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authorThomas Munro <tmunro@postgresql.org>2019-06-28 11:11:26 +1200
committerThomas Munro <tmunro@postgresql.org>2019-06-28 17:15:39 +1200
commit6827e46cdf351678f71577efd4736f5d443b6e01 (patch)
tree03c5bf6198e2b16e7da44d81f70e00c356bf4621 /src/backend/executor/nodeIndexonlyscan.c
parent803cdf22a2d395653496702af789ccae7c17e18c (diff)
downloadpostgresql-6827e46cdf351678f71577efd4736f5d443b6e01.tar.gz
postgresql-6827e46cdf351678f71577efd4736f5d443b6e01.zip
Fix misleading comment in nodeIndexonlyscan.c.
The stated reason for acquiring predicate locks on heap pages hasn't existed since commit c01262a8, so fix the comment. Perhaps in a later release we'll also be able to change the code to use tuple locks. Back-patch all the way. Reviewed-by: Ashwin Agrawal Discussion: https://postgr.es/m/CAEepm%3D2GK3FVdnt5V3d%2Bh9njWipCv_fNL%3DwjxyUhzsF%3D0PcbNg%40mail.gmail.com
Diffstat (limited to 'src/backend/executor/nodeIndexonlyscan.c')
-rw-r--r--src/backend/executor/nodeIndexonlyscan.c7
1 files changed, 2 insertions, 5 deletions
diff --git a/src/backend/executor/nodeIndexonlyscan.c b/src/backend/executor/nodeIndexonlyscan.c
index 8c32a74d39e..7d2d50691e8 100644
--- a/src/backend/executor/nodeIndexonlyscan.c
+++ b/src/backend/executor/nodeIndexonlyscan.c
@@ -236,11 +236,8 @@ IndexOnlyNext(IndexOnlyScanState *node)
errmsg("lossy distance functions are not supported in index-only scans")));
/*
- * Predicate locks for index-only scans must be acquired at the page
- * level when the heap is not accessed, since tuple-level predicate
- * locks need the tuple's xmin value. If we had to visit the tuple
- * anyway, then we already have the tuple-level lock and can skip the
- * page lock.
+ * If we didn't access the heap, then we'll need to take a predicate
+ * lock explicitly, as if we had. For now we do that at page level.
*/
if (tuple == NULL)
PredicateLockPage(scandesc->heapRelation,