Re: Vacuuming Questions

["Scott Marlowe" <scott(dot)marlowe(at)gmail(dot)com>]

On Wed, Apr 23, 2008 at 9:27 AM, John Gardner <john(dot)gardner(at)tagish(dot)co(dot)uk> wrote:
> We have two PostgreSQL servers (8.2) running in a cluster.
>
>  We have autovacuum switched on on both servers and also we are running the
> following as a cron job;
>
>  Server 1:
>  30 0,2,4,6,8,10,12,14,16,18,20,22 * * * /usr/bin/vacuumdb --all --analyze

You can change that to

30 0-59/2 * * * ...
and
30 1-59/2 * * *

(I think the second one does the odd minutes.  might need to test it.

>  1) Is using the autovacuum daemon and running vacuumdb from a cron job
> overkill?

Maybe.  It's probably better let autovacuum handle most of the db, and
use a single vacuum analyze on the one really busy table.

It's possible that you're using up too much of your I/O bandwidth
cleaning a bunch of table that don't need it.   As Joshua mentioned,
it's probably a good idea to look at 8.3 due to its ability to run >1
autovacuum thread at a time.