On Sun, Feb 21, 2010 at 1:05 PM, Tom Lane <t...@sss.pgh.pa.us> wrote: > Robert Haas <robertmh...@gmail.com> writes: >> On Sun, Feb 21, 2010 at 10:17 AM, Lucas <luca...@gmail.com> wrote: >>> I wonder if the scheduler already existed before the >>> implementation of the autovacuum, its implementation would >>> not be a function executed by the in-core scheduler? > >> The real genius of autovacuum is that it works out when there has been >> enough activity in particular tables that they need to be vacuumed. >> We might be able to use an in-core scheduler to wake it up every >> minute to look at the stats, or whatever it is that we do, but that's >> not all that exciting. > > The wake-up-every-N-seconds part of it is actually the weakest part > (search the archives for questions about autovacuum_naptime). To my > mind, the killer reason why autovac needed to be integrated is so that > the system itself could trigger autovac runs in response to threatened > XID wraparound conditions. A facility for scheduling user jobs, almost > by definition, won't have any system-internal trigger conditions.
Right. Without prejudice to my earlier statements that I think this might possibly be a good thing to do anyway, the case for it would be a lot stronger if it provided some genuine additional functionality. ...Robert -- Sent via pgsql-hackers mailing list (pgsql-hackers@postgresql.org) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-hackers
