From 74eb2176bf3ac7a2fae1282b4f4f1d000f3e6d78 Mon Sep 17 00:00:00 2001 From: Peter Geoghegan Date: Thu, 4 Apr 2019 09:38:08 -0700 Subject: [PATCH] Invalidate binary search bounds consistently. _bt_check_unique() failed to invalidate binary search bounds in the event of a live conflict following commit e5adcb78. This resulted in problems after waiting for the conflicting xact to commit or abort. The subsequent call to _bt_check_unique() would restore the initial binary search bounds, rather than starting a new search. Fix by explicitly invalidating bounds when it becomes clear that there is a live conflict that insertion will have to wait to resolve. Ashutosh Sharma, with a few additional tweaks by me. Author: Ashutosh Sharma Reported-By: Ashutosh Sharma Diagnosed-By: Ashutosh Sharma Discussion: https://postgr.es/m/CAE9k0PnQp-qr-UYKMSCzdC2FBzdE4wKP41hZrZvvP26dKLonLg@mail.gmail.com --- src/backend/access/nbtree/nbtinsert.c | 8 +++++++- 1 file changed, 7 insertions(+), 1 deletion(-) diff --git a/src/backend/access/nbtree/nbtinsert.c b/src/backend/access/nbtree/nbtinsert.c index 96b7593fc1..4fda0efe9a 100644 --- a/src/backend/access/nbtree/nbtinsert.c +++ b/src/backend/access/nbtree/nbtinsert.c @@ -347,6 +347,7 @@ _bt_check_unique(Relation rel, BTInsertState insertstate, Relation heapRel, * This also saves the binary search bounds in insertstate. We use them * in the fastpath below, but also in the _bt_findinsertloc() call later. */ + Assert(!insertstate->bounds_valid); offset = _bt_binsrch_insert(rel, insertstate); /* @@ -447,7 +448,8 @@ _bt_check_unique(Relation rel, BTInsertState insertstate, Relation heapRel, * check, then don't bother checking if the tuple is being * updated in another transaction. Just return the fact * that it is a potential conflict and leave the full - * check till later. + * check till later. Don't invalidate binary search + * bounds. */ if (checkUnique == UNIQUE_CHECK_PARTIAL) { @@ -470,6 +472,8 @@ _bt_check_unique(Relation rel, BTInsertState insertstate, Relation heapRel, _bt_relbuf(rel, nbuf); /* Tell _bt_doinsert to wait... */ *speculativeToken = SnapshotDirty.speculativeToken; + /* Caller releases lock on buf immediately */ + insertstate->bounds_valid = false; return xwait; } @@ -526,6 +530,7 @@ _bt_check_unique(Relation rel, BTInsertState insertstate, Relation heapRel, _bt_relbuf(rel, nbuf); _bt_relbuf(rel, insertstate->buf); insertstate->buf = InvalidBuffer; + insertstate->bounds_valid = false; { Datum values[INDEX_MAX_KEYS]; @@ -601,6 +606,7 @@ _bt_check_unique(Relation rel, BTInsertState insertstate, Relation heapRel, } maxoff = PageGetMaxOffsetNumber(page); offset = P_FIRSTDATAKEY(opaque); + /* Don't invalidate binary search bounds */ } }