Re: scheduler in core

Robert Haas <robertmhaas@gmail.com> writes:
> On Sun, Feb 21, 2010 at 10:17 AM, Lucas <lucas75@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.
        regards, tom lane