From b8403d140f4e7d753d21116c0fa79dc4ca5ca5cb Mon Sep 17 00:00:00 2001 From: Heikki Linnakangas Date: Wed, 20 Jan 2021 11:58:03 +0200 Subject: [PATCH] Fix bug in detecting concurrent page splits in GiST insert In commit 9eb5607e699, I got the condition on checking for split or deleted page wrong: I used && instead of ||. The comment correctly said "concurrent split _or_ deletion". As a result, GiST insertion could miss a concurrent split, and insert to wrong page. Duncan Sands demonstrated this with a test script that did a lot of concurrent inserts. Backpatch to v12, where this was introduced. REINDEX is required to fix indexes that were affected by this bug. Backpatch-through: 12 Reported-by: Duncan Sands Discussion: https://www.postgresql.org/message-id/a9690483-6c6c-3c82-c8ba-dc1a40848f11%40deepbluecap.com --- src/backend/access/gist/gist.c | 5 ++++- 1 file changed, 4 insertions(+), 1 deletion(-) diff --git a/src/backend/access/gist/gist.c b/src/backend/access/gist/gist.c index 79fe6eb8d6..1ea38d9b84 100644 --- a/src/backend/access/gist/gist.c +++ b/src/backend/access/gist/gist.c @@ -246,6 +246,9 @@ gistplacetopage(Relation rel, Size freespace, GISTSTATE *giststate, if (GistFollowRight(page)) elog(ERROR, "concurrent GiST page split was incomplete"); + /* should never try to insert to a deleted page */ + Assert(!GistPageIsDeleted(page)); + *splitinfo = NIL; /* @@ -861,7 +864,7 @@ gistdoinsert(Relation r, IndexTuple itup, Size freespace, */ } else if ((GistFollowRight(stack->page) || - stack->parent->lsn < GistPageGetNSN(stack->page)) && + stack->parent->lsn < GistPageGetNSN(stack->page)) || GistPageIsDeleted(stack->page)) { /*