pgsql: Report syncscan position at end of scan. - Mailing list pgsql-committers

From Heikki Linnakangas
Subject pgsql: Report syncscan position at end of scan.
Date
Msg-id E1qbeeF-001nz1-SO@gemulon.postgresql.org
Whole thread Raw
List pgsql-committers
Report syncscan position at end of scan.

The comment in heapgettup_advance_block() says that it reports the
scan position before checking for end of scan, but that didn't match
the code. The code was refactored in commit 7ae0ab0ad9, which
inadvertently changed the order of the check and reporting. Change it
back.

This caused a few regression test failures with a small shared_buffers
setting like 10 MB. The 'portals' and 'cluster' tests perform seqscans
that are large enough that sync seqscans kick in. When the sync scan
position is not updated at end of scan, the next seq scan doesn't
start at the beginning of the table, and the test queries are
sensitive to that.

Reviewed-by: Melanie Plageman, David Rowley
Discussion: https://www.postgresql.org/message-id/6f991389-ae22-d844-a9d8-9aceb7c01a9a@iki.fi
Backpatch-through: 16

Branch
------
REL_16_STABLE

Details
-------
https://git.postgresql.org/pg/commitdiff/d5feb6011e629cc1096bbaa10af5ffcc6c17f908

Modified Files
--------------
src/backend/access/heap/heapam.c | 22 +++++++++++-----------
1 file changed, 11 insertions(+), 11 deletions(-)


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