Re: autovacuum blues

On 09/11/06, Alvaro Herrera <alvherre(at)commandprompt(dot)com> wrote:
> Anton Melser wrote:
> > Hi,
> > I just can't understand why autovacuum is not working. I have a test
> > db/table which I insert values into (by the thousands) and can't work
> > out why my stats don't get updated. Could someone have a quick look at
> > my attached .conf and tell me what I am doing?
> > I am running it on FC5 8.1.4.fc5.1.
>
> You can tell whether autovacuum is running by using
>
> SHOW autovacuum;
>
>
> Note that if you have a firewall of some sort stopping UDP messages from
> being transmitted inside your machine, the stats collector may not
> start, which may stop the autovacuum daemon from starting. If you're
> not seeing stat updates then there's probably something like that going
> on. Maybe the system has emitted a warning message at server start;
> check the logs.

Thanks for that. Just a clarification, can someone tell me what the
"number of tuples" means in the context of the multipliers? I mean,
when the vacuum min multiplier is at 0.4, we multiply 0.4 by what? I
get the min val, but what are we multiplying by 0.4? The total number
of tuples in the table? The total modified/deleted?
I guess it is just that I assumed that it would kick in regularly, and
it doesn't seem to. Probably it is not needed but I always got the
feeling that after a good vacuum performance seemed better.
Cheers
Antoine