Re: new GUC var: autovacuum_process_all_tables

Alvaro Herrera <alvherre@commandprompt.com> writes:
> Right now, when autovacuum is turned on we always assume it's supposed
> to process all tables except those that have autovacuum_enabled=false.

> Now, sometimes it might make more sense to keep it enabled but have it
> only check for certain tables, and leave the majority of them disabled.

When would that be?  I can follow the use-case for vacuuming a selected
set of tables via cron-driven commands or whatever, and then excluding
those tables from autovacuum's purview.  But there isn't a command to
"vacuum all tables except these".  Without such a command available
to the cron-job, a switch such as you suggest is merely a foot-gun,
because it's dead certain some tables are going to get left out of
both manual and autovacuum processing.

And before anyone suggests it, I don't want to invent "vacuum all tables
except these".  It'd make more sense to put the effort into developing
better scheduling control over autovacuum, such as a concept of
maintenance windows.

(BTW, autovac does vacuum tables to prevent wraparound even if you try
to tell it to skip them, right?)
        regards, tom lane