Re: Vacuuming Questions

On Wed, 23 Apr 2008 16:27:33 +0100
John Gardner <john(dot)gardner(at)tagish(dot)co(dot)uk> wrote:

> We have two PostgreSQL servers (8.2) running in a cluster.

Could you be a bit more specific about what you mean by: in a cluster?

> Now, we're not seeing any problems with performance and we're not
> seeing any bloat but I have a couple of questions which I hope some
> of you can help me out on.
>
> 1) Is using the autovacuum daemon and running vacuumdb from a cron
> job overkill?

Not necessarily. Autovacuum can get behind when managing larger tables
that are actively used. This is better in 8.3 because you can have more
than one autovacuum worker.

>
> 2) The vendor of the clustering software suggests that I regularly
> run vacuum --all --analyze on a specific table. Surely, if I'm
> running vacuumdb --all --analyze isn't this just a wrapper for
> running the vacuum --all --analyze command anyway?

Well you have stated two different things here.

1. The vendor is stating you should vacuum a specific table
2. You are vacuuming the whole database.

Do you have a specific table that they are talking about? Is it
particularly busy? Say a session table?

> I guess that I'm
> asking why would I want to run vacuum --all --analyze on a specific
> table, when I regularly run vacuumdb --all --analyze on all databases?
>

Yes those two are identical.

Joshua D. Drake

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