Fix setting next multixid's offset at offset wraparound

Heikki Linnakangas <heikki.linnakangas@iki.fi>

Commit: 02ba5e3be4f3520a45f3c9c22f61d62c4eadbb76
Author: Heikki Linnakangas <heikki.linnakangas@iki.fi>
Date: 2025-12-05T09:35:20Z
Releases: 18.2
Fix setting next multixid's offset at offset wraparound

In commit 789d65364c, we started updating the next multixid's offset
too when recording a multixid, so that it can always be used to
calculate the number of members. I got it wrong at offset wraparound:
we need to skip over offset 0. Fix that.

Discussion: https://www.postgresql.org/message-id/d9996478-389a-4340-8735-bfad456b313c@iki.fi
Backpatch-through: 14

Files

PathChange+/−
src/backend/access/transam/multixact.c modified +7 −2

Discussion