postgres.git / summary / log / commit / refs

commit    b8403d140f4e7d753d21116c0fa79dc4ca5ca5cb
Author:   Heikki Linnakangas <heikki.linnakangas@iki.fi>
Date:     Wed Jan 20 09:58:03 2021 +0000
First released in: 14.0, 12.6, 13.2

    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 79fe6eb8d62..1ea38d9b841 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))
 				{
 					/*


[parent: 31e0f9d76bb0]