Re: PostgreSQL pgbench performance regression in 2.6.23+

Mike Galbraith
2008-05-22T07:10:24Z

On Wed, 2008-05-21 at 13:34 -0400, Greg Smith wrote:
> PostgreSQL ships with a simple database benchmarking tool named pgbench,
> in what's labeled the contrib section (in many distributions it's a
> separate package from the main server/client ones). I see there's been
> some work done already improving how the PostgreSQL server works under the
> new scheduler (the "Poor PostgreSQL scaling on Linux 2.6.25-rc5" thread).
> I wanted to provide you a different test case using pgbench that has taken
> a sharp dive starting with 2.6.23, and the server improvement changes in
> 2.6.25 actually made this problem worse.
>
> I think it will be easy for someone else to replicate my results and I'll
> go over the exact procedure below.

Yup, I can reproduce. Running the test with 2.6.25.4, everything is
waking/running on one CPU, leaving my box 75% idle. Not good.

-Mike