Hi!

> Indeed, the server log seems to indicate relationship to
> VACUUM:

> 2026-02-01 16:44:58.878 UTC autovacuum worker[22589] LOG:  automatic vacuum of table "postgres.pg_catalog.pg_class": index scans: 1

O, it's a good clue!

I have added some vacuum calls for pg_class in a stress test - and now it fails much more often (check attachment).

It is "ERROR:  cache lookup failed for relation" - but I think it may share the cause with "attempted to overwrite invisible tuple.

See:

https://cirrus-ci.com/build/4852126532239360 - with "Use multiple snapshots to copy the data."

https://cirrus-ci.com/build/6429084491710464 - with "Use background worker to do logical decoding."

But I am unable to reproduce the issue with only "Add CONCURRENTLY option to REPACK command."

Best regards,

Mikhail.