foundationdb/fdbserver/KeyValueStoreSQLite.actor.cpp

2275 lines
81 KiB
C++

/*
* KeyValueStoreSQLite.actor.cpp
*
* This source file is part of the FoundationDB open source project
*
* Copyright 2013-2018 Apple Inc. and the FoundationDB project authors
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
#define SQLITE_THREADSAFE 0 // also in sqlite3.amalgamation.c!
#include "flow/crc32c.h"
#include "fdbserver/IKeyValueStore.h"
#include "fdbserver/CoroFlow.h"
#include "fdbserver/Knobs.h"
#include "flow/Hash3.h"
#include "flow/xxhash.h"
extern "C" {
#include "fdbserver/sqlite/sqliteInt.h"
u32 sqlite3VdbeSerialGet(const unsigned char*, u32, Mem*);
}
#include "flow/ThreadPrimitives.h"
#include "fdbserver/VFSAsync.h"
#include "fdbserver/template_fdb.h"
#include "fdbrpc/simulator.h"
#include "flow/actorcompiler.h" // This must be the last #include.
#if SQLITE_THREADSAFE == 0
#define sqlite3_mutex_enter(x)
#define sqlite3_mutex_leave(x)
#endif
void hexdump(FILE* fout, StringRef val);
/*#undef state
#include <Windows.h>*/
/*uint64_t getFileSize( const char* filename ) {
HANDLE f = CreateFile( filename, GENERIC_READ, FILE_SHARE_READ|FILE_SHARE_WRITE|FILE_SHARE_DELETE, nullptr,
OPEN_EXISTING, 0, nullptr); if (f == INVALID_HANDLE_VALUE) return 0; DWORD hi,lo; lo = GetFileSize(f, &hi);
CloseHandle(f);
return (uint64_t(hi)<<32) + lo;
}*/
struct SpringCleaningStats {
int64_t springCleaningCount;
int64_t lazyDeletePages;
int64_t vacuumedPages;
double springCleaningTime;
double vacuumTime;
double lazyDeleteTime;
SpringCleaningStats()
: springCleaningCount(0), lazyDeletePages(0), vacuumedPages(0), springCleaningTime(0.0), vacuumTime(0.0),
lazyDeleteTime(0.0) {}
};
struct PageChecksumCodec {
PageChecksumCodec(std::string const& filename) : pageSize(0), reserveSize(0), filename(filename), silent(false) {}
int pageSize;
int reserveSize;
std::string filename;
bool silent;
struct SumType {
bool operator==(const SumType& rhs) const { return part1 == rhs.part1 && part2 == rhs.part2; }
uint32_t part1;
uint32_t part2;
std::string toString() { return format("0x%08x%08x", part1, part2); }
};
// Calculates and then either stores or verifies a checksum.
// The checksum is read/stored at the end of the page buffer.
// Page size is passed in as pageLen because this->pageSize is not always appropriate.
// If write is true then the checksum is written into the page and true is returned.
// If write is false then the checksum is compared to the in-page sum and the return value
// is whether or not the checksums were equal.
bool checksum(Pgno pageNumber, void* data, int pageLen, bool write) {
ASSERT(pageLen > sizeof(SumType));
char* pData = (char*)data;
int dataLen = pageLen - sizeof(SumType);
SumType* pSumInPage = (SumType*)(pData + dataLen);
if (write) {
// Always write a xxHash3 checksum for new pages
// First 8 bits are set to 0 so that with high probability,
// checksums written with hashlittle2 don't require calculating
// an xxHash3 checksum on read
auto xxHash3 = XXH3_64bits(data, dataLen);
pSumInPage->part1 = static_cast<uint32_t>((xxHash3 >> 32) & 0x00ffffff);
pSumInPage->part2 = static_cast<uint32_t>(xxHash3 & 0xffffffff);
return true;
}
SumType crc32Sum;
if (pSumInPage->part1 == 0) {
// part1 being 0 indicates with very high probability that a CRC32 checksum
// was used, so check that first. If this checksum fails, there is still
// some chance the page was written with another checksum algorithm
crc32Sum.part1 = 0;
crc32Sum.part2 = crc32c_append(0xfdbeefdb, static_cast<uint8_t*>(data), dataLen);
if (crc32Sum == *pSumInPage) {
TEST(true); // Read CRC32 checksum
return true;
}
}
// Try xxhash3
SumType xxHash3Sum;
if ((pSumInPage->part1 >> 24) == 0) {
// The first 8 bits of part1 being 0 indicates with high probability that an
// xxHash3 checksum was used, so check that next. If this checksum fails, there is
// still some chance the page was written with hashlittle2, so fall back to checking
// hashlittle2
auto xxHash3 = XXH3_64bits(data, dataLen);
xxHash3Sum.part1 = static_cast<uint32_t>((xxHash3 >> 32) & 0x00ffffff);
xxHash3Sum.part2 = static_cast<uint32_t>(xxHash3 & 0xffffffff);
if (xxHash3Sum == *pSumInPage) {
TEST(true); // Read xxHash3 checksum
return true;
}
}
// Try hashlittle2
SumType hashLittle2Sum;
hashLittle2Sum.part1 = pageNumber; // DO NOT CHANGE
hashLittle2Sum.part2 = 0x5ca1ab1e;
hashlittle2(pData, dataLen, &hashLittle2Sum.part1, &hashLittle2Sum.part2);
if (hashLittle2Sum == *pSumInPage) {
TEST(true); // Read HashLittle2 checksum
return true;
}
if (!silent) {
TraceEvent trEvent(SevError, "SQLitePageChecksumFailure");
trEvent.error(checksum_failed())
.detail("CodecPageSize", pageSize)
.detail("CodecReserveSize", reserveSize)
.detail("Filename", filename)
.detail("PageNumber", pageNumber)
.detail("PageSize", pageLen)
.detail("ChecksumInPage", pSumInPage->toString())
.detail("ChecksumCalculatedHL2", hashLittle2Sum.toString());
if (pSumInPage->part1 == 0) {
trEvent.detail("ChecksumCalculatedCRC", crc32Sum.toString());
}
if (pSumInPage->part1 >> 24 == 0) {
trEvent.detail("ChecksumCalculatedXXHash3", xxHash3Sum.toString());
}
}
return false;
}
static void* codec(void* vpSelf, void* data, Pgno pageNumber, int op) {
PageChecksumCodec* self = (PageChecksumCodec*)vpSelf;
// Page write operations are 6 for DB page and 7 for journal page
bool write = (op == 6 || op == 7);
// Page read is operation 3, which must be the operation if it's not a write.
ASSERT(write || op == 3);
// Page 1 is special. It contains the database configuration including Page Size and Reserve Size.
// SQLite can't get authoritative values for these things until the Pager Codec has validated (and
// potentially decrypted) Page 1 itself, so it can't tell the Pager Codec what those things are before
// Page 1 is handled. It will guess a Page Size of SQLITE_DEFAULT_PAGE_SIZE, and a Reserve Size based
// on the pre-verified (and perhaps still encrypted) header in the Page 1 data that it will then pass
// to the Pager Codec.
//
// So, Page 1 must be written and verifiable as a SQLITE_DEFAULT_PAGE_SIZE sized page as well as
// the actual configured page size for the database, if it is larger. A configured page size lower
// than the default (in other words 512) results in undefined behavior.
if (pageNumber == 1) {
if (write && self->pageSize > SQLITE_DEFAULT_PAGE_SIZE) {
self->checksum(pageNumber, data, SQLITE_DEFAULT_PAGE_SIZE, write);
}
} else {
// For Page Numbers other than 1, reserve size must be the size of the checksum.
if (self->reserveSize != sizeof(SumType)) {
if (!self->silent)
TraceEvent(SevWarnAlways, "SQLitePageChecksumFailureBadReserveSize")
.detail("CodecPageSize", self->pageSize)
.detail("CodecReserveSize", self->reserveSize)
.detail("Filename", self->filename)
.detail("PageNumber", pageNumber);
return nullptr;
}
}
if (!self->checksum(pageNumber, data, self->pageSize, write))
return nullptr;
return data;
}
static void sizeChange(void* vpSelf, int new_pageSize, int new_reserveSize) {
PageChecksumCodec* self = (PageChecksumCodec*)vpSelf;
self->pageSize = new_pageSize;
self->reserveSize = new_reserveSize;
}
static void free(void* vpSelf) {
PageChecksumCodec* self = (PageChecksumCodec*)vpSelf;
delete self;
}
};
struct SQLiteDB : NonCopyable {
std::string filename;
sqlite3* db;
Btree* btree;
int table, freetable;
bool haveMutex;
Reference<IAsyncFile> dbFile, walFile;
bool page_checksums;
bool fragment_values;
PageChecksumCodec* pPagerCodec; // we do NOT own this pointer, db does.
void beginTransaction(bool write) { checkError("BtreeBeginTrans", sqlite3BtreeBeginTrans(btree, write)); }
void endTransaction() { checkError("BtreeCommit", sqlite3BtreeCommit(btree)); }
void rollback() { checkError("BtreeRollback", sqlite3BtreeRollback(btree)); }
void open(bool writable);
void createFromScratch();
SQLiteDB(std::string filename, bool page_checksums, bool fragment_values)
: filename(filename), db(nullptr), btree(nullptr), table(-1), freetable(-1), haveMutex(false),
page_checksums(page_checksums), fragment_values(fragment_values) {
TraceEvent(SevDebug, "SQLiteDBCreate").detail("This", (void*)this).detail("Filename", filename).backtrace();
}
~SQLiteDB() {
TraceEvent(SevDebug, "SQLiteDBDestroy").detail("This", (void*)this).detail("Filename", filename).backtrace();
if (db) {
if (haveMutex) {
sqlite3_mutex_leave(db->mutex);
}
sqlite3_close(db);
}
}
void initPagerCodec() {
if (page_checksums) {
int r = sqlite3_test_control(SQLITE_TESTCTRL_RESERVE, db, sizeof(PageChecksumCodec::SumType));
if (r != 0) {
TraceEvent(SevError, "BtreePageReserveSizeSetError")
.detail("Filename", filename)
.detail("ErrorCode", r);
ASSERT(false);
}
// Always start with a new pager codec with default options.
pPagerCodec = new PageChecksumCodec(filename);
sqlite3BtreePagerSetCodec(
btree, PageChecksumCodec::codec, PageChecksumCodec::sizeChange, PageChecksumCodec::free, pPagerCodec);
}
}
void checkError(const char* context, int rc) {
// if (deterministicRandom()->random01() < .001) rc = SQLITE_INTERRUPT;
if (rc) {
// Our exceptions don't propagate through sqlite, so we don't know for sure if the error that caused this
// was an injected fault. Assume that if VFSAsyncFile caught an injected Error that it caused this error
// return code.
Error err = io_error();
if (g_network->isSimulated() && VFSAsyncFile::checkInjectedError()) {
err = err.asInjectedFault();
}
if (db)
db->errCode = rc;
if (rc == SQLITE_NOMEM)
platform::outOfMemory(); // SOMEDAY: Trap out of memory errors at allocation time; check out different
// allocation options in sqlite
TraceEvent(SevError, "DiskError")
.error(err)
.detail("In", context)
.detail("File", filename)
.detail("SQLiteError", sqlite3ErrStr(rc))
.detail("SQLiteErrorCode", rc)
.GetLastError();
throw err;
}
}
void checkpoint(bool restart) {
int logSize = 0, checkpointCount = 0;
// double t = timer();
while (true) {
int rc = sqlite3_wal_checkpoint_v2(
db, 0, restart ? SQLITE_CHECKPOINT_RESTART : SQLITE_CHECKPOINT_FULL, &logSize, &checkpointCount);
if (!rc)
break;
if ((sqlite3_errcode(db) & 0xff) == SQLITE_BUSY) {
// printf("#");
// threadSleep(.010);
sqlite3_sleep(10);
} else
checkError("checkpoint", rc);
}
// printf("Checkpoint (%0.1f ms): %d frames in log, %d checkpointed\n", (timer()-t)*1000, logSize,
// checkpointCount);
}
uint32_t freePages() {
u32 fp = 0;
sqlite3BtreeGetMeta(btree, BTREE_FREE_PAGE_COUNT, &fp);
return fp;
}
bool vacuum() { // Returns true if vacuum is complete or stalled by a lazy free root
int rc = sqlite3BtreeIncrVacuum(btree);
if (rc && rc != SQLITE_DONE)
checkError("vacuum", rc);
return rc == SQLITE_DONE;
}
int check(bool verbose) {
int errors = 0;
int tables[] = { 1, table, freetable };
TraceEvent("BTreeIntegrityCheckBegin").detail("Filename", filename);
char* e = sqlite3BtreeIntegrityCheck(btree, tables, 3, 1000, &errors, verbose);
if (!(g_network->isSimulated() && VFSAsyncFile::checkInjectedError())) {
TraceEvent((errors || e) ? SevError : SevInfo, "BTreeIntegrityCheckResults")
.detail("Filename", filename)
.detail("ErrorTotal", errors);
if (e != nullptr) {
// e is a string containing 1 or more lines. Create a separate trace event for each line.
char* lineStart = e;
while (lineStart != nullptr) {
char* lineEnd = strstr(lineStart, "\n");
if (lineEnd != nullptr) {
*lineEnd = '\0';
++lineEnd;
}
// If the line length found is not zero then print a trace event
if (*lineStart != '\0')
TraceEvent(SevError, "BTreeIntegrityCheck")
.detail("Filename", filename)
.detail("ErrorDetail", lineStart);
lineStart = lineEnd;
}
}
TEST(true); // BTree integrity checked
}
if (e)
sqlite3_free(e);
return errors;
}
int checkAllPageChecksums();
};
class Statement : NonCopyable {
SQLiteDB& db;
sqlite3_stmt* stmt;
public:
Statement(SQLiteDB& db, const char* sql) : db(db), stmt(nullptr) {
db.checkError("prepare", sqlite3_prepare_v2(db.db, sql, -1, &stmt, nullptr));
}
~Statement() {
try {
db.checkError("finalize", sqlite3_finalize(stmt));
} catch (...) {
}
}
Statement& reset() {
db.checkError("reset", sqlite3_reset(stmt));
return *this;
}
Statement& param(int i, StringRef value) {
db.checkError("bind", sqlite3_bind_blob(stmt, i, value.begin(), value.size(), SQLITE_STATIC));
return *this;
}
Statement& param(int i, int value) {
db.checkError("bind", sqlite3_bind_int(stmt, i, value));
return *this;
}
Statement& execute() {
int r = sqlite3_step(stmt);
if (r == SQLITE_ROW)
db.checkError("execute called on statement that returns rows", r);
if (r != SQLITE_DONE)
db.checkError("execute", r);
return *this;
}
bool nextRow() {
int r = sqlite3_step(stmt);
if (r == SQLITE_ROW)
return true;
if (r == SQLITE_DONE)
return false;
db.checkError("nextRow", r);
__assume(false); // NOT REACHED
}
StringRef column(int i) {
return StringRef((const uint8_t*)sqlite3_column_blob(stmt, i), sqlite3_column_bytes(stmt, i));
}
};
void hexdump(FILE* fout, StringRef val) {
int buflen = val.size();
const unsigned char* buf = val.begin();
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");
}
}
Value encode(KeyValueRef kv) {
int keyCode = kv.key.size() * 2 + 12;
int valCode = kv.value.size() * 2 + 12;
int header_size = sqlite3VarintLen(keyCode) + sqlite3VarintLen(valCode);
int hh = sqlite3VarintLen(header_size);
header_size += hh;
if (hh < sqlite3VarintLen(header_size))
header_size++;
int size = header_size + kv.key.size() + kv.value.size();
Value v;
uint8_t* d = new (v.arena()) uint8_t[size];
((ValueRef&)v) = KeyRef(d, size);
d += sqlite3PutVarint(d, header_size);
d += sqlite3PutVarint(d, keyCode);
d += sqlite3PutVarint(d, valCode);
memcpy(d, kv.key.begin(), kv.key.size());
d += kv.key.size();
memcpy(d, kv.value.begin(), kv.value.size());
d += kv.value.size();
ASSERT(d == v.begin() + size);
return v;
}
// Fragments are encoded as (key, index, value) tuples
// An index of 0 indicates an unfragmented KV pair.
// For fragmented KV pairs, the values will be concatenated in index order.
//
// In the current implementation, index values are chosen to enable a single linear
// pass over the fragments, in forward or backward order, to immediately know the final
// unfragmented value size accurately enough to allocate a buffer that is certainly large
// enough to hold the defragmented bytes.
//
// However, the decoder could be made to work if these index value 'hints' become inaccurate
// due to a change in splitting logic or index numbering. The decoder would just have to support
// buffer expansion as needed.
//
// Note that changing the following value constitutes a change in index numbering.
#define KV_FRAGMENT_INDEX_SIZE_HINT_FACTOR 4
Value encodeKVFragment(KeyValueRef kv, uint32_t index) {
int keyCode = kv.key.size() * 2 + 12;
int valCode = kv.value.size() * 2 + 12;
// The SQLite type code for the index is the minimal number of bytes needed to store
// a signed representation of the index value. The type code for 0 is 0 (which is
// actually the null type in SQLite).
int8_t indexCode = 0;
if (index != 0) {
uint32_t tmp = index;
while (tmp != 0) {
++indexCode;
tmp >>= 8;
}
// An increment is required if the high bit of the N-byte index value is set, since it is
// positive number but SQLite only stores signed values and would interpret it as negative.
if (index >> (8 * indexCode - 1))
++indexCode;
}
int header_size = sqlite3VarintLen(keyCode) + sizeof(indexCode) + sqlite3VarintLen(valCode);
int hh = sqlite3VarintLen(header_size);
header_size += hh;
if (hh < sqlite3VarintLen(header_size))
header_size++;
int size = header_size + kv.key.size() + indexCode + kv.value.size();
Value v;
uint8_t* d = new (v.arena()) uint8_t[size];
((ValueRef&)v) = KeyRef(d, size);
d += sqlite3PutVarint(d, header_size);
d += sqlite3PutVarint(d, keyCode);
*d++ = indexCode;
d += sqlite3PutVarint(d, valCode);
// Write key
memcpy(d, kv.key.begin(), kv.key.size());
d += kv.key.size();
// Write index bytes, if any
for (int i = indexCode - 1; i >= 0; --i) {
d[i] = (uint8_t)index;
index >>= 8;
}
d += indexCode;
// Write value
memcpy(d, kv.value.begin(), kv.value.size());
d += kv.value.size();
ASSERT(d == v.begin() + size);
return v;
}
int getEncodedSize(int keySize, int valuePrefixSize) {
int keyCode = keySize * 2 + 12;
int header_size =
sqlite3VarintLen(keyCode) + 8; // 8 is the maximum return value of sqlite3VarintLen(), so this is our worst case
// header size (for values larger than allowable database values)
int hh = sqlite3VarintLen(header_size);
header_size += hh;
if (hh < sqlite3VarintLen(header_size))
header_size++;
return header_size + keySize + valuePrefixSize;
}
KeyValueRef decodeKV(StringRef encoded) {
uint8_t const* d = encoded.begin();
uint64_t h, len1, len2;
d += sqlite3GetVarint(d, (u64*)&h);
d += sqlite3GetVarint(d, (u64*)&len1);
d += sqlite3GetVarint(d, (u64*)&len2);
ASSERT(d == encoded.begin() + h);
ASSERT(len1 >= 12 && !(len1 & 1));
ASSERT(len2 >= 12 && !(len2 & 1));
len1 = (len1 - 12) / 2;
len2 = (len2 - 12) / 2;
ASSERT(d + len1 + len2 == encoded.end());
return KeyValueRef(KeyRef(d, len1), KeyRef(d + len1, len2));
}
// Given a key size and value prefix size, get the minimum bytes that must be read from the underlying
// btree tuple to safely read the prefix length from the value bytes (if the value is long enough)
int getEncodedKVFragmentSize(int keySize, int valuePrefixSize) {
int keyCode = keySize * 2 + 12;
int header_size = sqlite3VarintLen(keyCode) + 1 // index code length
+ 8; // worst case for value size (larger than fdb api allows)
int hh = sqlite3VarintLen(header_size);
header_size += hh;
if (hh < sqlite3VarintLen(header_size))
header_size++;
return header_size + keySize + 4 // Max width allowed of index value
+ valuePrefixSize;
}
// Decode (key, index, value) tuple.
// A present() Optional will always be returned UNLESS partial is true.
// If partial is true then the return will not be present() unless at least
// the full key and index were in the encoded buffer. The value returned will be 0 or
// more value bytes, however many were available.
// Note that a short encoded buffer must at *least* contain the header length varint.
Optional<KeyValueRef> decodeKVFragment(StringRef encoded, uint32_t* index = nullptr, bool partial = false) {
uint8_t const* d = encoded.begin();
uint64_t h, len1, len2;
d += sqlite3GetVarint(d, (u64*)&h);
// Make sure entire header is present, else return nothing
if (partial && encoded.size() < h)
return Optional<KeyValueRef>();
d += sqlite3GetVarint(d, (u64*)&len1);
const uint8_t indexLen = *d++;
ASSERT(indexLen <= 4);
d += sqlite3GetVarint(d, (u64*)&len2);
ASSERT(d == encoded.begin() + h);
ASSERT(len1 >= 12 && !(len1 & 1));
ASSERT(len2 >= 12 && !(len2 & 1));
len1 = (len1 - 12) / 2;
len2 = (len2 - 12) / 2;
if (partial) {
// If the key and index aren't complete, return nothing.
if (d + len1 + indexLen > encoded.end())
return Optional<KeyValueRef>();
// Encoded size shouldn't be *larger* than the record described by the header no matter what.
ASSERT(d + len1 + indexLen + len2 >= encoded.end());
// Shorten value length to be whatever bytes remain after the header/key/index
len2 = std::min(len2, (uint64_t)(encoded.end() - indexLen - len1 - d));
} else {
// But for non partial records encoded size should be exactly the size of the described record.
ASSERT(d + len1 + indexLen + len2 == encoded.end());
}
// Decode big endian index
if (index != nullptr) {
if (indexLen == 0)
*index = 0;
else {
const uint8_t* begin = d + len1;
const uint8_t* end = begin + indexLen;
*index = (uint8_t)*begin++;
while (begin < end) {
*index <<= 8;
*index |= *begin++;
}
}
}
return KeyValueRef(KeyRef(d, len1), KeyRef(d + len1 + indexLen, len2));
}
KeyValueRef decodeKVPrefix(StringRef encoded, int maxLength) {
uint8_t const* d = encoded.begin();
uint64_t h, len1, len2;
d += sqlite3GetVarint(d, (u64*)&h);
d += sqlite3GetVarint(d, (u64*)&len1);
d += sqlite3GetVarint(d, (u64*)&len2);
ASSERT(d == encoded.begin() + h);
ASSERT(len1 >= 12 && !(len1 & 1));
ASSERT(len2 >= 12 && !(len2 & 1));
len1 = (len1 - 12) / 2;
len2 = (len2 - 12) / 2;
len2 = std::min(len2, (uint64_t)maxLength);
ASSERT(d + len1 + len2 <= encoded.end());
return KeyValueRef(KeyRef(d, len1), KeyRef(d + len1, len2));
}
Value encodeKey(KeyRef key, bool using_fragments) {
int keyCode = key.size() * 2 + 12;
int header_size = sqlite3VarintLen(keyCode);
if (using_fragments) // will be encoded as key, 0 (where 0 is really a null)
++header_size;
int hh = sqlite3VarintLen(header_size);
header_size += hh;
if (hh < sqlite3VarintLen(header_size))
header_size++;
int size = header_size + key.size();
Value v;
uint8_t* d = new (v.arena()) uint8_t[size];
((ValueRef&)v) = KeyRef(d, size);
d += sqlite3PutVarint(d, header_size);
d += sqlite3PutVarint(d, keyCode);
if (using_fragments)
*d++ = 0;
memcpy(d, key.begin(), key.size());
d += key.size();
ASSERT(d == v.begin() + size);
return v;
}
struct SQLiteTransaction {
SQLiteDB& db;
bool shouldCommit;
SQLiteTransaction(SQLiteDB& db, bool write) : db(db), shouldCommit(false) { db.beginTransaction(write); }
void commit() { shouldCommit = true; }
~SQLiteTransaction() {
try {
if (shouldCommit)
db.endTransaction();
else
db.rollback();
} catch (...) {
}
}
};
struct IntKeyCursor {
SQLiteDB& db;
BtCursor* cursor;
IntKeyCursor(SQLiteDB& db, int table, bool write) : db(db), cursor(nullptr) {
cursor = (BtCursor*)new char[sqlite3BtreeCursorSize()];
sqlite3BtreeCursorZero(cursor);
db.checkError("BtreeCursor", sqlite3BtreeCursor(db.btree, table, write, nullptr, cursor));
}
~IntKeyCursor() {
if (cursor) {
try {
db.checkError("BtreeCloseCursor", sqlite3BtreeCloseCursor(cursor));
} catch (...) {
}
delete[](char*) cursor;
}
}
};
struct RawCursor {
SQLiteDB& db;
BtCursor* cursor;
KeyInfo keyInfo;
bool valid;
operator bool() const { return valid; }
RawCursor(SQLiteDB& db, int table, bool write) : db(db), cursor(nullptr), valid(false) {
keyInfo.db = db.db;
keyInfo.enc = db.db->aDb[0].pSchema->enc;
keyInfo.aColl[0] = db.db->pDfltColl;
keyInfo.aSortOrder = 0;
keyInfo.nField = 1;
try {
cursor = (BtCursor*)new char[sqlite3BtreeCursorSize()];
sqlite3BtreeCursorZero(cursor);
db.checkError("BtreeCursor", sqlite3BtreeCursor(db.btree, table, write, &keyInfo, cursor));
} catch (...) {
destroyCursor();
throw;
}
}
~RawCursor() { destroyCursor(); }
void destroyCursor() {
if (cursor) {
try {
db.checkError("BtreeCloseCursor", sqlite3BtreeCloseCursor(cursor));
} catch (...) {
TraceEvent(SevError, "RawCursorDestructionError").log();
}
delete[](char*) cursor;
}
}
void moveFirst() {
int empty = 1;
db.checkError("BtreeFirst", sqlite3BtreeFirst(cursor, &empty));
valid = !empty;
}
void moveNext() {
int empty = 1;
db.checkError("BtreeNext", sqlite3BtreeNext(cursor, &empty));
valid = !empty;
}
void movePrevious() {
int empty = 1;
db.checkError("BtreePrevious", sqlite3BtreePrevious(cursor, &empty));
valid = !empty;
}
int size() {
int64_t size;
db.checkError("BtreeKeySize", sqlite3BtreeKeySize(cursor, (i64*)&size));
ASSERT(size < (1 << 30));
return size;
}
Value getEncodedRow() {
int s = size();
Value v;
uint8_t* d = new (v.arena()) uint8_t[s];
db.checkError("BtreeKey", sqlite3BtreeKey(cursor, 0, s, d));
((ValueRef&)v) = KeyRef(d, s);
return v;
}
ValueRef getEncodedRow(Arena& arena) {
int s = size();
uint8_t* d = new (arena) uint8_t[s];
db.checkError("BtreeKey", sqlite3BtreeKey(cursor, 0, s, d));
return KeyRef(d, s);
}
ValueRef getEncodedRowPrefix(Arena& arena, int maxEncodedSize) {
int s = std::min(size(), maxEncodedSize);
uint8_t* d = new (arena) uint8_t[s];
db.checkError("BtreeKey", sqlite3BtreeKey(cursor, 0, s, d));
return KeyRef(d, s);
}
void insertFragment(KeyValueRef kv, uint32_t index, int seekResult) {
Value v = encodeKVFragment(kv, index);
db.checkError("BtreeInsert", sqlite3BtreeInsert(cursor, v.begin(), v.size(), nullptr, 0, 0, 0, seekResult));
}
void remove() { db.checkError("BtreeDelete", sqlite3BtreeDelete(cursor)); }
void set(KeyValueRef kv) {
if (db.fragment_values) {
// Unlike a read, where we need to access fragments in fully forward or reverse order,
// here we just want to delete any existing fragments for the key. It does not matter
// what order we delete them in, and SQLite requires us to seek after every delete, so
// the fastest way to do this is to repeatedly seek to the tuple prefix (key, ) and
// delete the current fragment until nothing is there.
// This should result in almost identical performance to non-fragmenting mode for single fragment kv pairs.
int seekResult = moveTo(kv.key, true); // second arg means to ignore fragmenting and seek to (key, )
while (seekResult == 0) {
remove();
seekResult = moveTo(kv.key, true);
}
const int primaryPageUsable = SERVER_KNOBS->SQLITE_FRAGMENT_PRIMARY_PAGE_USABLE;
const int overflowPageUsable = SERVER_KNOBS->SQLITE_FRAGMENT_OVERFLOW_PAGE_USABLE;
int fragments = 1;
int valuePerFragment = kv.value.size();
// Figure out if we would benefit from fragmenting this kv pair. The key size must be less than
// primary page usable size, and the value and key size together must exceeed the primary page usable size.
if ((kv.key.size() + kv.value.size()) > primaryPageUsable && kv.key.size() < primaryPageUsable) {
// Just the part of the value that would be in a partially-filled overflow page
int overflowPartialBytes = (kv.expectedSize() - primaryPageUsable) % overflowPageUsable;
// Number of bytes wasted in the unfragmented case
int unfragmentedWaste = overflowPageUsable - overflowPartialBytes;
// Total space used for unfragmented form
int unfragmentedTotal = kv.expectedSize() + unfragmentedWaste;
// Value bytes that can fit in the primary page for each fragment
int primaryPageValueBytes = primaryPageUsable - kv.key.size();
// Calculate how many total fragments it would take to spread the partial overflow page bytes and the
// first fragment's primary page value bytes evenly over multiple tuples that fit in primary pages.
fragments =
(primaryPageValueBytes + overflowPartialBytes + primaryPageValueBytes - 1) / primaryPageValueBytes;
// Number of bytes wasted in the fragmented case (for the extra key copies)
int fragmentedWaste = kv.key.size() * (fragments - 1);
// Total bytes used for the fragmented case
// int fragmentedTotal = kv.expectedSize() + fragmentedWaste;
// Calculate bytes saved by having extra key instances stored vs the original partial overflow page
// bytes.
int savings = unfragmentedWaste - fragmentedWaste;
double reduction = (double)savings / unfragmentedTotal;
// printf("K: %5d V: %6d OVERFLOW: %5d FRAGMENTS: %3d SAVINGS: %4d FRAG: %7d UNFRAG: %7d
// REDUCTION: %.3f\n", kv.key.size(), kv.value.size(), overflowPartialBytes, fragments, savings,
// fragmentedTotal, unfragmentedTotal, reduction);
if (reduction < SERVER_KNOBS->SQLITE_FRAGMENT_MIN_SAVINGS)
fragments = 1;
else
valuePerFragment = (primaryPageValueBytes + overflowPartialBytes + fragments - 1) / fragments;
}
if (fragments == 1) {
insertFragment(kv, 0, seekResult);
return;
}
// First index is ceiling(value_size / KV_FRAGMENT_INDEX_SIZE_HINT_FACTOR)
uint32_t nextIndex =
(kv.value.size() + KV_FRAGMENT_INDEX_SIZE_HINT_FACTOR - 1) / KV_FRAGMENT_INDEX_SIZE_HINT_FACTOR;
// Last index is ceiling(value_size / (KV_FRAGMENT_INDEX_SIZE_HINT_FACTOR / 2) )
uint32_t finalIndex = (kv.value.size() + (KV_FRAGMENT_INDEX_SIZE_HINT_FACTOR / 2) - 1) /
(KV_FRAGMENT_INDEX_SIZE_HINT_FACTOR / 2);
int bytesLeft = kv.value.size();
int readPos = 0;
while (bytesLeft > 0) {
--fragments; // remaining ideal fragment count
int fragSize = (fragments == 0) ? bytesLeft : std::min<int>(bytesLeft, valuePerFragment);
// The last fragment must have an index of finalIndex or higher.
if (fragSize == bytesLeft && nextIndex < finalIndex)
nextIndex = finalIndex;
// printf("insert ks %d vs %d fragment %d, %dbytes\n", kv.key.size(), kv.value.size(), nextIndex,
// fragSize);
insertFragment(KeyValueRef(kv.key, kv.value.substr(readPos, fragSize)), nextIndex, seekResult);
// seekResult can only be used for the first insertion.
if (seekResult != 0)
seekResult = 0;
readPos += fragSize;
bytesLeft -= fragSize;
++nextIndex;
}
} else {
int r = moveTo(kv.key);
if (!r)
remove();
Value v = encode(kv);
db.checkError("BTreeInsert", sqlite3BtreeInsert(cursor, v.begin(), v.size(), nullptr, 0, 0, 0, r));
}
}
void clearOne(KeyRangeRef keys) {
ASSERT(!db.fragment_values);
int r = moveTo(keys.begin);
if (r < 0)
moveNext();
ASSERT(valid && decodeKV(getEncodedRow()).key < keys.end);
remove();
}
void clear(KeyRangeRef keys) {
// TODO: This is really slow!
while (true) {
int r = moveTo(keys.begin);
if (r < 0)
moveNext();
if (!valid || (db.fragment_values ? decodeKVFragment(getEncodedRow()).get().key
: decodeKV(getEncodedRow()).key) >= keys.end)
break;
remove();
}
}
void fastClear(KeyRangeRef keys, bool& freeTableEmpty) {
std::vector<int> clearBuffer(SERVER_KNOBS->CLEAR_BUFFER_SIZE);
clearBuffer[0] = 0;
while (true) {
if (moveTo(keys.begin) < 0)
moveNext();
RawCursor endCursor(db, db.table, false);
if (endCursor.moveTo(keys.end) >= 0)
endCursor.movePrevious();
if (!valid || !endCursor ||
(db.fragment_values ? (decodeKVFragment(getEncodedRow()).get().key >=
decodeKVFragment(endCursor.getEncodedRow()).get().key)
: (decodeKV(getEncodedRow()).key > decodeKV(endCursor.getEncodedRow()).key)))
break; // If empty stop!
int rc = sqlite3BtreeDeleteRange(
cursor, endCursor.cursor, &clearBuffer[0], &clearBuffer[0] + clearBuffer.size());
if (rc == 201)
continue;
if (!rc)
break;
db.checkError("BtreeDeleteRange", rc);
}
if (clearBuffer[0]) {
// printf("fastClear(%s,%s): %d pages freed\n", printable(keys.begin).c_str(), printable(keys.end).c_str(),
// clearBuffer[0]);
IntKeyCursor fc(db, db.freetable, true);
int pagesDeleted = 0;
db.checkError("BtreeLazyDelete",
sqlite3BtreeLazyDelete(
fc.cursor, &clearBuffer[0], &clearBuffer[0] + clearBuffer.size(), 0, &pagesDeleted));
ASSERT(pagesDeleted == 0);
freeTableEmpty = false;
}
}
int lazyDelete(int desiredPages) {
std::vector<int> clearBuffer(SERVER_KNOBS->CLEAR_BUFFER_SIZE);
clearBuffer[0] = 0;
IntKeyCursor fc(db, db.freetable, true);
int pagesDeleted = 0;
db.checkError(
"BtreeLazyDelete",
sqlite3BtreeLazyDelete(
fc.cursor, &clearBuffer[0], &clearBuffer[0] + clearBuffer.size(), desiredPages, &pagesDeleted));
return pagesDeleted;
}
// Reads and reconstitutes kv fragments given cursor, an arena to allocate in, and a direction to move the cursor.
// getNext() returns the next KV pair, if there is one
// peek() returns the next key that would be read by getNext(), if there is one
// Both methods return Optionals.
// Once either method returns a non-present value, using the DefragmentingReader again is undefined behavior.
struct DefragmentingReader {
// Use this constructor for forward/backward range reads
DefragmentingReader(RawCursor& cur, Arena& m, bool forward)
: cur(cur), arena(m), forward(forward), fragmentReadLimit(-1) {
parse();
}
// Use this constructor to read a SINGLE partial value from the current cursor position for an expected key.
// This exists to support IKeyValueStore::getPrefix().
// The reader will return exactly one KV pair if its key matches expectedKey, otherwise no KV pairs.
DefragmentingReader(RawCursor& cur, Arena& m, KeyRef expectedKey, int maxValueLen)
: cur(cur), arena(m), forward(true), maxValueLen(maxValueLen) {
fragmentReadLimit = getEncodedKVFragmentSize(expectedKey.size(), maxValueLen);
parse();
// If a key was found but it wasn't the expected key then
// clear the current kv pair and invalidate the cursor.
if (kv.present() && kv.get().key != expectedKey) {
kv = Optional<KeyValueRef>();
cur.valid = false;
}
}
private:
Optional<KeyValueRef> kv; // key and latest value fragment read
uint32_t index; // index of latest value fragment read
RawCursor& cur; // Cursor to read from
Arena& arena; // Arena to allocate key and value bytes in
bool forward; // true for forward iteration, false for reverse
int maxValueLen; // truncated value length to return
int fragmentReadLimit; // If >= 0, only read and *attempt* to decode this many fragment bytes
// Update kv with whatever is at the current cursor position if the position is valid.
void parse() {
if (cur.valid) {
// The read is either not partial or it is but the fragment read limit is at least 4 (the size of a
// minimal header).
bool partial = fragmentReadLimit >= 0;
ASSERT(!partial || fragmentReadLimit >= 4);
// Read full or part of fragment
ValueRef encoded =
(partial) ? cur.getEncodedRowPrefix(arena, fragmentReadLimit) : cur.getEncodedRow(arena);
kv = decodeKVFragment(encoded, &index, partial);
// If this was a partial fragment then if successful update the next fragment read size, and if not
// then invalidate the cursor.
if (partial) {
if (kv.present())
fragmentReadLimit -= kv.get().value.size();
else
cur.valid = false;
}
} else
kv = Optional<KeyValueRef>();
}
// advance cursor, parse and return key if valid
Optional<KeyRef> advance() {
if (cur.valid) {
forward ? cur.moveNext() : cur.movePrevious();
parse();
}
return kv.present() ? kv.get().key : Optional<KeyRef>();
}
public:
// Get the next key that would be returned by getNext(), if there is one
// This is more efficient than getNext() if the caller is not sure if it wants the next KV pair
Optional<KeyRef> peek() {
if (kv.present())
return kv.get().key;
return advance();
}
Optional<KeyValueRef> getNext() {
if (!peek().present())
return Optional<KeyValueRef>();
bool partial = fragmentReadLimit >= 0;
// Start out with the next KV fragment as the pair to return
KeyValueRef resultKV = kv.get();
// If index is 0 then this is an unfragmented key. It is unnecessary to advance the cursor so
// we won't, but we will clear kv so that the next peek/getNext will have to advance.
if (index == 0)
kv = Optional<KeyValueRef>();
else {
// First and last indexes in fragment group are size hints.
// First index is ceil(total_value_size / 4)
// Last index is ceil(total_value_size / 2)
// Set size depending on which of these will be first encountered and allocate buffer in arena.
// Note that if these index hints are wrong (such as if the index scheme changes) then asserts
// below will fail. They will have to be changed to expand the buffer as needed.
int size = forward ? (index * KV_FRAGMENT_INDEX_SIZE_HINT_FACTOR)
: (index * (KV_FRAGMENT_INDEX_SIZE_HINT_FACTOR / 2));
uint8_t* buf = new (arena) uint8_t[size];
uint8_t* bufEnd = buf + size;
// For forward iteration wptr is the place to write to next, for reverse it's where the last write
// started.
uint8_t* wptr = forward ? buf : bufEnd;
int fragments = 0;
do {
++fragments;
const ValueRef& val = kv.get().value;
if (forward) {
uint8_t* w = wptr;
wptr += val.size();
ASSERT(wptr <= bufEnd);
memcpy(w, val.begin(), val.size());
// If this is a partial value get and we have enough bytes we can stop since we are forward
// iterating.
if (partial && wptr - buf >= maxValueLen) {
resultKV.value = ValueRef(buf, maxValueLen);
// To make further calls to peek() or getNext() return nothing, reset kv and invalidate
// cursor
kv = Optional<KeyValueRef>();
cur.valid = false;
return resultKV;
}
} else {
wptr -= val.size();
ASSERT(wptr >= buf);
memcpy(wptr, val.begin(), val.size());
}
} while (advance().present() && kv.get().key == resultKV.key);
// If there was only 1 fragment, it should have been index 0 and handled above,
ASSERT(fragments != 1);
// Set final value based on direction of buffer fill
resultKV.value = forward ? ValueRef(buf, wptr - buf) : ValueRef(wptr, bufEnd - wptr);
}
// In partial value mode, we could end up here if there was only 1 fragments or maxValueLen
// was greater than the total unfragmented value size.
if (partial)
resultKV.value = resultKV.value.substr(0, std::min(resultKV.value.size(), maxValueLen));
return resultKV;
}
};
Optional<Value> get(KeyRef key) {
int r = moveTo(key);
if (db.fragment_values) {
// Optimization - moveTo seeks to fragment (key, 0) so if it was exactly found then we
// know we have a single fragment for key and can return it.
if (r == 0) {
Value result;
((ValueRef&)result) = decodeKVFragment(getEncodedRow(result.arena())).get().value;
return result;
}
// Otherwise see if the fragments immediately after (key, 0) are for the key we want.
if (r < 0)
moveNext();
Arena m;
DefragmentingReader i(*this, m, true);
if (i.peek() == key) {
Optional<KeyValueRef> kv = i.getNext();
return Value(kv.get().value, m);
}
} else if (r == 0) {
Value result;
KeyValueRef kv = decodeKV(getEncodedRow(result.arena()));
((ValueRef&)result) = kv.value;
return result;
}
return Optional<Value>();
}
Optional<Value> getPrefix(KeyRef key, int maxLength) {
if (db.fragment_values) {
int r = moveTo(key);
if (r < 0)
moveNext();
Arena m;
DefragmentingReader i(*this, m, getEncodedKVFragmentSize(key.size(), maxLength));
if (i.peek() == key) {
Optional<KeyValueRef> kv = i.getNext();
return Value(kv.get().value, m);
}
} else if (!moveTo(key)) {
if (maxLength == 0) {
return Value();
}
Value result;
int maxEncodedSize = getEncodedSize(key.size(), maxLength);
KeyValueRef kv = decodeKVPrefix(getEncodedRowPrefix(result.arena(), maxEncodedSize), maxLength);
((ValueRef&)result) = kv.value;
return result;
}
return Optional<Value>();
}
RangeResult getRange(KeyRangeRef keys, int rowLimit, int byteLimit) {
RangeResult result;
int accumulatedBytes = 0;
ASSERT(byteLimit > 0);
if (rowLimit == 0) {
return result;
}
if (db.fragment_values) {
if (rowLimit > 0) {
int r = moveTo(keys.begin);
if (r < 0)
moveNext();
DefragmentingReader i(*this, result.arena(), true);
Optional<KeyRef> nextKey = i.peek();
while (nextKey.present() && nextKey.get() < keys.end && rowLimit != 0 && accumulatedBytes < byteLimit) {
Optional<KeyValueRef> kv = i.getNext();
result.push_back(result.arena(), kv.get());
--rowLimit;
accumulatedBytes += sizeof(KeyValueRef) + kv.get().expectedSize();
nextKey = i.peek();
}
} else {
int r = moveTo(keys.end);
if (r >= 0)
movePrevious();
DefragmentingReader i(*this, result.arena(), false);
Optional<KeyRef> nextKey = i.peek();
while (nextKey.present() && nextKey.get() >= keys.begin && rowLimit != 0 &&
accumulatedBytes < byteLimit) {
Optional<KeyValueRef> kv = i.getNext();
result.push_back(result.arena(), kv.get());
++rowLimit;
accumulatedBytes += sizeof(KeyValueRef) + kv.get().expectedSize();
nextKey = i.peek();
}
}
} else {
if (rowLimit > 0) {
int r = moveTo(keys.begin);
if (r < 0)
moveNext();
while (this->valid && rowLimit != 0 && accumulatedBytes < byteLimit) {
KeyValueRef kv = decodeKV(getEncodedRow(result.arena()));
if (kv.key >= keys.end)
break;
--rowLimit;
accumulatedBytes += sizeof(KeyValueRef) + kv.expectedSize();
result.push_back(result.arena(), kv);
moveNext();
}
} else {
int r = moveTo(keys.end);
if (r >= 0)
movePrevious();
while (this->valid && rowLimit != 0 && accumulatedBytes < byteLimit) {
KeyValueRef kv = decodeKV(getEncodedRow(result.arena()));
if (kv.key < keys.begin)
break;
++rowLimit;
accumulatedBytes += sizeof(KeyValueRef) + kv.expectedSize();
result.push_back(result.arena(), kv);
movePrevious();
}
}
}
result.more = rowLimit == 0 || accumulatedBytes >= byteLimit;
if (result.more) {
ASSERT(result.size() > 0);
result.readThrough = result[result.size() - 1].key;
}
return result;
}
int moveTo(KeyRef key, bool ignore_fragment_mode = false) {
UnpackedRecord r;
r.pKeyInfo = &keyInfo;
r.flags =
UNPACKED_PREFIX_MATCH; // This record [key] can be considered equal to a record [key,value] for any value
Mem tupleValues[2];
r.aMem = tupleValues;
// Set field 1 of tuple to key, which is a string type with typecode 12 + 2*len
tupleValues[0].db = keyInfo.db;
tupleValues[0].enc = keyInfo.enc;
tupleValues[0].zMalloc = nullptr;
ASSERT(sqlite3VdbeSerialGet(key.begin(), 12 + (2 * key.size()), &tupleValues[0]) == key.size());
// In fragmenting mode, seek is to (k, 0, ), otherwise just (k, ).
if (ignore_fragment_mode || !db.fragment_values)
r.nField = 1;
else {
// Set field 2 of tuple to the null type which is typecode 0
tupleValues[1].db = keyInfo.db;
tupleValues[1].enc = keyInfo.enc;
tupleValues[1].zMalloc = nullptr;
ASSERT(sqlite3VdbeSerialGet(nullptr, 0, &tupleValues[1]) == 0);
r.nField = 2;
}
int result;
db.checkError("BtreeMovetoUnpacked", sqlite3BtreeMovetoUnpacked(cursor, &r, 0, 0, &result));
valid = result >= 0 || !sqlite3BtreeEof(cursor);
return result;
}
};
struct Cursor : SQLiteTransaction, RawCursor {
Cursor(SQLiteDB& db, bool write) : SQLiteTransaction(db, write), RawCursor(db, db.table, write) {}
};
struct ReadCursor : ReferenceCounted<ReadCursor>, FastAllocated<ReadCursor> {
// Readers need to be reset (forced to move to a new snapshot) when the writer thread does a checkpoint.
// ReadCursor is reference counted so that the writer can clear the persistent reference (readCursors[n]) and
// readers can hold an additional reference when they actually have a read happening.
// ReadCursor lazily constructs its actual Cursor (and hence transaction) because it's vital that readCursors[n] be
// assigned before the transaction is opened.
ReadCursor() : valid(false) {}
void init(SQLiteDB& db) {
new (&cursor) Cursor(db, false);
valid = true;
}
~ReadCursor() {
if (valid)
get().~Cursor();
}
Cursor& get() { return *((Cursor*)&cursor); }
private:
std::aligned_storage<sizeof(Cursor), __alignof(Cursor)>::type cursor;
bool valid;
};
extern bool vfsAsyncIsOpen(std::string filename);
// Returns number of pages which failed checksum.
int SQLiteDB::checkAllPageChecksums() {
ASSERT(!haveMutex);
ASSERT(page_checksums); // This should never be called on SQLite databases that do not have page checksums.
double startT = timer();
// First try to open an existing file
std::string apath = abspath(filename);
std::string walpath = apath + "-wal";
/* REMOVE THIS BEFORE CHECKIN */ if (!fileExists(apath))
return 0;
TraceEvent("SQLitePageChecksumScanBegin").detail("File", apath);
ErrorOr<Reference<IAsyncFile>> dbFile = waitForAndGet(
errorOr(IAsyncFileSystem::filesystem()->open(apath, IAsyncFile::OPEN_READONLY | IAsyncFile::OPEN_LOCK, 0)));
ErrorOr<Reference<IAsyncFile>> walFile = waitForAndGet(
errorOr(IAsyncFileSystem::filesystem()->open(walpath, IAsyncFile::OPEN_READONLY | IAsyncFile::OPEN_LOCK, 0)));
if (dbFile.isError())
throw dbFile.getError(); // If we've failed to open the file, throw an exception
if (walFile.isError())
throw walFile.getError(); // If we've failed to open the file, throw an exception
// Now that the file itself is open and locked, let sqlite open the database
// Note that VFSAsync will also call g_network->open (including for the WAL), so its flags are important, too
// TODO: If better performance is needed, make AsyncFileReadAheadCache work and be enabled by SQLITE_OPEN_READAHEAD
// which was added for that purpose.
int result = sqlite3_open_v2(apath.c_str(), &db, SQLITE_OPEN_READONLY, nullptr);
checkError("open", result);
// This check has the useful side effect of actually opening/reading the database. If we were not doing this,
// then we could instead open a read cursor for the same effect, as currently tryReadEveryDbPage() requires it.
Statement* jm = new Statement(*this, "PRAGMA journal_mode");
ASSERT(jm->nextRow());
if (jm->column(0) != LiteralStringRef("wal")) {
TraceEvent(SevError, "JournalModeError").detail("Filename", filename).detail("Mode", jm->column(0));
ASSERT(false);
}
delete jm;
btree = db->aDb[0].pBt;
initPagerCodec();
sqlite3_extended_result_codes(db, 1);
sqlite3_mutex_enter(db->mutex);
haveMutex = true;
pPagerCodec->silent = true;
Pgno p = 1;
int readErrors = 0;
int corruptPages = 0;
int totalErrors = 0;
while (1) {
int type;
int zero;
int rc = tryReadEveryDbPage(db, p, &p, &type, &zero);
if (rc == SQLITE_OK)
break;
if (rc == SQLITE_CORRUPT) {
TraceEvent(SevWarnAlways, "SQLitePageChecksumScanCorruptPage")
.detail("File", filename)
.detail("PageNumber", p)
.detail("PageType", type)
.detail("PageWasZeroed", zero);
++corruptPages;
} else {
TraceEvent(SevWarnAlways, "SQLitePageChecksumScanReadFailed")
.detail("File", filename)
.detail("PageNumber", p)
.detail("SQLiteError", sqlite3ErrStr(rc))
.detail("SQLiteErrorCode", rc);
++readErrors;
}
++p;
if (++totalErrors >= SERVER_KNOBS->SQLITE_PAGE_SCAN_ERROR_LIMIT)
break;
}
pPagerCodec->silent = false;
haveMutex = false;
sqlite3_mutex_leave(db->mutex);
sqlite3_close(db);
TraceEvent("SQLitePageChecksumScanEnd")
.detail("Elapsed", DEBUG_DETERMINISM ? 0 : timer() - startT)
.detail("Filename", filename)
.detail("CorruptPages", corruptPages)
.detail("ReadErrors", readErrors)
.detail("TotalErrors", totalErrors);
ASSERT(!vfsAsyncIsOpen(filename));
ASSERT(!vfsAsyncIsOpen(filename + "-wal"));
return totalErrors;
}
void SQLiteDB::open(bool writable) {
ASSERT(!haveMutex);
double startT = timer();
//TraceEvent("KVThreadInitStage").detail("Stage",1).detail("Filename", filename).detail("Writable", writable);
// First try to open an existing file
std::string apath = abspath(filename);
std::string walpath = apath + "-wal";
ErrorOr<Reference<IAsyncFile>> dbFile = waitForAndGet(
errorOr(IAsyncFileSystem::filesystem()->open(apath, IAsyncFile::OPEN_READWRITE | IAsyncFile::OPEN_LOCK, 0)));
ErrorOr<Reference<IAsyncFile>> walFile = waitForAndGet(
errorOr(IAsyncFileSystem::filesystem()->open(walpath, IAsyncFile::OPEN_READWRITE | IAsyncFile::OPEN_LOCK, 0)));
//TraceEvent("KVThreadInitStage").detail("Stage",15).detail("Filename", apath).detail("Writable", writable).detail("IsErr", dbFile.isError());
if (writable) {
if (dbFile.isError() && dbFile.getError().code() == error_code_file_not_found &&
!fileExists(apath) && // db file is missing
!walFile.isError() && fileExists(walpath)) // ..but WAL file is present
{
// Either we died partway through creating this DB, or died partway through deleting it, or someone is
// monkeying with our files Create a new blank DB by backing up the WAL file (just in case it is important)
// and then hitting the next case
walFile = file_not_found();
renameFile(walpath, walpath + "-old-" + deterministicRandom()->randomUniqueID().toString());
ASSERT_WE_THINK(false); //< This code should not be hit in FoundationDB at the moment, because worker looks
// for databases to open by listing .fdb files, not .fdb-wal files
// TEST(true); // Replace a partially constructed or destructed DB
}
if (dbFile.isError() && walFile.isError() && writable &&
dbFile.getError().code() == error_code_file_not_found &&
walFile.getError().code() == error_code_file_not_found && !fileExists(apath) && !fileExists(walpath)) {
// The file doesn't exist, try to create a new one
// Creating the WAL before the database ensures we will not try to open a database with no WAL
walFile = waitForAndGet(IAsyncFileSystem::filesystem()->open(
walpath,
IAsyncFile::OPEN_ATOMIC_WRITE_AND_CREATE | IAsyncFile::OPEN_CREATE | IAsyncFile::OPEN_READWRITE |
IAsyncFile::OPEN_LOCK,
0600));
waitFor(walFile.get()->sync());
dbFile = waitForAndGet(IAsyncFileSystem::filesystem()->open(
apath,
IAsyncFile::OPEN_ATOMIC_WRITE_AND_CREATE | IAsyncFile::OPEN_CREATE | IAsyncFile::OPEN_READWRITE |
IAsyncFile::OPEN_LOCK,
0600));
if (page_checksums)
waitFor(
dbFile.get()->write(template_fdb_with_page_checksums, sizeof(template_fdb_with_page_checksums), 0));
else
waitFor(dbFile.get()->write(
template_fdb_without_page_checksums, sizeof(template_fdb_without_page_checksums), 0));
waitFor(dbFile.get()->sync()); // renames filename.part to filename, fsyncs data and directory
TraceEvent("CreatedDBFile").detail("Filename", apath);
}
}
if (dbFile.isError())
throw dbFile.getError(); // If we've failed to open the file, throw an exception
if (walFile.isError())
throw walFile.getError(); // If we've failed to open the file, throw an exception
// Set Rate control if SERVER_KNOBS are positive
if (SERVER_KNOBS->SQLITE_WRITE_WINDOW_LIMIT > 0 && SERVER_KNOBS->SQLITE_WRITE_WINDOW_SECONDS > 0) {
// The writer thread is created before the readers, so it should initialize the rate controls.
if (writable) {
// Create a new rate control and assign it to both files.
Reference<SpeedLimit> rc(
new SpeedLimit(SERVER_KNOBS->SQLITE_WRITE_WINDOW_LIMIT, SERVER_KNOBS->SQLITE_WRITE_WINDOW_SECONDS));
dbFile.get()->setRateControl(rc);
walFile.get()->setRateControl(rc);
} else {
// When a reader thread is opened, the rate controls should already be equal and not null
ASSERT(dbFile.get()->getRateControl() == walFile.get()->getRateControl());
ASSERT(dbFile.get()->getRateControl());
}
}
//TraceEvent("KVThreadInitStage").detail("Stage",2).detail("Filename", filename).detail("Writable", writable);
// Now that the file itself is open and locked, let sqlite open the database
// Note that VFSAsync will also call g_network->open (including for the WAL), so its flags are important, too
int result =
sqlite3_open_v2(apath.c_str(), &db, (writable ? SQLITE_OPEN_READWRITE : SQLITE_OPEN_READONLY), nullptr);
checkError("open", result);
int chunkSize;
if (!g_network->isSimulated()) {
chunkSize = 4096 * SERVER_KNOBS->SQLITE_CHUNK_SIZE_PAGES;
} else if (BUGGIFY) {
chunkSize = 4096 * deterministicRandom()->randomInt(0, 100);
} else {
chunkSize = 4096 * SERVER_KNOBS->SQLITE_CHUNK_SIZE_PAGES_SIM;
}
checkError("setChunkSize", sqlite3_file_control(db, nullptr, SQLITE_FCNTL_CHUNK_SIZE, &chunkSize));
btree = db->aDb[0].pBt;
initPagerCodec();
sqlite3_extended_result_codes(db, 1);
//TraceEvent("KVThreadInitStage").detail("Stage",3).detail("Filename", filename).detail("Writable", writable);
// Statement(*this, "PRAGMA cache_size = 100").execute();
Statement jm(*this, "PRAGMA journal_mode");
ASSERT(jm.nextRow());
if (jm.column(0) != LiteralStringRef("wal")) {
TraceEvent(SevError, "JournalModeError").detail("Filename", filename).detail("Mode", jm.column(0));
ASSERT(false);
}
if (writable) {
Statement(*this, "PRAGMA synchronous = NORMAL").execute(); // OFF, NORMAL, FULL
Statement(*this, "PRAGMA wal_autocheckpoint = -1").nextRow();
}
//TraceEvent("KVThreadInitStage").detail("Stage",4).detail("Filename", filename).detail("Writable", writable);
sqlite3_mutex_enter(db->mutex);
haveMutex = true;
table = 3;
freetable = 4;
this->dbFile = dbFile.get();
this->walFile = walFile.get();
TraceEvent("KVThreadInitTime")
.detail("Elapsed", DEBUG_DETERMINISM ? 0 : timer() - startT)
.detail("Filename", filename)
.detail("Writable", writable);
ASSERT(vfsAsyncIsOpen(filename));
}
void SQLiteDB::createFromScratch() {
int sqliteFlags = SQLITE_OPEN_READWRITE | SQLITE_OPEN_CREATE;
checkError("open", sqlite3_open_v2(filename.c_str(), &db, sqliteFlags, nullptr));
Statement(*this, "PRAGMA page_size = 4096").nextRow(); // fast
btree = db->aDb[0].pBt;
initPagerCodec();
Statement(*this, "PRAGMA auto_vacuum = 2").nextRow(); // slow all the time
Statement(*this, "PRAGMA journal_mode = WAL").nextRow(); // sometimes slow
sqlite3_extended_result_codes(db, 1);
sqlite3_mutex_enter(db->mutex);
haveMutex = true;
beginTransaction(true);
u32 pgnoRoot = -1;
sqlite3BtreeGetMeta(btree, BTREE_LARGEST_ROOT_PAGE, &pgnoRoot);
// We expect our tables are #3, #4 (since autovacuum is enabled, there is a pointer map page at #2)
if (pgnoRoot == 4) {
table = pgnoRoot - 1;
freetable = pgnoRoot;
rollback();
} else if (pgnoRoot == 1) {
// The database is empty; create tables
checkError("BtreeCreateTable", sqlite3BtreeCreateTable(btree, &table, BTREE_BLOBKEY));
ASSERT(table == 3);
checkError("BtreeCreateTable2", sqlite3BtreeCreateTable(btree, &freetable, BTREE_INTKEY));
ASSERT(freetable == table + 1);
endTransaction();
} else {
TraceEvent("PgnoRoot").detail("Value", pgnoRoot);
checkError("CheckTables", SQLITE_CORRUPT);
}
}
struct ThreadSafeCounter {
volatile int64_t counter;
ThreadSafeCounter() : counter(0) {}
void operator++() { interlockedIncrement64(&counter); }
void operator--() { interlockedDecrement64(&counter); }
operator int64_t() const { return counter; }
};
class KeyValueStoreSQLite final : public IKeyValueStore {
public:
void dispose() override { doClose(this, true); }
void close() override { doClose(this, false); }
Future<Void> getError() override { return delayed(readThreads->getError() || writeThread->getError()); }
Future<Void> onClosed() override { return stopped.getFuture(); }
KeyValueStoreType getType() const override { return type; }
StorageBytes getStorageBytes() const override;
void set(KeyValueRef keyValue, const Arena* arena = nullptr) override;
void clear(KeyRangeRef range, const Arena* arena = nullptr) override;
Future<Void> commit(bool sequential = false) override;
Future<Optional<Value>> readValue(KeyRef key, Optional<UID> debugID) override;
Future<Optional<Value>> readValuePrefix(KeyRef key, int maxLength, Optional<UID> debugID) override;
Future<RangeResult> readRange(KeyRangeRef keys, int rowLimit = 1 << 30, int byteLimit = 1 << 30) override;
KeyValueStoreSQLite(std::string const& filename,
UID logID,
KeyValueStoreType type,
bool checkChecksums,
bool checkIntegrity);
~KeyValueStoreSQLite() override;
struct SpringCleaningWorkPerformed {
int lazyDeletePages = 0;
int vacuumedPages = 0;
};
Future<SpringCleaningWorkPerformed> doClean();
void startReadThreads();
private:
KeyValueStoreType type;
UID logID;
std::string filename;
Reference<IThreadPool> readThreads, writeThread;
Promise<Void> stopped;
Future<Void> cleaning, logging, starting, stopOnErr;
int64_t readsRequested, writesRequested;
ThreadSafeCounter readsComplete;
volatile int64_t writesComplete;
volatile SpringCleaningStats springCleaningStats;
volatile int64_t diskBytesUsed;
volatile int64_t freeListPages;
std::vector<Reference<ReadCursor>> readCursors;
Reference<IAsyncFile> dbFile, walFile;
struct Reader : IThreadPoolReceiver {
SQLiteDB conn;
ThreadSafeCounter& counter;
UID dbgid;
Reference<ReadCursor>* ppReadCursor;
explicit Reader(std::string const& filename,
bool is_btree_v2,
ThreadSafeCounter& counter,
UID dbgid,
Reference<ReadCursor>* ppReadCursor)
: conn(filename, is_btree_v2, is_btree_v2), counter(counter), dbgid(dbgid), ppReadCursor(ppReadCursor) {}
~Reader() override { ppReadCursor->clear(); }
void init() override { conn.open(false); }
Reference<ReadCursor> getCursor() {
Reference<ReadCursor> cursor = *ppReadCursor;
if (!cursor) {
*ppReadCursor = cursor = makeReference<ReadCursor>();
cursor->init(conn);
}
return cursor;
}
struct ReadValueAction final : TypedAction<Reader, ReadValueAction>, FastAllocated<ReadValueAction> {
Key key;
Optional<UID> debugID;
ThreadReturnPromise<Optional<Value>> result;
ReadValueAction(Key key, Optional<UID> debugID) : key(key), debugID(debugID){};
double getTimeEstimate() const override { return SERVER_KNOBS->READ_VALUE_TIME_ESTIMATE; }
};
void action(ReadValueAction& rv) {
// double t = timer();
if (rv.debugID.present())
g_traceBatch.addEvent("GetValueDebug",
rv.debugID.get().first(),
"Reader.Before"); //.detail("TaskID", g_network->getCurrentTask());
rv.result.send(getCursor()->get().get(rv.key));
++counter;
if (rv.debugID.present())
g_traceBatch.addEvent("GetValueDebug",
rv.debugID.get().first(),
"Reader.After"); //.detail("TaskID", g_network->getCurrentTask());
// t = timer()-t;
// if (t >= 1.0) TraceEvent("ReadValueActionSlow",dbgid).detail("Elapsed", t);
}
struct ReadValuePrefixAction final : TypedAction<Reader, ReadValuePrefixAction>,
FastAllocated<ReadValuePrefixAction> {
Key key;
int maxLength;
Optional<UID> debugID;
ThreadReturnPromise<Optional<Value>> result;
ReadValuePrefixAction(Key key, int maxLength, Optional<UID> debugID)
: key(key), maxLength(maxLength), debugID(debugID){};
double getTimeEstimate() const override { return SERVER_KNOBS->READ_VALUE_TIME_ESTIMATE; }
};
void action(ReadValuePrefixAction& rv) {
// double t = timer();
if (rv.debugID.present())
g_traceBatch.addEvent("GetValuePrefixDebug",
rv.debugID.get().first(),
"Reader.Before"); //.detail("TaskID", g_network->getCurrentTask());
rv.result.send(getCursor()->get().getPrefix(rv.key, rv.maxLength));
++counter;
if (rv.debugID.present())
g_traceBatch.addEvent("GetValuePrefixDebug",
rv.debugID.get().first(),
"Reader.After"); //.detail("TaskID", g_network->getCurrentTask());
// t = timer()-t;
// if (t >= 1.0) TraceEvent("ReadValuePrefixActionSlow",dbgid).detail("Elapsed", t);
}
struct ReadRangeAction final : TypedAction<Reader, ReadRangeAction>, FastAllocated<ReadRangeAction> {
KeyRange keys;
int rowLimit, byteLimit;
ThreadReturnPromise<RangeResult> result;
ReadRangeAction(KeyRange keys, int rowLimit, int byteLimit)
: keys(keys), rowLimit(rowLimit), byteLimit(byteLimit) {}
double getTimeEstimate() const override { return SERVER_KNOBS->READ_RANGE_TIME_ESTIMATE; }
};
void action(ReadRangeAction& rr) {
rr.result.send(getCursor()->get().getRange(rr.keys, rr.rowLimit, rr.byteLimit));
++counter;
}
};
struct Writer : IThreadPoolReceiver {
KeyValueStoreSQLite* kvs;
SQLiteDB conn;
Cursor* cursor;
int commits;
int setsThisCommit;
bool freeTableEmpty; // true if we are sure the freetable (pages pending lazy deletion) is empty
volatile int64_t& writesComplete;
volatile SpringCleaningStats& springCleaningStats;
volatile int64_t& diskBytesUsed;
volatile int64_t& freeListPages;
UID dbgid;
std::vector<Reference<ReadCursor>>& readThreads;
bool checkAllChecksumsOnOpen;
bool checkIntegrityOnOpen;
explicit Writer(KeyValueStoreSQLite* kvs,
bool isBtreeV2,
bool checkAllChecksumsOnOpen,
bool checkIntegrityOnOpen,
volatile int64_t& writesComplete,
volatile SpringCleaningStats& springCleaningStats,
volatile int64_t& diskBytesUsed,
volatile int64_t& freeListPages,
UID dbgid,
std::vector<Reference<ReadCursor>>* pReadThreads)
: kvs(kvs), conn(kvs->filename, isBtreeV2, isBtreeV2), cursor(nullptr), commits(), setsThisCommit(),
freeTableEmpty(false), writesComplete(writesComplete), springCleaningStats(springCleaningStats),
diskBytesUsed(diskBytesUsed), freeListPages(freeListPages), dbgid(dbgid), readThreads(*pReadThreads),
checkAllChecksumsOnOpen(checkAllChecksumsOnOpen), checkIntegrityOnOpen(checkIntegrityOnOpen) {}
~Writer() override {
TraceEvent("KVWriterDestroying", dbgid).log();
delete cursor;
TraceEvent("KVWriterDestroyed", dbgid).log();
}
void init() override {
if (checkAllChecksumsOnOpen) {
if (conn.checkAllPageChecksums() != 0) {
// It's not strictly necessary to discard the file immediately if a page checksum error is found
// because most of the file could be valid and bad pages will be detected if they are read.
// However, we shouldn't use the file unless we absolutely have to because some range(s) of keys
// have effectively lost a replica.
throw file_corrupt();
}
}
conn.open(true);
kvs->dbFile = conn.dbFile;
kvs->walFile = conn.walFile;
// If a wal file fails during the commit process before finishing a checkpoint, then it is possible that our
// wal file will be non-empty when we reload it. We execute a checkpoint here to remedy that situation.
// This call must come before before creating a cursor because it will fail if there are any outstanding
// transactions.
fullCheckpoint();
cursor = new Cursor(conn, true);
if (checkIntegrityOnOpen || EXPENSIVE_VALIDATION) {
if (conn.check(false) != 0) {
// A corrupt btree structure must not be used.
if (g_network->isSimulated() && VFSAsyncFile::checkInjectedError()) {
throw file_corrupt().asInjectedFault();
} else {
throw file_corrupt();
}
}
}
}
struct InitAction final : TypedAction<Writer, InitAction>, FastAllocated<InitAction> {
ThreadReturnPromise<Void> result;
double getTimeEstimate() const override { return 0; }
};
void action(InitAction& a) {
// init() has already been called
a.result.send(Void());
}
struct SetAction final : TypedAction<Writer, SetAction>, FastAllocated<SetAction> {
KeyValue kv;
SetAction(KeyValue kv) : kv(kv) {}
double getTimeEstimate() const override { return SERVER_KNOBS->SET_TIME_ESTIMATE; }
};
void action(SetAction& a) {
double s = now();
checkFreePages();
cursor->set(a.kv);
++setsThisCommit;
++writesComplete;
if (g_network->isSimulated() && g_simulator.getCurrentProcess()->rebooting)
TraceEvent("SetActionFinished", dbgid).detail("Elapsed", now() - s);
}
struct ClearAction final : TypedAction<Writer, ClearAction>, FastAllocated<ClearAction> {
KeyRange range;
ClearAction(KeyRange range) : range(range) {}
double getTimeEstimate() const override { return SERVER_KNOBS->CLEAR_TIME_ESTIMATE; }
};
void action(ClearAction& a) {
double s = now();
cursor->fastClear(a.range, freeTableEmpty);
cursor->clear(a.range); // TODO: at most one
++writesComplete;
if (g_network->isSimulated() && g_simulator.getCurrentProcess()->rebooting)
TraceEvent("ClearActionFinished", dbgid).detail("Elapsed", now() - s);
}
struct CommitAction final : TypedAction<Writer, CommitAction>, FastAllocated<CommitAction> {
double issuedTime;
ThreadReturnPromise<Void> result;
CommitAction() : issuedTime(now()) {}
double getTimeEstimate() const override { return SERVER_KNOBS->COMMIT_TIME_ESTIMATE; }
};
void action(CommitAction& a) {
double t1 = now();
cursor->commit();
delete cursor;
cursor = nullptr;
double t2 = now();
fullCheckpoint();
double t3 = now();
++commits;
// if ( !(commits % 100) )
// printf("dbf=%lld bytes, wal=%lld bytes\n", getFileSize((kv->filename+".fdb").c_str()),
// getFileSize((kv->filename+".fdb-wal").c_str()));
a.result.send(Void());
cursor = new Cursor(conn, true);
checkFreePages();
++writesComplete;
if (t3 - a.issuedTime > 10.0 * deterministicRandom()->random01())
TraceEvent("KVCommit10sSample", dbgid)
.detail("Queued", t1 - a.issuedTime)
.detail("Commit", t2 - t1)
.detail("Checkpoint", t3 - t2);
diskBytesUsed = waitForAndGet(conn.dbFile->size()) + waitForAndGet(conn.walFile->size());
if (g_network->isSimulated() && g_simulator.getCurrentProcess()->rebooting)
TraceEvent("CommitActionFinished", dbgid).detail("Elapsed", now() - t1);
}
// Checkpoints the database and resets the wal file back to the beginning
void fullCheckpoint() {
// A checkpoint cannot succeed while there is an outstanding transaction
ASSERT(cursor == nullptr);
resetReaders();
conn.checkpoint(false);
resetReaders();
conn.checkpoint(true);
}
void resetReaders() {
for (int i = 0; i < readThreads.size(); i++)
readThreads[i].clear();
}
void checkFreePages() {
int iterations = 0;
int64_t freeListSize = freeListPages;
while (!freeTableEmpty && freeListSize < SERVER_KNOBS->CHECK_FREE_PAGE_AMOUNT) {
int deletedPages = cursor->lazyDelete(SERVER_KNOBS->CHECK_FREE_PAGE_AMOUNT);
freeTableEmpty = (deletedPages != SERVER_KNOBS->CHECK_FREE_PAGE_AMOUNT);
springCleaningStats.lazyDeletePages += deletedPages;
++iterations;
freeListSize = conn.freePages();
}
freeListPages = freeListSize;
// if (iterations) printf("Lazy free: %d pages on freelist, %d iterations, freeTableEmpty=%d\n",
// freeListPages, iterationsi, freeTableEmpty);
}
struct SpringCleaningAction final : TypedAction<Writer, SpringCleaningAction>,
FastAllocated<SpringCleaningAction> {
ThreadReturnPromise<SpringCleaningWorkPerformed> result;
double getTimeEstimate() const override {
return std::max(SERVER_KNOBS->SPRING_CLEANING_LAZY_DELETE_TIME_ESTIMATE,
SERVER_KNOBS->SPRING_CLEANING_VACUUM_TIME_ESTIMATE);
}
};
void action(SpringCleaningAction& a) {
double s = now();
double lazyDeleteEnd = now() + SERVER_KNOBS->SPRING_CLEANING_LAZY_DELETE_TIME_ESTIMATE;
double vacuumEnd = now() + SERVER_KNOBS->SPRING_CLEANING_VACUUM_TIME_ESTIMATE;
SpringCleaningWorkPerformed workPerformed;
double lazyDeleteTime = 0;
double vacuumTime = 0;
const double lazyDeleteBatchProbability =
1.0 / (1 + SERVER_KNOBS->SPRING_CLEANING_VACUUMS_PER_LAZY_DELETE_PAGE *
std::max(1, SERVER_KNOBS->SPRING_CLEANING_LAZY_DELETE_BATCH_SIZE));
bool vacuumFinished = false;
loop {
double begin = now();
bool canDelete = !freeTableEmpty &&
(now() < lazyDeleteEnd || workPerformed.lazyDeletePages <
SERVER_KNOBS->SPRING_CLEANING_MIN_LAZY_DELETE_PAGES) &&
workPerformed.lazyDeletePages < SERVER_KNOBS->SPRING_CLEANING_MAX_LAZY_DELETE_PAGES;
bool canVacuum = !vacuumFinished &&
(now() < vacuumEnd ||
workPerformed.vacuumedPages < SERVER_KNOBS->SPRING_CLEANING_MIN_VACUUM_PAGES) &&
workPerformed.vacuumedPages < SERVER_KNOBS->SPRING_CLEANING_MAX_VACUUM_PAGES;
if (!canDelete && !canVacuum) {
break;
}
if (canDelete && (!canVacuum || deterministicRandom()->random01() < lazyDeleteBatchProbability)) {
TEST(canVacuum); // SQLite lazy deletion when vacuuming is active
TEST(!canVacuum); // SQLite lazy deletion when vacuuming is inactive
int pagesToDelete = std::max(
1,
std::min(SERVER_KNOBS->SPRING_CLEANING_LAZY_DELETE_BATCH_SIZE,
SERVER_KNOBS->SPRING_CLEANING_MAX_LAZY_DELETE_PAGES - workPerformed.lazyDeletePages));
int pagesDeleted = cursor->lazyDelete(pagesToDelete);
freeTableEmpty = (pagesDeleted != pagesToDelete);
workPerformed.lazyDeletePages += pagesDeleted;
lazyDeleteTime += now() - begin;
} else {
ASSERT(canVacuum);
TEST(canDelete); // SQLite vacuuming when lazy delete is active
TEST(!canDelete); // SQLite vacuuming when lazy delete is inactive
TEST(SERVER_KNOBS->SPRING_CLEANING_VACUUMS_PER_LAZY_DELETE_PAGE !=
0); // SQLite vacuuming with nonzero vacuums_per_lazy_delete_page
vacuumFinished = conn.vacuum();
if (!vacuumFinished) {
++workPerformed.vacuumedPages;
}
vacuumTime += now() - begin;
}
CoroThreadPool::waitFor(yield());
}
freeListPages = conn.freePages();
TEST(workPerformed.lazyDeletePages > 0); // Pages lazily deleted
TEST(workPerformed.vacuumedPages > 0); // Pages vacuumed
TEST(vacuumTime > 0); // Time spent vacuuming
TEST(lazyDeleteTime > 0); // Time spent lazy deleting
++springCleaningStats.springCleaningCount;
springCleaningStats.lazyDeletePages += workPerformed.lazyDeletePages;
springCleaningStats.vacuumedPages += workPerformed.vacuumedPages;
springCleaningStats.springCleaningTime += now() - s;
springCleaningStats.vacuumTime += vacuumTime;
springCleaningStats.lazyDeleteTime += lazyDeleteTime;
a.result.send(workPerformed);
++writesComplete;
if (g_network->isSimulated() && g_simulator.getCurrentProcess()->rebooting)
TraceEvent("SpringCleaningActionFinished", dbgid).detail("Elapsed", now() - s);
}
};
ACTOR static Future<Void> logPeriodically(KeyValueStoreSQLite* self) {
state int64_t lastReadsComplete = 0;
state int64_t lastWritesComplete = 0;
loop {
wait(delay(SERVER_KNOBS->DISK_METRIC_LOGGING_INTERVAL));
int64_t rc = self->readsComplete, wc = self->writesComplete;
TraceEvent("DiskMetrics", self->logID)
.detail("ReadOps", rc - lastReadsComplete)
.detail("WriteOps", wc - lastWritesComplete)
.detail("ReadQueue", self->readsRequested - rc)
.detail("WriteQueue", self->writesRequested - wc)
.detail("GlobalSQLiteMemoryHighWater", (int64_t)sqlite3_memory_highwater(1));
TraceEvent("SpringCleaningMetrics", self->logID)
.detail("SpringCleaningCount", self->springCleaningStats.springCleaningCount)
.detail("LazyDeletePages", self->springCleaningStats.lazyDeletePages)
.detail("VacuumedPages", self->springCleaningStats.vacuumedPages)
.detail("SpringCleaningTime", self->springCleaningStats.springCleaningTime)
.detail("LazyDeleteTime", self->springCleaningStats.lazyDeleteTime)
.detail("VacuumTime", self->springCleaningStats.vacuumTime);
lastReadsComplete = self->readsComplete;
lastWritesComplete = self->writesComplete;
}
}
void disableRateControl() {
if (dbFile && dbFile->getRateControl()) {
TraceEvent(SevDebug, "KeyValueStoreSQLiteShutdownRateControl").detail("Filename", dbFile->getFilename());
Reference<IRateControl> rc = dbFile->getRateControl();
dbFile->setRateControl({});
rc->wakeWaiters();
}
dbFile.clear();
if (walFile && walFile->getRateControl()) {
TraceEvent(SevDebug, "KeyValueStoreSQLiteShutdownRateControl").detail("Filename", walFile->getFilename());
Reference<IRateControl> rc = walFile->getRateControl();
walFile->setRateControl({});
rc->wakeWaiters();
}
walFile.clear();
}
ACTOR static Future<Void> stopOnError(KeyValueStoreSQLite* self) {
try {
wait(self->readThreads->getError() || self->writeThread->getError());
ASSERT(false);
} catch (Error& e) {
if (e.code() == error_code_actor_cancelled)
throw;
self->disableRateControl();
self->readThreads->stop(e).isReady();
self->writeThread->stop(e).isReady();
}
return Void();
}
ACTOR static void doClose(KeyValueStoreSQLite* self, bool deleteOnClose) {
state Error error = success();
self->disableRateControl();
try {
TraceEvent("KVClose", self->logID).detail("Filename", self->filename).detail("Del", deleteOnClose);
self->starting.cancel();
self->cleaning.cancel();
self->logging.cancel();
wait(self->readThreads->stop() && self->writeThread->stop());
if (deleteOnClose) {
wait(IAsyncFileSystem::filesystem()->incrementalDeleteFile(self->filename, true));
wait(IAsyncFileSystem::filesystem()->incrementalDeleteFile(self->filename + "-wal", false));
}
} catch (Error& e) {
TraceEvent(SevError, "KVDoCloseError", self->logID)
.detail("Filename", self->filename)
.error(e, true)
.detail("Reason", e.code() == error_code_platform_error ? "could not delete database" : "unknown");
error = e;
}
TraceEvent("KVClosed", self->logID).detail("Filename", self->filename);
if (error.code() != error_code_actor_cancelled) {
self->stopped.send(Void());
delete self;
}
}
};
IKeyValueStore* keyValueStoreSQLite(std::string const& filename,
UID logID,
KeyValueStoreType storeType,
bool checkChecksums,
bool checkIntegrity) {
return new KeyValueStoreSQLite(filename, logID, storeType, checkChecksums, checkIntegrity);
}
ACTOR Future<Void> cleanPeriodically(KeyValueStoreSQLite* self) {
wait(delayJittered(SERVER_KNOBS->SPRING_CLEANING_NO_ACTION_INTERVAL));
loop {
KeyValueStoreSQLite::SpringCleaningWorkPerformed workPerformed = wait(self->doClean());
double duration = std::numeric_limits<double>::max();
if (workPerformed.lazyDeletePages >= SERVER_KNOBS->SPRING_CLEANING_LAZY_DELETE_BATCH_SIZE) {
duration = std::min(duration, SERVER_KNOBS->SPRING_CLEANING_LAZY_DELETE_INTERVAL);
}
if (workPerformed.vacuumedPages > 0) {
duration = std::min(duration, SERVER_KNOBS->SPRING_CLEANING_VACUUM_INTERVAL);
}
if (duration == std::numeric_limits<double>::max()) {
duration = SERVER_KNOBS->SPRING_CLEANING_NO_ACTION_INTERVAL;
}
wait(delayJittered(duration));
}
}
ACTOR static Future<Void> startReadThreadsWhen(KeyValueStoreSQLite* kv, Future<Void> onReady, UID id) {
wait(onReady);
kv->startReadThreads();
return Void();
}
sqlite3_vfs* vfsAsync();
static int vfs_registered = 0;
KeyValueStoreSQLite::KeyValueStoreSQLite(std::string const& filename,
UID id,
KeyValueStoreType storeType,
bool checkChecksums,
bool checkIntegrity)
: type(storeType), logID(id), filename(filename), readThreads(CoroThreadPool::createThreadPool()),
writeThread(CoroThreadPool::createThreadPool()), readsRequested(0), writesRequested(0), writesComplete(0),
diskBytesUsed(0), freeListPages(0) {
TraceEvent(SevDebug, "KeyValueStoreSQLiteCreate").detail("Filename", filename);
stopOnErr = stopOnError(this);
#if SQLITE_THREADSAFE == 0
ASSERT(writeThread->isCoro());
#endif
if (!vfs_registered && writeThread->isCoro())
if (sqlite3_vfs_register(vfsAsync(), true) != SQLITE_OK)
ASSERT(false);
// The DB file should not already be open
ASSERT(!vfsAsyncIsOpen(filename));
ASSERT(!vfsAsyncIsOpen(filename + "-wal"));
readCursors.resize(SERVER_KNOBS->SQLITE_READER_THREADS); //< number of read threads
sqlite3_soft_heap_limit64(SERVER_KNOBS->SOFT_HEAP_LIMIT); // SOMEDAY: Is this a performance issue? Should we drop
// the cache sizes for individual threads?
TaskPriority taskId = g_network->getCurrentTask();
g_network->setCurrentTask(TaskPriority::DiskWrite);
writeThread->addThread(new Writer(this,
type == KeyValueStoreType::SSD_BTREE_V2,
checkChecksums,
checkIntegrity,
writesComplete,
springCleaningStats,
diskBytesUsed,
freeListPages,
id,
&readCursors));
g_network->setCurrentTask(taskId);
auto p = new Writer::InitAction();
auto f = p->result.getFuture();
writeThread->post(p);
starting = startReadThreadsWhen(this, f, logID);
cleaning = cleanPeriodically(this);
logging = logPeriodically(this);
}
KeyValueStoreSQLite::~KeyValueStoreSQLite() {
// printf("dbf=%lld bytes, wal=%lld bytes\n", getFileSize((filename+".fdb").c_str()),
// getFileSize((filename+".fdb-wal").c_str()));
}
StorageBytes KeyValueStoreSQLite::getStorageBytes() const {
int64_t free;
int64_t total;
g_network->getDiskBytes(parentDirectory(filename), free, total);
return StorageBytes(free, total, diskBytesUsed, free + _PAGE_SIZE * freeListPages);
}
void KeyValueStoreSQLite::startReadThreads() {
int nReadThreads = readCursors.size();
TaskPriority taskId = g_network->getCurrentTask();
g_network->setCurrentTask(TaskPriority::DiskRead);
for (int i = 0; i < nReadThreads; i++)
readThreads->addThread(
new Reader(filename, type == KeyValueStoreType::SSD_BTREE_V2, readsComplete, logID, &readCursors[i]));
g_network->setCurrentTask(taskId);
}
void KeyValueStoreSQLite::set(KeyValueRef keyValue, const Arena* arena) {
++writesRequested;
writeThread->post(new Writer::SetAction(keyValue));
}
void KeyValueStoreSQLite::clear(KeyRangeRef range, const Arena* arena) {
++writesRequested;
writeThread->post(new Writer::ClearAction(range));
}
Future<Void> KeyValueStoreSQLite::commit(bool sequential) {
++writesRequested;
auto p = new Writer::CommitAction;
auto f = p->result.getFuture();
writeThread->post(p);
return f;
}
Future<Optional<Value>> KeyValueStoreSQLite::readValue(KeyRef key, Optional<UID> debugID) {
++readsRequested;
auto p = new Reader::ReadValueAction(key, debugID);
auto f = p->result.getFuture();
readThreads->post(p);
return f;
}
Future<Optional<Value>> KeyValueStoreSQLite::readValuePrefix(KeyRef key, int maxLength, Optional<UID> debugID) {
++readsRequested;
auto p = new Reader::ReadValuePrefixAction(key, maxLength, debugID);
auto f = p->result.getFuture();
readThreads->post(p);
return f;
}
Future<RangeResult> KeyValueStoreSQLite::readRange(KeyRangeRef keys, int rowLimit, int byteLimit) {
++readsRequested;
auto p = new Reader::ReadRangeAction(keys, rowLimit, byteLimit);
auto f = p->result.getFuture();
readThreads->post(p);
return f;
}
Future<KeyValueStoreSQLite::SpringCleaningWorkPerformed> KeyValueStoreSQLite::doClean() {
++writesRequested;
auto p = new Writer::SpringCleaningAction;
auto f = p->result.getFuture();
writeThread->post(p);
return f;
}
void createTemplateDatabase() {
ASSERT(!vfs_registered);
SQLiteDB db1("template.fdb", false, false);
SQLiteDB db2("template.sqlite", true, true);
db1.createFromScratch();
db2.createFromScratch();
}
void GenerateIOLogChecksumFile(std::string filename) {
if (!fileExists(filename)) {
throw file_not_found();
}
FILE* f = fopen(filename.c_str(), "r");
FILE* fout = fopen((filename + ".checksums").c_str(), "w");
uint8_t buf[4096];
unsigned int c = 0;
while (fread(buf, 1, 4096, f) > 0)
fprintf(fout, "%u %u\n", c++, hashlittle(buf, 4096, 0xab12fd93));
fclose(f);
fclose(fout);
}
// If integrity is true, a full btree integrity check is done.
// If integrity is false, only a scan of all pages to validate their checksums is done.
ACTOR Future<Void> KVFileCheck(std::string filename, bool integrity) {
if (!fileExists(filename))
throw file_not_found();
StringRef kvFile(filename);
KeyValueStoreType type = KeyValueStoreType::END;
if (kvFile.endsWith(LiteralStringRef(".fdb")))
type = KeyValueStoreType::SSD_BTREE_V1;
else if (kvFile.endsWith(LiteralStringRef(".sqlite")))
type = KeyValueStoreType::SSD_BTREE_V2;
ASSERT(type != KeyValueStoreType::END);
state IKeyValueStore* store = keyValueStoreSQLite(filename, UID(0, 0), type, !integrity, integrity);
ASSERT(store != nullptr);
// Wait for integry check to finish
wait(success(store->readValue(StringRef())));
if (store->getError().isError())
wait(store->getError());
Future<Void> c = store->onClosed();
store->close();
wait(c);
return Void();
}