Re: [HACKERS] Autovacuum loose ends

On Sun, Jul 24, 2005 at 02:33:38PM -0400, Tom Lane wrote:
> Alvaro Herrera <alvherre(at)alvh(dot)no-ip(dot)org> writes:
> > - pg_statistic is completely ignored.
>
> ... pg_statistic still needs vacuuming, surely. It's only ANALYZE
> that you can/should skip for it.

Sorry, yes, it's ignored only for analyze.

> > - The postmaster's main loop sleeps Min(60, autovacuum_naptime), in
> > order to be able to pick naptimes smaller than 60 seconds. In order
> > not to make the loop a busy-wait, I forced a minimum of 1 to that GUC
> > var.
>
> Hmm, I wonder whether the minimum shouldn't be 10. Or even 60.

It's ok with me. What do other people think?

> > We have to consider what
> > happens at stat reset -- AFAICS there's no problem, because as soon as
> > the table sees some activity, it will be picked up by pgstat.
> > However, it would be bad if stats are reset right after some heavy
> > activity on a table. Maybe the only thing we need is documentation.
>
> What's the use-case for having the stat reset feature at all?

I don't know. Maybe the people who added it can tell?

> > - There are stat messages emitted for a database-wide vacuum, just like
> > any other. This means that all tables in the database would end up in
> > pgstat; and also all databases, including those with datallowconn = false.
> > This may not be good. I'm not sure what exactly to do about it. Do
> > we want to disallow such stats? Disable message sending (or
> > collecting) in some circumstances?
>
> Needs thought...

Ok.

--
Alvaro Herrera (<alvherre[a]alvh.no-ip.org>)
"I call it GNU/Linux. Except the GNU/ is silent." (Ben Reiter)