Re: [PERFORM] PostgreSQL performance on a virtual host

2008-03-05 Thread Ivan Zolotukhin
Hello,

On Wed, Mar 5, 2008 at 5:40 PM, Bill Moran
<[EMAIL PROTECTED]> wrote:
> In response to "Ivan Zolotukhin" <[EMAIL PROTECTED]>:
>
> >
>  > We had a bad experience with PostgreSQL running in OpenVZ (year and a
>  > half year ago): OpenVZ kernel killed postmaster with strange signals
>  > from time to time, failcounters of OpenVZ did not worked as expected
>  > in this moments, PostgreSQL fighted for the disk with applications in
>  > other virtual cells, no one from OpenVZ forums was able to help me
>  > with these issues. So this experience was really dissapointing; since
>  > then we use only dedicated systems without kernels patched for
>  > virtualization.
>
>  If your database is busy enough that it's stressing the hardware on a
>  single machine, it's not going to do any better in a VM.  Sounds to me like
>  you were already pushing the limits of the IO capability of that machine ...
>  it's not OpenVZ's fault that it can't make more IO bandwidth available.

The problem actually was that PostgreSQL worked closely to some kernel
limits and kernel simply killed it sometimes without counting that in
corresponding failcounters. And there was no existing OpenVZ
documentation to debug these issues which I think is unacceptable.
Workload (incl. IO load) was moderate, nothing extremal.

I don't like when system kills my PostgreSQL without even telling me
why. Apart from that I think that administrator should be able to
decide himself whether load is high enough to stop some process for it
not to interfere with other virtual cells. OpenVZ with its
documentation and experts on dedicated forum did not provide such
instruments at that time. I would be satisfied with OpenVZ if I'd be
able to tell the system not to kill my PostgreSQL whatever happens,
but I couldn't. So I simply switched to something more reliable.

>  > On Wed, Mar 5, 2008 at 11:54 AM, Moritz Onken <[EMAIL PROTECTED]> wrote:
>  > > We have very good experiences with openVZ as virtualizer.
>  > >  Since it's not a para virtualization like xen it's very fast. Almost
>  > >  as fast as the host.
>  > >
>  > >  www.openvz.org
>  > >
>  > >  Am 04.03.2008 um 16:43 schrieb Theo Kramer:
>  > >
>  > >
>  > >
>  > >  > Hi
>  > >  >
>  > >  > We are thinking of running a PostgreSQL instance on a virtual host
>  > >  > under
>  > >  > Xen.
>  > >  >
>  > >  > Any thoughts for/against running PostgreSQL on a virtual host would be
>  > >  > much appreciated.
>  > >  >
>  > >  > --
>  > >  > Regards
>  > >  > Theo
>  > >  >
>  > >  >
>  > >  > --
>  > >  > Sent via pgsql-performance mailing list 
> (pgsql-performance@postgresql.org
>  > >  > )
>  > >  > To make changes to your Subscription:
>  > >  > 
> http://mail.postgresql.org/mj/mj_wwwusr?domain=postgresql.org&extra=pgsql-performance
>  > >
>  > >
>  > >  --
>  > >  Sent via pgsql-performance mailing list 
> (pgsql-performance@postgresql.org)
>  > >  To make changes to your subscription:
>  > >  
> http://mail.postgresql.org/mj/mj_wwwusr?domain=postgresql.org&extra=pgsql-performance
>  > >
>  >
>  > --
>  > Sent via pgsql-performance mailing list (pgsql-performance@postgresql.org)
>  > To make changes to your subscription:
>  > 
> http://mail.postgresql.org/mj/mj_wwwusr?domain=postgresql.org&extra=pgsql-performance
>
>
>  --
>  Bill Moran
>  Collaborative Fusion Inc.
>  http://people.collaborativefusion.com/~wmoran/
>
>  [EMAIL PROTECTED]
>  Phone: 412-422-3463x4023
>
>  
>  IMPORTANT: This message contains confidential information and is
>  intended only for the individual named. If the reader of this
>  message is not an intended recipient (or the individual
>  responsible for the delivery of this message to an intended
>  recipient), please be advised that any re-use, dissemination,
>  distribution or copying of this message is prohibited. Please
>  notify the sender immediately by e-mail if you have received
>  this e-mail by mistake and delete this e-mail from your system.
>  E-mail transmission cannot be guaranteed to be secure or
>  error-free as information could be intercepted, corrupted, lost,
>  destroyed, arrive late or incomplete, or contain viruses. The
>  sender therefore does not accept liability for any errors or
>  omissions in the contents of this message, which arise as a
>  result of e-mail transmission.
>  
>

--
Sent via pgsql-performance mailing list (pgsql-performance@postgresql.org)
To make changes to your subscription:
http://mail.postgresql.org/mj/mj_wwwusr?domain=postgresql.org&extra=pgsql-performance


Re: [PERFORM] PostgreSQL performance on a virtual host

2008-03-05 Thread Ivan Zolotukhin
Hello,

We had a bad experience with PostgreSQL running in OpenVZ (year and a
half year ago): OpenVZ kernel killed postmaster with strange signals
from time to time, failcounters of OpenVZ did not worked as expected
in this moments, PostgreSQL fighted for the disk with applications in
other virtual cells, no one from OpenVZ forums was able to help me
with these issues. So this experience was really dissapointing; since
then we use only dedicated systems without kernels patched for
virtualization.

--
Regards,
 Ivan

On Wed, Mar 5, 2008 at 11:54 AM, Moritz Onken <[EMAIL PROTECTED]> wrote:
> We have very good experiences with openVZ as virtualizer.
>  Since it's not a para virtualization like xen it's very fast. Almost
>  as fast as the host.
>
>  www.openvz.org
>
>  Am 04.03.2008 um 16:43 schrieb Theo Kramer:
>
>
>
>  > Hi
>  >
>  > We are thinking of running a PostgreSQL instance on a virtual host
>  > under
>  > Xen.
>  >
>  > Any thoughts for/against running PostgreSQL on a virtual host would be
>  > much appreciated.
>  >
>  > --
>  > Regards
>  > Theo
>  >
>  >
>  > --
>  > Sent via pgsql-performance mailing list (pgsql-performance@postgresql.org
>  > )
>  > To make changes to your Subscription:
>  > 
> http://mail.postgresql.org/mj/mj_wwwusr?domain=postgresql.org&extra=pgsql-performance
>
>
>  --
>  Sent via pgsql-performance mailing list (pgsql-performance@postgresql.org)
>  To make changes to your subscription:
>  
> http://mail.postgresql.org/mj/mj_wwwusr?domain=postgresql.org&extra=pgsql-performance
>

--
Sent via pgsql-performance mailing list (pgsql-performance@postgresql.org)
To make changes to your subscription:
http://mail.postgresql.org/mj/mj_wwwusr?domain=postgresql.org&extra=pgsql-performance


Re: [PERFORM] getting better performance

2006-07-06 Thread Ivan Zolotukhin

On 7/6/06, A. Kretschmer <[EMAIL PROTECTED]> wrote:

am  06.07.2006, um  9:40:16 +0300 mailte Eugeny N Dzhurinsky folgendes:
> In postgresql.conf I have these settings:
>
> shared_buffers = 4
> work_mem = 8192
> maintenance_work_mem = 16384
> max_stack_depth = 2048
>
> all other settings are left by default (except ones needed for pg_autovacuum).
>
> Is there anything I can tune to get better performance?

You can set "log_min_duration_statement" to log slow querys and then
analyse this querys.


When you collect your logs try PgFouine
http://pgfouine.projects.postgresql.org/
to understand what queries should be optimized and what's the reason
of poor performance.

---(end of broadcast)---
TIP 4: Have you searched our list archives?

  http://archives.postgresql.org


Re: [PERFORM] SQL CPU time usage

2006-05-18 Thread Ivan Zolotukhin

You may also try PgFouine (http://pgfouine.projects.postgresql.org/)
for log analysis, I found it very useful in similar situation.


On 5/17/06, Ruben Rubio Rey <[EMAIL PROTECTED]> wrote:

Hi,

I have a web page, that executes several SQLs.

So, I would like to know witch one of those SQLs consumes more CPU.
For example,
I have SQL1 that is executed in 1.2 secs and a SQL2 that is executed in
200 ms.

But SQL2 is executed 25 times and SQL1 is executed 1 time, so really
SQL2 consumes more CPU time.

Is there any way to know this?
I have think that logging all SQLs and then cheking it is a way to do it
... any other idea?

Thanks in advance

---(end of broadcast)---
TIP 2: Don't 'kill -9' the postmaster



---(end of broadcast)---
TIP 5: don't forget to increase your free space map settings