Re: New to PostgreSQL, performance considerations

At 10:47 AM 12/12/2006, Tom Lane wrote:

>It's notoriously hard to get repeatable numbers out of pgbench :-(
That's not a good characteristic in bench marking SW...

Does the ODSL stuff  have an easier time getting reproducible results?


>A couple of tips:
>         * don't put any faith in short runs.  I usually use -t 1000
> plus -c whatever.
>         * make sure you loaded the database (pgbench -i) with a
> scale factor (-s) at least equal to the maximum -c you want to test.
>           Otherwise you're mostly measuring update contention.
>         * pay attention to when checkpoints occur.  You probably
> need to increase checkpoint_segments if you want pgbench not to be
> checkpoint-bound.
This all looks very useful.  Can you give some guidance as to what
checkpoint_segments should be increased to?   Do the values you are
running  pgbench with suggest what value checkpoint_segments should be?

Ron Peacetree