Followup Re: Performance question

OK, I seem to have fixed my own problem here again, sorry. I restarted
the postmaster, now _all_ queries are about 10x faster, and the first
execution on a new connection is no longer significantly slower than
the second. The server (and the original postmaster) had been up for:

11:18AM up 162 days, 17:48, 3 users, load averages: 0.57, 0.51, 0.51

Maybe I should have a cron script restart postmaster every now and
then, like once a week?

Bob

On Wednesday, Mar 5, 2003, at 10:11 US/Pacific, Bob Smith wrote:

>
> When I execute a query on a new connection, the performance is many
> times slower than if the query is repeated. In other words, if I
> start psql, execute the query, then repeat it immediately, the second
> time it takes only about 20% as long to execute. Now here's the
> confusing part, if I exit psql then start it up again, the same thing
> will occur on the new connection as well, the first execution takes 5x
> as long again. I don't understand this, it would make sense to me
> that the second execution being faster is due to disk caching on the
> server, but then why is it slower again on every new connection? Disk
> caching should benefit all current and new connections until the cache
> is flushed, which on this server shouldn't happen for a long time, the
> load is light and it has lots of RAM. Is Postgres doing some kind of
> caching itself that lasts only for the life of one backend process?
> If so, is there any way to make this caching persistent across
> backends?
>
> Server particulars:
>
> Postgres 7.2.1, Mac OS X Server 10.1.5, dual 1GHz CPUs, 1.5GB memory
>
> Thanks!
>
> Bob Smith
> Hammett & Edison, Inc.
> bsmith(at)h-e(dot)com
>
>
> ---------------------------(end of
> broadcast)---------------------------
> TIP 3: if posting/reading through Usenet, please send an appropriate
> subscribe-nomail command to majordomo(at)postgresql(dot)org so that your
> message can get through to the mailing list cleanly
>