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Fix bugs in SSI tuple locking.

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1. In heap_hot_search_buffer(), the PredicateLockTuple() call is passed
wrong offset number. heapTuple->t_self is set to the tid of the first
tuple in the chain that's visited, not the one actually being read.

2. CheckForSerializableConflictIn() uses the tuple's t_ctid field
instead of t_self to check for exiting predicate locks on the tuple. If
the tuple was updated, but the updater rolled back, t_ctid points to the
aborted dead tuple.

Reported by Hannu Krosing. Backpatch to 9.1.
This commit is contained in:
Heikki Linnakangas 2013-10-07 23:57:40 +03:00
parent 0b109c822b
commit 81fbbfe335
2 changed files with 5 additions and 3 deletions
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4
src/backend/access/heap/heapam.c
View File

@ -1688,6 +1688,8 @@ heap_hot_search_buffer(ItemPointer tid, Relation relation, Buffer buffer,
at_chain_start = first_call; at_chain_start = first_call;
skip = !first_call; skip = !first_call;
heapTuple->t_self = *tid;
/* Scan through possible multiple members of HOT-chain */ /* Scan through possible multiple members of HOT-chain */
for (;;) for (;;)
{ {
@ -1717,7 +1719,7 @@ heap_hot_search_buffer(ItemPointer tid, Relation relation, Buffer buffer,
heapTuple->t_data = (HeapTupleHeader) PageGetItem(dp, lp); heapTuple->t_data = (HeapTupleHeader) PageGetItem(dp, lp);
heapTuple->t_len = ItemIdGetLength(lp); heapTuple->t_len = ItemIdGetLength(lp);
heapTuple->t_tableOid = RelationGetRelid(relation); heapTuple->t_tableOid = RelationGetRelid(relation);
heapTuple->t_self = *tid; ItemPointerSetOffsetNumber(&heapTuple->t_self, offnum);
/* /*
* Shouldn't see a HEAP_ONLY tuple at chain start. * Shouldn't see a HEAP_ONLY tuple at chain start.

4
src/backend/storage/lmgr/predicate.c
View File

@ -4279,8 +4279,8 @@ CheckForSerializableConflictIn(Relation relation, HeapTuple tuple,
SET_PREDICATELOCKTARGETTAG_TUPLE(targettag, SET_PREDICATELOCKTARGETTAG_TUPLE(targettag,
relation->rd_node.dbNode, relation->rd_node.dbNode,
relation->rd_id, relation->rd_id,
ItemPointerGetBlockNumber(&(tuple->t_data->t_ctid)), ItemPointerGetBlockNumber(&(tuple->t_self)),
ItemPointerGetOffsetNumber(&(tuple->t_data->t_ctid))); ItemPointerGetOffsetNumber(&(tuple->t_self)));
CheckTargetForConflictsIn(&targettag); CheckTargetForConflictsIn(&targettag);
} }