
u32 sz;
|
|
CellInfo info;
|
|
|
|
/* Check payload overflow pages
|
|
*/
|
|
sqlite3_snprintf(sizeof(zContext), zContext,
|
|
"On tree page %d cell %d: ", iPage, i);
|
|
pCell = findCell(pPage,i);
|
|
btreeParseCellPtr(pPage, pCell, &info);
|
|
sz = info.nData;
|
|
if( !pPage->intKey ) sz += (int)info.nKey;
|
|
/* For intKey pages, check that the keys are in order.
|
|
*/
|
|
else if( i==0 ) nMinKey = nMaxKey = info.nKey;
|
|
else{
|
|
if( info.nKey <= nMaxKey ){
|
|
checkAppendMsg(pCheck, zContext,
|
|
"Rowid %lld out of order (previous was %lld)", info.nKey, nMaxKey);
|
|
}
|
|
nMaxKey = info.nKey;
|
|
}
|
|
assert( sz==info.nPayload );
|
|
if( (sz>info.nLocal)
|
|
&& (&pCell[info.iOverflow]<=&pPage->aData[pBt->usableSize])
|
|
){
|
|
int nPage = (sz - info.nLocal + usableSize - 5)/(usableSize - 4);
|
|
Pgno pgnoOvfl = get4byte(&pCell[info.iOverflow]);
|
|
#ifndef SQLITE_OMIT_AUTOVACUUM
|
|
if( pBt->autoVacuum ){
|
|
checkPtrmap(pCheck, pgnoOvfl, PTRMAP_OVERFLOW1, iPage, zContext);
|
|
}
|
|
#endif
|
|
checkList(pCheck, 0, pgnoOvfl, nPage, zContext);
|
|
}
|
|
|
|
/* Check sanity of left child page.
|
|
*/
|
|
if( !pPage->leaf ){
|
|
pgno = get4byte(pCell);
|
|
#ifndef SQLITE_OMIT_AUTOVACUUM
|
|
if( pBt->autoVacuum ){
|
|
checkPtrmap(pCheck, pgno, PTRMAP_BTREE, iPage, zContext);
|
|
}
|
|
#endif
|
|
d2 = checkTreePage(pCheck, pgno, zContext, &nMinKey, i==0 ? NULL : &nMaxKey, verbose, 0, iRootPage);
|
|
if( i>0 && d2!=depth ){
|
|
checkAppendMsg(pCheck, zContext, "Child page depth differs");
|
|
}
|
|
depth = d2;
|
|
}
|
|
if (verbose) {
|
|
for(d2=0; d2<depth; d2++)
|
|
printf(" : ");
|
|
printf("'%c' ", pCell[info.nHeader+4]);
|
|
printf(" Page %d Cell %d\n", iPage, i);
|
|
}
|
|
}
|
|
|
|
if( !pPage->leaf ){
|
|
pgno = get4byte(&pPage->aData[pPage->hdrOffset+8]);
|
|
sqlite3_snprintf(sizeof(zContext), zContext,
|
|
"On page %d at right child: ", iPage);
|
|
#ifndef SQLITE_OMIT_AUTOVACUUM
|
|
if( pBt->autoVacuum ){
|
|
checkPtrmap(pCheck, pgno, PTRMAP_BTREE, iPage, zContext);
|
|
}
|
|
#endif
|
|
checkTreePage(pCheck, pgno, zContext, NULL, !pPage->nCell ? NULL : &nMaxKey, verbose, 0, iRootPage);
|
|
}
|
|
|
|
/* For intKey leaf pages, check that the min/max keys are in order
|
|
** with any left/parent/right pages.
|
|
*/
|
|
if( pPage->leaf && pPage->intKey ){
|
|
/* if we are a left child page */
|
|
if( pnParentMinKey ){
|
|
/* if we are the left most child page */
|
|
if( !pnParentMaxKey ){
|
|
if( nMaxKey > *pnParentMinKey ){
|
|
checkAppendMsg(pCheck, zContext,
|
|
"Rowid %lld out of order (max larger than parent min of %lld)",
|
|
nMaxKey, *pnParentMinKey);
|
|
}
|
|
}else{
|
|
if( nMinKey <= *pnParentMinKey ){
|
|
checkAppendMsg(pCheck, zContext,
|
|
"Rowid %lld out of order (min less than parent min of %lld)",
|
|
nMinKey, *pnParentMinKey);
|
|
}
|
|
if( nMaxKey > *pnParentMaxKey ){
|
|
checkAppendMsg(pCheck, zContext,
|
|
"Rowid %lld out of order (max larger than parent max of %lld)",
|
|
nMaxKey, *pnParentMaxKey);
|
|
}
|
|
*pnParentMinKey = nMaxKey;
|
|
}
|
|
/* else if we're a right child page */
|
|
} else if( pnParentMaxKey ){
|
|
if( nMinKey <= *pnParentMaxKey ){
|
|
checkAppendMsg(pCheck, zContext,
|
|
"Rowid %lld out of order (min less than parent max of %lld)",
|
|
nMinKey, *pnParentMaxKey);
|
|
}
|
|
}
|
|
}
|
|
|
|
/* Check for complete coverage of the page
|
|
*/
|
|
data = pPage->aData;
|
|
hdr = pPage->hdrOffset;
|
|
hit = sqlite3PageMalloc( pBt->pageSize );
|
|
if( hit==0 ){
|
|
pCheck->mallocFailed = 1;
|
|
}else{
|
|
int contentOffset = get2byteNotZero(&data[hdr+5]);
|
|
assert( contentOffset<=usableSize ); /* Enforced by btreeInitPage() */
|
|
memset(hit+contentOffset, 0, usableSize-contentOffset);
|
|
memset(hit, 1, contentOffset);
|
|
nCell = get2byte(&data[hdr+3]);
|
|
cellStart = hdr + 12 - 4*pPage->leaf;
|
|
for(i=0; i<nCell; i++){
|
|
int pc = get2byte(&data[cellStart+i*2]);
|
|
u32 size = 65536;
|
|
int j;
|
|
if( pc<=usableSize-4 ){
|
|
size = cellSizePtr(pPage, &data[pc]);
|
|
}
|
|
if( (int)(pc+size-1)>=usableSize ){
|
|
checkAppendMsg(pCheck, 0,
|
|
"Corruption detected in cell %d on page %d",i,iPage);
|
|
}else{
|
|
for(j=pc+size-1; j>=pc; j--) hit[j]++;
|
|
}
|
|
}
|
|
i = get2byte(&data[hdr+1]);
|
|
while( i>0 ){
|
|
int size, j;
|
|
assert( i<=usableSize-4 ); /* Enforced by btreeInitPage() */
|
|
size = get2byte(&data[i+2]);
|
|
assert( i+size<=usableSize ); /* Enforced by btreeInitPage() */
|
|
for(j=i+size-1; j>=i; j--) hit[j]++;
|
|
j = get2byte(&data[i]);
|
|
assert( j==0 || j>i+size ); /* Enforced by btreeInitPage() */
|
|
assert( j<=usableSize-4 ); /* Enforced by btreeInitPage() */
|
|
i = j;
|
|
}
|
|
for(i=cnt=0; i<usableSize; i++){
|
|
if( hit[i]==0 ){
|
|
cnt++;
|
|
}else if( hit[i]>1 ){
|
|
checkAppendMsg(pCheck, 0,
|
|
"Multiple uses for byte %d of page %d", i, iPage);
|
|
break;
|
|
}
|
|
}
|
|
if( cnt!=data[hdr+7] ){
|
|
checkAppendMsg(pCheck, 0,
|
|
"Fragmentation of %d bytes reported as %d on page %d",
|
|
cnt, data[hdr+7], iPage);
|
|
}
|
|
}
|
|
sqlite3PageFree(hit);
|
|
releasePage(pPage);
|
|
return depth+1;
|
|
}
|
|
#endif /* SQLITE_OMIT_INTEGRITY_CHECK */
|
|
|
|
#ifndef SQLITE_OMIT_INTEGRITY_CHECK
|
|
static int checkLazyDeleteTable(Btree* bt, IntegrityCk *ck, int tableRoot) {
|
|
BtCursor cursor;
|
|
int empty;
|
|
int rc;
|
|
i64 tableKey;
|
|
int count;
|
|
const void* ptr;
|
|
int pageNumber;
|
|
|
|
sqlite3BtreeCursorZero(&cursor);
|
|
|
|
if ((rc=sqlite3BtreeCursor(bt, tableRoot, 0, NULL, &cursor))) {
|
|
checkAppendMsg(ck, 0, "Unable to open cursor for lazy delete table check: %d", rc);
|
|
return rc;
|
|
}
|
|
|
|
if ((rc=sqlite3BtreeFirst(&cursor, &empty))) {
|
|
checkAppendMsg(ck, 0, "sqlite3BtreeFirst: %d", rc);
|
|
sqlite3BtreeCloseCursor(&cursor);
|
|
return rc;
|
|
}
|
|
|
|
while (!empty) {
|
|
rc = sqlite3BtreeKeySize( &cursor, &tableKey ); // actually returns the key, not the key size, in an intkey table!
|
|
if (rc) {
|
|
checkAppendMsg(ck, 0, "sqlite3BtreeKeySize: %d", rc);
|
|
sqlite3BtreeCloseCursor(&cursor);
|
|
return rc;
|
|
}
|
|
|
|
ptr = sqlite3BtreeDataFetch( &cursor, &count );
|
|
if (count != sizeof(int)) return SQLITE_CORRUPT_BKPT;
|
|
pageNumber = *(int*)ptr;
|
|
|
|
checkPtrmap(ck, pageNumber, PTRMAP_LAZYFREE, 0, "lazy delete");
|
|
checkTreePage(ck, pageNumber, "lazily deleted", NULL, NULL, 0, 0, pageNumber);
|
|
|
|
if ((rc=sqlite3BtreeNext(&cursor, &empty))) {
|
|
checkAppendMsg(ck, 0, "sqlite3BtreeNext: %d", rc);
|
|
sqlite3BtreeCloseCursor(&cursor);
|
|
return rc;
|
|
}
|
|
}
|
|
|
|
sqlite3BtreeCloseCursor(&cursor);
|
|
return 0;
|
|
}
|
|
#endif /* SQLITE_OMIT_INTEGRITY_CHECK */
|
|
|
|
#ifndef SQLITE_OMIT_INTEGRITY_CHECK
|
|
/*
|
|
** This routine does a complete check of the given BTree file. aRoot[] is
|
|
** an array of pages numbers were each page number is the root page of
|
|
** a table. nRoot is the number of entries in aRoot.
|
|
**
|
|
** A read-only or read-write transaction must be opened before calling
|
|
** this function.
|
|
**
|
|
** Write the number of error seen in *pnErr. Except for some memory
|
|
** allocation errors, an error message held in memory obtained from
|
|
** malloc is returned if *pnErr is non-zero. If *pnErr==0 then NULL is
|
|
** returned. If a memory allocation error occurs, NULL is returned.
|
|
*/
|
|
SQLITE_PRIVATE char *sqlite3BtreeIntegrityCheck(
|
|
Btree *p, /* The btree to be checked */
|
|
int *aRoot, /* An array of root pages numbers for individual trees */
|
|
int nRoot, /* Number of entries in aRoot[] */
|
|
int mxErr, /* Stop reporting errors after this many */
|
|
int *pnErr, /* Write number of errors seen to this variable */
|
|
int verbose /* Nonzero to print entire tree */
|
|
){
|
|
Pgno i;
|
|
int nRef;
|
|
IntegrityCk sCheck;
|
|
BtShared *pBt = p->pBt;
|
|
char zErr[100];
|
|
u8 eType;
|
|
Pgno iPtrPage;
|
|
|
|
|
|
sqlite3BtreeEnter(p);
|
|
assert( p->inTrans>TRANS_NONE && pBt->inTransaction>TRANS_NONE );
|
|
nRef = sqlite3PagerRefcount(pBt->pPager);
|
|
sCheck.pBt = pBt;
|
|
sCheck.pPager = pBt->pPager;
|
|
sCheck.nPage = btreePagecount(sCheck.pBt);
|
|
sCheck.mxErr = mxErr;
|
|
sCheck.nErr = 0;
|
|
sCheck.mallocFailed = 0;
|
|
*pnErr = 0;
|
|
if( sCheck.nPage==0 ){
|
|
sqlite3BtreeLeave(p);
|
|
return 0;
|
|
}
|
|
sCheck.anRef = sqlite3Malloc( (sCheck.nPage+1)*sizeof(sCheck.anRef[0]) );
|
|
if( !sCheck.anRef ){
|
|
*pnErr = 1;
|
|
sqlite3BtreeLeave(p);
|
|
return 0;
|
|
}
|
|
for(i=0; i<=sCheck.nPage; i++){ sCheck.anRef[i] = 0; }
|
|
i = PENDING_BYTE_PAGE(pBt);
|
|
if( i<=sCheck.nPage ){
|
|
sCheck.anRef[i] = 1;
|
|
}
|
|
sqlite3StrAccumInit(&sCheck.errMsg, zErr, sizeof(zErr), 20000);
|
|
sCheck.errMsg.useMalloc = 2;
|
|
|
|
/* Check the integrity of the freelist
|
|
*/
|
|
checkList(&sCheck, 1, get4byte(&pBt->pPage1->aData[32]),
|
|
get4byte(&pBt->pPage1->aData[36]), "Main freelist: ");
|
|
|
|
/* Check all the tables.
|
|
*/
|
|
for(i=0; (int)i<nRoot && sCheck.mxErr; i++){
|
|
if( aRoot[i]==0 ) continue;
|
|
#ifndef SQLITE_OMIT_AUTOVACUUM
|
|
if( pBt->autoVacuum && aRoot[i]>1 ){
|
|
checkPtrmap(&sCheck, aRoot[i], PTRMAP_ROOTPAGE, 0, 0);
|
|
}
|
|
#endif
|
|
checkTreePage(&sCheck, aRoot[i], "List of tree roots: ", NULL, NULL, verbose, 1, aRoot[i]);
|
|
}
|
|
|
|
/* Check the lazy delete freetable
|
|
*/
|
|
checkLazyDeleteTable(p, &sCheck, aRoot[nRoot-1]);
|
|
|
|
/* Make sure every page in the file is referenced
|
|
*/
|
|
for(i=1; i<=sCheck.nPage && sCheck.mxErr; i++){
|
|
#ifdef SQLITE_OMIT_AUTOVACUUM
|
|
if( sCheck.anRef[i]==0 ){
|
|
checkAppendMsg(&sCheck, 0, "Page %d is never used", i);
|
|
}
|
|
#else
|
|
/* If the database supports auto-vacuum, make sure no tables contain
|
|
** references to pointer-map pages.
|
|
*/
|
|
if( sCheck.anRef[i]==0 &&
|
|
(PTRMAP_PAGENO(pBt, i)!=i || !pBt->autoVacuum) ){
|
|
if (ptrmapGet(pBt, i, &eType, &iPtrPage))
|
|
checkAppendMsg(&sCheck, 0, "Page %d unused, no ptrmap", i);
|
|
else
|
|
checkAppendMsg(&sCheck, 0, "Page %d unused, type %d ptr %d", i, eType, iPtrPage);
|
|
}
|
|
if( sCheck.anRef[i]!=0 &&
|
|
(PTRMAP_PAGENO(pBt, i)==i && pBt->autoVacuum) ){
|
|
checkAppendMsg(&sCheck, 0, "Pointer map page %d is referenced", i);
|
|
}
|
|
#endif
|
|
}
|
|
|
|
/* Make sure this analysis did not leave any unref() pages.
|
|
** This is an internal consistency check; an integrity check
|
|
** of the integrity check.
|
|
*/
|
|
if( NEVER(nRef != sqlite3PagerRefcount(pBt->pPager)) ){
|
|
checkAppendMsg(&sCheck, 0,
|
|
"Outstanding page count goes from %d to %d during this analysis",
|
|
nRef, sqlite3PagerRefcount(pBt->pPager)
|
|
);
|
|
}
|
|
|
|
/* Clean up and report errors.
|
|
*/
|
|
sqlite3BtreeLeave(p);
|
|
sqlite3_free(sCheck.anRef);
|
|
if( sCheck.mallocFailed ){
|
|
sqlite3StrAccumReset(&sCheck.errMsg);
|
|
*pnErr = sCheck.nErr+1;
|
|
return 0;
|
|
}
|
|
*pnErr = sCheck.nErr;
|
|
if( sCheck.nErr==0 ) sqlite3StrAccumReset(&sCheck.errMsg);
|
|
return sqlite3StrAccumFinish(&sCheck.errMsg);
|
|
}
|
|
#endif /* SQLITE_OMIT_INTEGRITY_CHECK */
|
|
|
|
/*
|
|
** Return the full pathname of the underlying database file.
|
|
**
|
|
** The pager filename is invariant as long as the pager is
|
|
** open so it is safe to access without the BtShared mutex.
|
|
*/
|
|
SQLITE_PRIVATE const char *sqlite3BtreeGetFilename(Btree *p){
|
|
assert( p->pBt->pPager!=0 );
|
|
return sqlite3PagerFilename(p->pBt->pPager);
|
|
}
|
|
|
|
/*
|
|
** Return the pathname of the journal file for this database. The return
|
|
** value of this routine is the same regardless of whether the journal file
|
|
** has been created or not.
|
|
**
|
|
** The pager journal filename is invariant as long as the pager is
|
|
** open so it is safe to access without the BtShared mutex.
|
|
*/
|
|
SQLITE_PRIVATE const char *sqlite3BtreeGetJournalname(Btree *p){
|
|
assert( p->pBt->pPager!=0 );
|
|
return sqlite3PagerJournalname(p->pBt->pPager);
|
|
}
|
|
|
|
/*
|
|
** Return non-zero if a transaction is active.
|
|
*/
|
|
SQLITE_PRIVATE int sqlite3BtreeIsInTrans(Btree *p){
|
|
assert( p==0 || sqlite3_mutex_held(p->db->mutex) );
|
|
return (p && (p->inTrans==TRANS_WRITE));
|
|
}
|
|
|
|
#ifndef SQLITE_OMIT_WAL
|
|
/*
|
|
** Run a checkpoint on the Btree passed as the first argument.
|
|
**
|
|
** Return SQLITE_LOCKED if this or any other connection has an open
|
|
** transaction on the shared-cache the argument Btree is connected to.
|
|
**
|
|
** Parameter eMode is one of SQLITE_CHECKPOINT_PASSIVE, FULL or RESTART.
|
|
*/
|
|
SQLITE_PRIVATE int sqlite3BtreeCheckpoint(Btree *p, int eMode, int *pnLog, int *pnCkpt){
|
|
int rc = SQLITE_OK;
|
|
if( p ){
|
|
BtShared *pBt = p->pBt;
|
|
sqlite3BtreeEnter(p);
|
|
if( pBt->inTransaction!=TRANS_NONE ){
|
|
rc = SQLITE_LOCKED;
|
|
}else{
|
|
rc = sqlite3PagerCheckpoint(pBt->pPager, eMode, pnLog, pnCkpt);
|
|
}
|
|
sqlite3BtreeLeave(p);
|
|
}
|
|
return rc;
|
|
}
|
|
#endif
|
|
|
|
/*
|
|
** Return non-zero if a read (or write) transaction is active.
|
|
*/
|
|
SQLITE_PRIVATE int sqlite3BtreeIsInReadTrans(Btree *p){
|
|
assert( p );
|
|
assert( sqlite3_mutex_held(p->db->mutex) );
|
|
return p->inTrans!=TRANS_NONE;
|
|
}
|
|
|
|
SQLITE_PRIVATE int sqlite3BtreeIsInBackup(Btree *p){
|
|
assert( p );
|
|
assert( sqlite3_mutex_held(p->db->mutex) );
|
|
return p->nBackup!=0;
|
|
}
|
|
|
|
/*
|
|
** This function returns a pointer to a blob of memory associated with
|
|
** a single shared-btree. The memory is used by client code for its own
|
|
** purposes (for example, to store a high-level schema associated with
|
|
** the shared-btree). The btree layer manages reference counting issues.
|
|
**
|
|
** The first time this is called on a shared-btree, nBytes bytes of memory
|
|
** are allocated, zeroed, and returned to the caller. For each subsequent
|
|
** call the nBytes parameter is ignored and a pointer to the same blob
|
|
** of memory returned.
|
|
**
|
|
** If the nBytes parameter is 0 and the blob of memory has not yet been
|
|
** allocated, a null pointer is returned. If the blob has already been
|
|
** allocated, it is returned as normal.
|
|
**
|
|
** Just before the shared-btree is closed, the function passed as the
|
|
** xFree argument when the memory allocation was made is invoked on the
|
|
** blob of allocated memory. This function should not call sqlite3_free()
|
|
** on the memory, the btree layer does that.
|
|
*/
|
|
SQLITE_PRIVATE void *sqlite3BtreeSchema(Btree *p, int nBytes, void(*xFree)(void *)){
|
|
BtShared *pBt = p->pBt;
|
|
sqlite3BtreeEnter(p);
|
|
if( !pBt->pSchema && nBytes ){
|
|
pBt->pSchema = sqlite3DbMallocZero(0, nBytes);
|
|
pBt->xFreeSchema = xFree;
|
|
}
|
|
sqlite3BtreeLeave(p);
|
|
return pBt->pSchema;
|
|
}
|
|
|
|
/*
|
|
** Return SQLITE_LOCKED_SHAREDCACHE if another user of the same shared
|
|
** btree as the argument handle holds an exclusive lock on the
|
|
** sqlite_master table. Otherwise SQLITE_OK.
|
|
*/
|
|
SQLITE_PRIVATE int sqlite3BtreeSchemaLocked(Btree *p){
|
|
int rc;
|
|
assert( sqlite3_mutex_held(p->db->mutex) );
|
|
sqlite3BtreeEnter(p);
|
|
rc = querySharedCacheTableLock(p, MASTER_ROOT, READ_LOCK);
|
|
assert( rc==SQLITE_OK || rc==SQLITE_LOCKED_SHAREDCACHE );
|
|
sqlite3BtreeLeave(p);
|
|
return rc;
|
|
}
|
|
|
|
|
|
#ifndef SQLITE_OMIT_SHARED_CACHE
|
|
/*
|
|
** Obtain a lock on the table whose root page is iTab. The
|
|
** lock is a write lock if isWritelock is true or a read lock
|
|
** if it is false.
|
|
*/
|
|
SQLITE_PRIVATE int sqlite3BtreeLockTable(Btree *p, int iTab, u8 isWriteLock){
|
|
int rc = SQLITE_OK;
|
|
assert( p->inTrans!=TRANS_NONE );
|
|
if( p->sharable ){
|
|
u8 lockType = READ_LOCK + isWriteLock;
|
|
assert( READ_LOCK+1==WRITE_LOCK );
|
|
assert( isWriteLock==0 || isWriteLock==1 );
|
|
|
|
sqlite3BtreeEnter(p);
|
|
rc = querySharedCacheTableLock(p, iTab, lockType);
|
|
if( rc==SQLITE_OK ){
|
|
rc = setSharedCacheTableLock(p, iTab, lockType);
|
|
}
|
|
sqlite3BtreeLeave(p);
|
|
}
|
|
return rc;
|
|
}
|
|
#endif
|
|
|
|
#ifndef SQLITE_OMIT_INCRBLOB
|
|
/*
|
|
** Argument pCsr must be a cursor opened for writing on an
|
|
** INTKEY table currently pointing at a valid table entry.
|
|
** This function modifies the data stored as part of that entry.
|
|
**
|
|
** Only the data content may only be modified, it is not possible to
|
|
** change the length of the data stored. If this function is called with
|
|
** parameters that attempt to write past the end of the existing data,
|
|
** no modifications are made and SQLITE_CORRUPT is returned.
|
|
*/
|
|
SQLITE_PRIVATE int sqlite3BtreePutData(BtCursor *pCsr, u32 offset, u32 amt, void *z){
|
|
int rc;
|
|
assert( cursorHoldsMutex(pCsr) );
|
|
assert( sqlite3_mutex_held(pCsr->pBtree->db->mutex) );
|
|
assert( pCsr->isIncrblobHandle );
|
|
|
|
rc = restoreCursorPosition(pCsr);
|
|
if( rc!=SQLITE_OK ){
|
|
return rc;
|
|
}
|
|
assert( pCsr->eState!=CURSOR_REQUIRESEEK );
|
|
if( pCsr->eState!=CURSOR_VALID ){
|
|
return SQLITE_ABORT;
|
|
}
|
|
|
|
/* Check some assumptions:
|
|
** (a) the cursor is open for writing,
|
|
** (b) there is a read/write transaction open,
|
|
** (c) the connection holds a write-lock on the table (if required),
|
|
** (d) there are no conflicting read-locks, and
|
|
** (e) the cursor points at a valid row of an intKey table.
|
|
*/
|
|
if( !pCsr->wrFlag ){
|
|
return SQLITE_READONLY;
|
|
}
|
|
assert( !pCsr->pBt->readOnly && pCsr->pBt->inTransaction==TRANS_WRITE );
|
|
assert( hasSharedCacheTableLock(pCsr->pBtree, pCsr->pgnoRoot, 0, 2) );
|
|
assert( !hasReadConflicts(pCsr->pBtree, pCsr->pgnoRoot) );
|
|
assert( pCsr->apPage[pCsr->iPage]->intKey );
|
|
|
|
return accessPayload(pCsr, offset, amt, (unsigned char *)z, 1);
|
|
}
|
|
|
|
/*
|
|
** Set a flag on this cursor to cache the locations of pages from the
|
|
** overflow list for the current row. This is used by cursors opened
|
|
** for incremental blob IO only.
|
|
**
|
|
** This function sets a flag only. The actual page location cache
|
|
** (stored in BtCursor.aOverflow[]) is allocated and used by function
|
|
** accessPayload() (the worker function for sqlite3BtreeData() and
|
|
** sqlite3BtreePutData()).
|
|
*/
|
|
SQLITE_PRIVATE void sqlite3BtreeCacheOverflow(BtCursor *pCur){
|
|
assert( cursorHoldsMutex(pCur) );
|
|
assert( sqlite3_mutex_held(pCur->pBtree->db->mutex) );
|
|
invalidateOverflowCache(pCur);
|
|
pCur->isIncrblobHandle = 1;
|
|
}
|
|
#endif
|
|
|
|
/*
|
|
** Set both the "read version" (single byte at byte offset 18) and
|
|
** "write version" (single byte at byte offset 19) fields in the database
|
|
** header to iVersion.
|
|
*/
|
|
SQLITE_PRIVATE int sqlite3BtreeSetVersion(Btree *pBtree, int iVersion){
|
|
BtShared *pBt = pBtree->pBt;
|
|
int rc; /* Return code */
|
|
|
|
assert( pBtree->inTrans==TRANS_NONE );
|
|
assert( iVersion==1 || iVersion==2 );
|
|
|
|
/* If setting the version fields to 1, do not automatically open the
|
|
** WAL connection, even if the version fields are currently set to 2.
|
|
*/
|
|
pBt->doNotUseWAL = (u8)(iVersion==1);
|
|
|
|
rc = sqlite3BtreeBeginTrans(pBtree, 0);
|
|
if( rc==SQLITE_OK ){
|
|
u8 *aData = pBt->pPage1->aData;
|
|
if( aData[18]!=(u8)iVersion || aData[19]!=(u8)iVersion ){
|
|
rc = sqlite3BtreeBeginTrans(pBtree, 2);
|
|
if( rc==SQLITE_OK ){
|
|
rc = sqlite3PagerWrite(pBt->pPage1->pDbPage);
|
|
if( rc==SQLITE_OK ){
|
|
aData[18] = (u8)iVersion;
|
|
aData[19] = (u8)iVersion;
|
|
}
|
|
}
|
|
}
|
|
}
|
|
|
|
pBt->doNotUseWAL = 0;
|
|
return rc;
|
|
}
|
|
|
|
/************** End of btree.c ***********************************************/
|