Hello!
Autovacuum daemon performs vacuum when the number of rows
updated/deleted (n_dead_tuples) reaches some threshold.
Similarly it performs analyze when the number of rows changed in any way
(incl. inserted).
When a table is mostly insert-only, its visibility map is not updated as
vacuum threshold is almost never reached, but analyze does not update
visibility map.
Why could it be a bad idea to run vacuum after some number of any
changes including inserts, like analyze?
Or at least make it tunable by user (add a second bunch of paramters to
control second vacuum threshold, disabled by default)?
Best regards,
Alexey Bashtanov