Re: Postgres is slow

Thanks guys.. I will try of the suggested steps. But one thing that I
do not understand that why should the performance deteriorate with
exactly same data with subsequent tests. And its juts gets worse as I
keep running it.

> also, the defaults in $PGDATA/postgresql.conf in 7.4 are *VERY* inefficient.
> there are a few key parameters that can make a significant difference in
> overall performance.
John, do you have any idea which parameters to change?

I tried similar tests also against PSQL 8.0 as well. But the results
are exactly same.

My final usage is going to be exteremly high. I would need something
like 1000 inserts/updates per sec. Do you think PSQL will scale?

Can the indexing on the byte array be one of the issue?

-Prajakt

On Tue, 08 Mar 2005 09:35:45 -0800, John R Pierce <pierce(at)hogranch(dot)com> wrote:
> >>I am using Postgres 7.4 on Fedora 3.0. It is running with the default
> >>configuration.
> ....
> > Probably this is not the right list for this.
> > Did you run vacuum after inserting the records?
> > Check your statement with explain analyze, it will show you why is it
> > slow.
>
> also, check serverlog in the data directory (/var/pgsql/data is the
> Redhat/Fedora default, I believe). If you're logging lots of errors, that file
> will grow, and they don't manage it.
>
> also, the defaults in $PGDATA/postgresql.conf in 7.4 are *VERY* inefficient.
> there are a few key parameters that can make a significant difference in
> overall performance.
>
> and, crontab (from the postgres user account) a vacuumdb every hour or so if
> you're doing lots of activity. once a day or week, do a vacuumdb -z to
> reindex stuff.
>
> and, shut postgres down, mv the $PGDATA directory to a different dedicated
> physical disk drive, and symlink it, then restart postgres.
>
> I've found that 7.x pgsql databases periodically need to be pg_dump'd, dropdb,
> then reloaded from the dump to continue to perform well... on a heavy use web
> server database which includes a busy user forum, I find doing this about 2-3
> times a year keeps things smooth. there may be a better way to clean them up,
> but I've not found it.
>
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