On Wed, 2025-05-21 at 16:34 +1200, Marcelo Fernandes wrote: > I am trying to understand if a stuck replication slot would be sufficient to > stop an autovacuum of even starting. > > Couldn't the autovacuum process start, but fail to remove dead tuples that > are still necessary by the replication slot? Why would it prevent autovacuum > of even starting instead?
I cannot think of a reason why an abandoned replication slot (not sure what you mean with "stuck") would keep an autovacuum worker from starting. Typical reasons why autovacuum doesn't start running on a table are: - there are already "autovacuum_max_workers" worker processes running - the thresholds for dead or inserted tuples have not been crossed - the statistics collector has a problem and doesn't gather statistics; this applies mostly to v14 and older, see https://www.cybertec-postgresql.com/en/stale-statistics-cause-table-bloat/ - the parameter "track_activities" was disabled, so that PostgreSQL doesn't collect statistics - the functions "pg_stat_reset" or "pg_stat_reset_single_table_counters" are called repeatedly and wipe out table statistics Yours, Laurenz Albe
