Re: Autovacuum and visibility maps - Mailing list pgsql-general

I have to believe it is due to this:

https://www.postgresql.org/docs/current/routine-vacuuming.html#VACUUM-FOR-SPACE-RECOVERY

"If you have a table whose entire contents are deleted on a periodic
basis, consider doing it with TRUNCATE rather than using DELETE followed
by VACUUM. TRUNCATE removes the entire content of the table immediately,
without requiring a subsequent VACUUM or VACUUM FULL to reclaim the
now-unused disk space. The disadvantage is that strict MVCC semantics
are violated."

Combined with this:

https://www.postgresql.org/docs/current/runtime-config-autovacuum.html#GUC-AUTOVACUUM-VACUUM-INSERT-THRESHOLD

"autovacuum_vacuum_threshold

Specifies the minimum number of updated or deleted tuples needed to
trigger a VACUUM in any one table. ...

"

I'm going to say the TRUNCATE itself does not trigger an autovacuum. I
would suggest throwing a manual VACUUM in the table population script.