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help / color / mirror / Atom feedFrom: David Rowley <drowley@postgresql.org>
To: pgsql-committers@lists.postgresql.org
Subject: pgsql: Fix incorrect block accounting in TID Range Scans
Date: Wed, 23 Sep 2026 13:19:55 +0000
Message-ID: <E1x9Mt9-00000000vH1-0lUv@gemulon.postgresql.org> (raw)
Fix incorrect block accounting in TID Range Scans
heapgettup_advance_block() (or heapgettup() and heapgettup_pagemode() in
versions before v16) would incorrectly decrement rs_numblocks when
advancing to the next block. Ordinarily this was fine, but if the TID
Range scan plan was used by a scrollable cursor and the cursor was fetched
backwards enough to result in another block being required, then
rs_numblocks may have reached 0 prematurely resulting in the scan ending
prematurely.
Reported-by: Jeff Davis <pgsql@j-davis.com>
Author: Ewan Young <kdbase.hack@gmail.com>
Author: David Rowley <dgrowleyml@gmail.com>
Discussion: https://postgr.es/m/6b50233fcc0f7d6f4845f083777fa9702d9612e4.camel@j-davis.com
Backpatch-through: 14
Branch
------
REL_19_STABLE
Details
-------
https://git.postgresql.org/pg/commitdiff/ad230d58883b40bae3e5cc7bc04a80b8a790ee1a
Modified Files
--------------
src/backend/access/heap/heapam.c | 20 +++++++++++---------
src/test/regress/expected/tidrangescan.out | 26 ++++++++++++++++++++++++++
src/test/regress/sql/tidrangescan.sql | 12 ++++++++++++
3 files changed, 49 insertions(+), 9 deletions(-)
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To: pgsql-committers@postgresql.org
Cc: drowley@postgresql.org, pgsql-committers@lists.postgresql.org
Subject: Re: pgsql: Fix incorrect block accounting in TID Range Scans
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