From: Heikki Linnakangas <heikki.linnakangas@iki.fi>
To: pgsql-committers@lists.postgresql.org
Subject: pgsql: Fix race condition in committing a serializable transaction
Date: Mon, 21 Oct 2024 08:01:19 +0000
Message-ID: <E1t2nLr-001jdR-GU@gemulon.postgresql.org> (raw)
Fix race condition in committing a serializable transaction
The finished transaction list can contain XIDs that are older than the
serializable global xmin. It's a short-lived state;
ClearOldPredicateLocks() removes any such transactions from the list,
and it's called whenever the global xmin advances. But if another
backend calls SummarizeOldestCommittedSxact() in that window, it will
call SerialAdd() on an XID that's older than the global xmin, or if
there are no more transactions running, when global xmin is
invalid. That trips the assertion in SerialAdd().
Fixes bug #18658 reported by Andrew Bille. Thanks to Alexander Lakhin
for analysis. Backpatch to all versions.
Discussion: https://www.postgresql.org/message-id/18658-7dab125ec688c70b%40postgresql.org
Branch
------
master
Details
-------
https://git.postgresql.org/pg/commitdiff/1a43de5e0a591b66ef3d92f3fac5aefcc2dc02fe
Modified Files
--------------
src/backend/storage/lmgr/predicate.c | 13 +++++++++----
1 file changed, 9 insertions(+), 4 deletions(-)
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To: pgsql-committers@postgresql.org
Cc: heikki.linnakangas@iki.fi, pgsql-committers@lists.postgresql.org
Subject: Re: pgsql: Fix race condition in committing a serializable transaction
In-Reply-To: <E1t2nLr-001jdR-GU@gemulon.postgresql.org>
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