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!2331 合并PG pr：Fix predicate-locking of HOT updated rows 

Merge pull request !2331 from ab2020c/dev_predicate_locking
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opengauss-bot 2022-11-08 07:00:02 +00:00 committed by Gitee
parent 94b084b2cf 18639107af
commit dc3b2db447
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GPG Key ID: 173E9B9CA92EEF8F
1 changed files with 14 additions and 19 deletions
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33
src/gausskernel/storage/access/heap/heapam.cpp
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@ -2408,6 +2408,7 @@ bool heap_hot_search_buffer(ItemPointer tid, Relation relation, Buffer buffer, S
{
Page dp = (Page)BufferGetPage(buffer);
TransactionId prev_xmax = InvalidTransactionId;
BlockNumber blkno;
OffsetNumber offnum;
bool at_chain_start = false;
bool valid = false;
@ -2419,16 +2420,15 @@ bool heap_hot_search_buffer(ItemPointer tid, Relation relation, Buffer buffer, S
*all_dead = first_call;
}
Assert(TransactionIdIsValid(u_sess->utils_cxt.RecentGlobalXmin));
oldestXmin = GetOldestXminForHot(relation);
Assert(ItemPointerGetBlockNumber(tid) == BufferGetBlockNumber(buffer));
blkno = ItemPointerGetBlockNumber(tid);
offnum = ItemPointerGetOffsetNumber(tid);
at_chain_start = first_call;
skip = !first_call;
heap_tuple->t_self = *tid;
Assert(TransactionIdIsValid(u_sess->utils_cxt.RecentGlobalXmin));
oldestXmin = GetOldestXminForHot(relation);
Assert(BufferGetBlockNumber(buffer) == blkno);
HeapTupleCopyBaseFromPage(heap_tuple, dp);
/* Scan through possible multiple members of HOT-chain */
@ -2454,6 +2454,12 @@ bool heap_hot_search_buffer(ItemPointer tid, Relation relation, Buffer buffer, S
break;
}
/*
* Update heapTuple to point to the element of the HOT chain we're
* currently investigating. Having t_self set correctly is important
* because the SSI checks and the *Satisfies routine for historical
* MVCC snapshots need the correct tid to decide about the visibility.
*/
heap_tuple->t_data = (HeapTupleHeader)PageGetItem(dp, lp);
heap_tuple->t_len = ItemIdGetLength(lp);
heap_tuple->t_tableOid = RelationGetRelid(relation);
@ -2462,7 +2468,7 @@ bool heap_hot_search_buffer(ItemPointer tid, Relation relation, Buffer buffer, S
#ifdef PGXC
heap_tuple->t_xc_node_id = u_sess->pgxc_cxt.PGXCNodeIdentifier;
#endif
ItemPointerSetOffsetNumber(&heap_tuple->t_self, offnum);
ItemPointerSet(&heap_tuple->t_self, blkno, offnum);
/*
* Shouldn't see a HEAP_ONLY tuple at chain start.
@ -2487,14 +2493,6 @@ bool heap_hot_search_buffer(ItemPointer tid, Relation relation, Buffer buffer, S
* we skip it and return the next match we find.
*/
if (!skip) {
/*
* For the benefit of logical decoding, have t_self point at the
* element of the HOT chain we're currently investigating instead
* of the root tuple of the HOT chain. This is important because
* the *Satisfies routine for historical mvcc snapshots needs the
* correct tid to decide about the visibility in some cases.
*/
ItemPointerSet(&(heap_tuple->t_self), BufferGetBlockNumber(buffer), offnum);
/* If it's visible per the snapshot, we must return it */
valid = HeapTupleSatisfiesVisibility(heap_tuple, snapshot, buffer);
/* We unlock buffer if sync xid to finish and xid base may change, so copy base again */
@ -2515,9 +2513,6 @@ bool heap_hot_search_buffer(ItemPointer tid, Relation relation, Buffer buffer, S
ItemPointerGetOffsetNumber(&heap_tuple->t_data->t_ctid))));
}
/* reset to original, non-redirected, tid */
heap_tuple->t_self = *tid;
if (valid) {
ItemPointerSetOffsetNumber(tid, offnum);
PredicateLockTuple(relation, heap_tuple, snapshot);
@ -2554,7 +2549,7 @@ bool heap_hot_search_buffer(ItemPointer tid, Relation relation, Buffer buffer, S
* the next offnum and loop around.
*/
if (HeapTupleIsHotUpdated(heap_tuple)) {
Assert(ItemPointerGetBlockNumber(&heap_tuple->t_data->t_ctid) == ItemPointerGetBlockNumber(tid));
Assert(ItemPointerGetBlockNumber(&heap_tuple->t_data->t_ctid) == blkno);
offnum = ItemPointerGetOffsetNumber(&heap_tuple->t_data->t_ctid);
at_chain_start = false;
prev_xmax = HeapTupleGetUpdateXid(heap_tuple);