WAL-log inplace update before revealing it to other sessions.
authorNoah Misch <[email protected]>
Fri, 25 Oct 2024 13:51:03 +0000 (06:51 -0700)
committerNoah Misch <[email protected]>
Fri, 25 Oct 2024 13:51:08 +0000 (06:51 -0700)
commite30d0d8adf534453355024aae68b8b691c105b67
treefd84b8cf379998a798e3cbc7820f641a7ae95f1d
parent4cf948cbeedffe597546af6c4a7a7e1d103c3923
WAL-log inplace update before revealing it to other sessions.

A buffer lock won't stop a reader having already checked tuple
visibility.  If a vac_update_datfrozenid() and then a crash happened
during inplace update of a relfrozenxid value, datfrozenxid could
overtake relfrozenxid.  That could lead to "could not access status of
transaction" errors.  Back-patch to v12 (all supported versions).  In
v14 and earlier, this also back-patches the assertion removal from
commit 7fcf2faf9c7dd473208fd6d5565f88d7f733782b.

Discussion: https://postgr.es/m/20240620012908[email protected]
src/backend/access/heap/README.tuplock
src/backend/access/heap/heapam.c
src/backend/access/transam/xloginsert.c