Re: Tracking table modifications / table stats

On 3/3/2011 11:00 AM, Derrick Rice wrote:
> Hey folks,
>
> I was looking through the contrib modules with 8.4 and hoping to find
> something that satisfies my itch.
> http://www.postgresql.org/docs/8.4/static/pgstatstatements.html comes
> the closest.
>
> I'm inheriting a database which has mostly unknown usage patterns, and
> would like to figure them out so that I can allocate tablespaces and set
> autovacuum settings appropriately.  To do this, it seems I need to know
> (at least) the number of rows read, rows updated, rows deleted, and rows
> inserted for each table (over time, or until reset).
>
> I suppose things like disk usage and CPU usage would be interesting as
> well, but I'm somewhat less concerned with those.  For one, CPU usage
> can't be tied to a table as easily and is more about query optimization
> than PostgreSQL configuration (excluding cost coefficients and memory
> size settings).  For the other, disk usage can be mostly inferred from
> the row size and and number of operations per table (this does exclude
> seq. scans and heavy heavy index use, though).  I realize those
> statements are fuzzy and short-sighted, but I'm trying to get "good
> enough" information, not optimize a space shuttle.
>
> There's no way I'm the first person to feel the need for this.  Is there
> a doc or wiki which gives some recommendations?  I'd like to avoid
> parsing logs or installing triggers.  I'd also like to avoid heavy
> statement-level tracking like the above mentioned contrib does (sounds
> expensive, and I'm not sure the users have parameterized SQL).
>
> Thanks,
>
> Derrick

There are stat tables you can look at:

http://www.postgresql.org/docs/9.0/static/monitoring-stats.html

-Andy