Re: [NOVICE] Fwd: Process scheduling in postgres

On Fri, Apr 22, 2016 at 5:21 PM raghu vineel <raghuvineel(at)gmail(dot)com> wrote:

>
> Hi,
>
> I have a 4 core CPU for postgres and I have submitted 6 queries parallely
> in 6 different sessions. But I am seeing only 1 query per CPU and the
> remainig queries are queued. I am not sure why is it happening. Do you have
> any special scheduler for postgres? I can see that CPU has been shared with
> other non postgres processes but postgres processes are not sharing any CPU
> within a core. The following is the process states.
>
>
> *lms 2868 2209 98 07:20 ? 00:02:30 postgres: lms controller
> [local] SELECTlms 2869 2209 98 07:20 ? 00:02:30 postgres: lms
> controller [local] SELECT*
> lms 2870 2209 0 07:20 ? 00:00:00 postgres: lms controller
> [local] SELECT
> lms 2871 2209 0 07:20 ? 00:00:00 postgres: lms controller
> [local] SELECT
> lms 2872 2209 0 07:20 ? 00:00:00 postgres: lms controller
> [local] SELECT
> *lms 2873 2209 98 07:20 ? 00:02:30 postgres: lms controller
> [local] SELECT*
>
> If you see above, three Select queries have been queued. They are
> acquiring CPU only when there is a core without any postgres query running
> on it.
>
> I know the postgres limitation of one query using only one core. But is
> there any limitation of one CPU running only one query at a time?
>
>
Are all the queries related to the same table(s)?
Which version of PostgreSQL? What's the version of OS?

Check out the locks which are not granted yet - pg_locks.granted

> Your help is appreciated.
>
> Thanks and regards,
> Vineel.
>
> --
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