Data corruption: checkpoint can lose a multixact created during its start
Hackorum builds and tests every patch posted to the lists, not only commitfest submissions. This is Hackorum's own CI rather than the PostgreSQL project's, and it is still under testing - please report anything that looks wrong.
You can run a PostgreSQL built from this patch straight from Docker, with no checkout and no build:
docker run --rm -p 5432:5432 ghcr.io/hackorum-dev/postgres-patch:t254452psql -h localhost -U postgresBuilt from patchset v1 (message #1), November 02, 2026 at 03:26 AM.
Every patchset is also pushed to a branch of our PostgreSQL fork, so you can check out the same tree CI built. Without a PostgreSQL checkout:
git clone --branch t254452_1 https://github.com/hackorum-dev/postgres.gitIn a checkout you already have, add the fork once:
git remote add hackorum https://github.com/hackorum-dev/postgres.gitthen, for this patchset and every later one:
git fetch hackorum t254452_1 && git checkout t254452_1Patchset v1 (message #1) is on t254452_1
Hi,
MultiXactIdCreateFromMembers() inserts the CREATE_ID record before it
fills the SLRU pages. A checkpoint can take its redo pointer in between
and flush the pages first. After a crash, recovery starts after passing the
record and
the multixact has no members. In a non-assert build the old row version
becomes visible again next to the new one.
0001 sets DELAY_CHKPT_START around the two steps, like
TruncateMultiXact(). 0002 is the repro.
0001 applies to 15 and up. 14 needs the old delayChkpt flag. The test
needs 18 and up.
Thanks,
Shihao