Re: Postgres 7.2.1 Really Spinning the CPU - Mailing list pgsql-general

That was my only general suggestion based on the general info that you had
just done an upgrade, So like Neil, I'd say that now we need to be getting
into particulars. Because the planner is very different it is not completely
surprising that you see a change in behavior, but you'll need to track it
down by looking at the specific queries that cause it.

One other "general" thought- The main thing that the planner does, when it
is working well is to reduce the I/O involved in obtaining the results. In a
busy system, this would tend to be reflected in slightly higher CPU usage,
since the CPU doesn't sit idle waiting for data as much as much. Have you
checked the performance in wall-clock-time to see if you're still getting
results in a reasonable (or shorter) length of time? You may find that the
"CPU spinning" is a good thing. If not, it's time to get specific.

-Nick

--------------------------------------------------------------------------
Nick Fankhauser  nickf@ontko.com  Phone 1.765.935.4283  Fax 1.765.962.9788
Ray Ontko & Co.     Software Consulting Services     http://www.ontko.com/


> -----Original Message-----
> From: pgsql-general-owner@postgresql.org
> [mailto:pgsql-general-owner@postgresql.org]On Behalf Of Hunter Hillegas
> Sent: Tuesday, June 04, 2002 10:21 PM
> To: Hunter Hillegas; nickf@ontko.com; PostgreSQL
> Subject: Re: [GENERAL] Postgres 7.2.1 Really Spinning the CPU
>
>
> Actually, I may have spoken too soon... It's now back to really
> spinning the
> CPU...
>
> Any other ideas?
>
>
>
> > From: Hunter Hillegas <lists@lastonepicked.com>
> > Date: Tue, 04 Jun 2002 20:03:29 -0700
> > To: <nickf@ontko.com>, PostgreSQL <pgsql-general@postgresql.org>
> > Subject: Re: [GENERAL] Postgres 7.2.1 Really Spinning the CPU
> >
> > I didn't. Now I have and it seems to have cleared it up.
> >
> >
> >> From: "Nick Fankhauser" <nickf@ontko.com>
> >> Reply-To: <nickf@ontko.com>
> >> Date: Tue, 4 Jun 2002 21:51:06 -0500
> >> To: "Hunter Hillegas" <lists@lastonepicked.com>, "PostgreSQL"
> >> <pgsql-general@postgresql.org>
> >> Subject: Re: [GENERAL] Postgres 7.2.1 Really Spinning the CPU
> >>
> >> Hunter-
> >>
> >> Have you done a vacuum analyze since the data reload? The stats are
> >> different enough that the planner gets all confused if you
> don't analyze
> >> right away.
> >>
> >> Regards,
> >>
> >> -Nick
> >>
> >>
> --------------------------------------------------------------------------
> >> Nick Fankhauser  nickf@ontko.com  Phone 1.765.935.4283  Fax
> 1.765.962.9788
> >> Ray Ontko & Co.     Software Consulting Services
> http://www.ontko.com/
> >>
> >>
> >>
> >>> -----Original Message-----
> >>> From: pgsql-general-owner@postgresql.org
> >>> [mailto:pgsql-general-owner@postgresql.org]On Behalf Of
> Hunter Hillegas
> >>> Sent: Tuesday, June 04, 2002 9:28 PM
> >>> To: PostgreSQL
> >>> Subject: [GENERAL] Postgres 7.2.1 Really Spinning the CPU
> >>>
> >>>
> >>> Just got my new server up and running with PostgreSQL 7.2.1... I
> >>> am running
> >>> Jive Forums against it.
> >>>
> >>> I used pg_dump to extract the data from the old server, and used 'psql
> >>> database < file.sql' to get the data into the new database.
> >>>
> >>> Now I have it up and running and PostgreSQL is using up to 40% of
> >>> the CPU...
> >>> My site is not heavily trafficked, so this seems out of place.
> >>>
> >>> Is it possible that Jive's indexes were not re-created
> properly? The old
> >>> server was also 7.2.1.
> >>>
> >>> I have bumped up shared memory:
> >>>
> >>> [root@vader init.d]# cat /proc/sys/kernel/shmmax
> >>> 128000000
> >>>
> >>> and in my postgresql.conf I have increased my shared buffers to 3000.
> >>>
> >>> Any ideas how to figure out what is going on?
> >>>
> >>> Thanks,
> >>> Hunter
> >>>
> >>>
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