Re: Need for help!

Thank you for your answer!
*"You did not give CPU and disk info. But still 57 seems a small number.
What I guess is you're running pgbench with scale factor 1 (since you
haven't mentioned scale factor) and that causes extreme contention for
smaller tables with large number of clients."*

My CPU is 2CPU: Intel(R) Xeon(TM) CPU 3.20GHz. Disk: disk system is RAID-5;
OS CentOS. the number of scale in pgbench initialization is 100. It will be
generate 10 000 000 rows in the accounts table. Fill factor is default.
In the other way, I heard that: PostgreSQL working with RAID-10 better than
RAID-5 is it right?

* "Regarding maximum number of clients, check your "max_connections"
setting."
*
I set max_connections is 200. *
*
57 seems a small number, according to you, how much tps is normal or fast?
and what is the different of "shared_buffers" and "effective_cache_size".

Thank you once more!
Regards,
Semi Noob

2008/5/15 Pavan Deolasee <pavan(dot)deolasee(at)gmail(dot)com>:

> On Tue, May 13, 2008 at 2:43 PM, Semi Noob <seminoob(at)gmail(dot)com> wrote:
> > But after upgrade the max clients is
> > also 64 (?!?) Is this the maximum clients support by program pgbench (my
> > server on Linux ver8.2.5, pgbench on Windows - version postgresql is
> 8.3.1)?
> > And the number 57 tps is fast?
> >
>
> You did not give CPU and disk info. But still 57 seems a small number.
> What I guess is you're running pgbench with scale factor 1 (since you
> haven't mentioned scale factor) and that causes extreme contention for
> smaller tables with large number of clients.
>
> Regarding maximum number of clients, check your "max_connections" setting.
>
> > Another questions, i heard that PostgreSQL does not support HT
> Technology,
> > is it right?
> >
>
> I'm not sure what do you mean by HT, but if it's hyper threading, then
> IMO that statement is not completely true. Postgres is not
> multi-threaded, so a single process (or connection) may not be able to
> use all the CPUs, but as long as there are multiple connections (each
> connection corresponds to one backend process), as many CPUs will be
> used.
>
> > Last question, i don't understand so much the shmmax, shared_buffers,
> after
> > upgrading my server from 4 GB RAM to 8 GB RAM, first i configure shmmax
> to
> > 2GB, share_buffers to 1GB and start server, it runs, after that i set
> shmmax
> > to 4GB and restart, it fails (?!?). The error logs said that not enough
> > share memory! and final i set shmmax to 3GB and share buffer to 2GB, it
> > runs. Don't know why, can you explain?
>
> That doesn't make sense. I am guessing that you are running a 32 bit
> OS. 4GB of shmmax won't work on a 32 bit OS.
>
> Thanks,
> Pavan
>
> Pavan Deolasee
> EnterpriseDB http://www.enterprisedb.com
>