Re: PostgreSQL and sql-bench

On Thu, Sep 21, 2006 at 11:12:45AM -0400, Tom Lane wrote:
> yoav x <yoav112003(at)yahoo(dot)com> writes:
> > I've applied the following parameters to postgres.conf:
>
> > max_connections = 500
> > shared_buffers = 3000
> > work_mem = 100000
> > effective_cache_size = 3000000000

You just told the database that you have 23G of storage.
effective_cache_size is measured in blocks, which are normally 8K.

> Please see my earlier reply --- you ignored at least
> checkpoint_segments, which is critical, and perhaps other things.
>
> Don't forget also that testing mysql/myisam against fsync = on
> is inherently unfair.

Even with fsync = off, there's still a non-trivial amount of overhead
brought on by MVCC that's missing in myisam. If you don't care about
concurrency or ACIDity, but performance is critical (the case that the
MySQL benchmark favors), then PostgreSQL probably isn't for you.
--
Jim Nasby jim(at)nasby(dot)net
EnterpriseDB http://enterprisedb.com 512.569.9461 (cell)