From 81fbbfe3352d3965ee3d8eaafe164b2335c43f72 Mon Sep 17 00:00:00 2001 From: Heikki Linnakangas Date: Mon, 7 Oct 2013 23:57:40 +0300 Subject: [PATCH] Fix bugs in SSI tuple locking. 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. --- src/backend/access/heap/heapam.c | 4 +++- src/backend/storage/lmgr/predicate.c | 4 ++-- 2 files changed, 5 insertions(+), 3 deletions(-) diff --git a/src/backend/access/heap/heapam.c b/src/backend/access/heap/heapam.c index ead3d690ae..a21f31b409 100644 --- a/src/backend/access/heap/heapam.c +++ b/src/backend/access/heap/heapam.c @@ -1688,6 +1688,8 @@ heap_hot_search_buffer(ItemPointer tid, Relation relation, Buffer buffer, at_chain_start = first_call; skip = !first_call; + heapTuple->t_self = *tid; + /* Scan through possible multiple members of HOT-chain */ for (;;) { @@ -1717,7 +1719,7 @@ heap_hot_search_buffer(ItemPointer tid, Relation relation, Buffer buffer, heapTuple->t_data = (HeapTupleHeader) PageGetItem(dp, lp); heapTuple->t_len = ItemIdGetLength(lp); heapTuple->t_tableOid = RelationGetRelid(relation); - heapTuple->t_self = *tid; + ItemPointerSetOffsetNumber(&heapTuple->t_self, offnum); /* * Shouldn't see a HEAP_ONLY tuple at chain start. diff --git a/src/backend/storage/lmgr/predicate.c b/src/backend/storage/lmgr/predicate.c index c0d369a431..a8a0e987a8 100644 --- a/src/backend/storage/lmgr/predicate.c +++ b/src/backend/storage/lmgr/predicate.c @@ -4279,8 +4279,8 @@ CheckForSerializableConflictIn(Relation relation, HeapTuple tuple, SET_PREDICATELOCKTARGETTAG_TUPLE(targettag, relation->rd_node.dbNode, relation->rd_id, - ItemPointerGetBlockNumber(&(tuple->t_data->t_ctid)), - ItemPointerGetOffsetNumber(&(tuple->t_data->t_ctid))); + ItemPointerGetBlockNumber(&(tuple->t_self)), + ItemPointerGetOffsetNumber(&(tuple->t_self))); CheckTargetForConflictsIn(&targettag); }