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Lots of postmaster processes  (fwd)
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* Lots of postmaster processes  (fwd)
@ 2005-12-13 17:25 Ameet Kini <akini@cs.wisc.edu>
  2005-12-16 21:56 ` Re: Lots of postmaster processes  (fwd) Jim C. Nasby <jnasby@pervasive.com>
  0 siblings, 1 reply; 2+ messages in thread

From: Ameet Kini @ 2005-12-13 17:25 UTC (permalink / raw)
  To: pgsql-performance



Resending it here as it may be more relevant here...
Ameet

---------- Forwarded message ----------
Date: Tue, 13 Dec 2005 11:24:26 -0600 (CST)
From: Ameet Kini <akini@cs.wisc.edu>
To: pgsql-admin@postgresql.org
Subject: Lots of postmaster processes



In our installation of the postgres 7.4.7, we are seeing a lot of the
following postmaster processes (around 50) being spawned by the initial
postmaster process once in a while:

postgres  3977     1  1 Nov03 ?        15:11:38
/s/postgresql-7.4.7/bin/postmaster -D /scratch.1/postgres/condor-db-7.4.7

......

postgres 31985  3977  0 10:08 ?        00:00:00
/s/postgresql-7.4.7/bin/postmaster -D /scratch.1/postgres/condor-db-7.4.7

postgres 31986  3977  0 10:08 ?        00:00:00
/s/postgresql-7.4.7/bin/postmaster -D /scratch.1/postgres/condor-db-7.4.7

postgres 31987  3977  0 10:08 ?        00:00:00
/s/postgresql-7.4.7/bin/postmaster -D /scratch.1/postgres/condor-db-7.4.7

postgres 31988  3977  0 10:08 ?        00:00:00
/s/postgresql-7.4.7/bin/postmaster -D /scratch.1/postgres/condor-db-7.4.7

......


At the same time when these processes being spawned, sometimes there is
also the checkpoint subprocess. I am not sure if that is related. The
document doesn't provide any information. The other activity going on at
the same time is a 'COPY' statement from a client application.

These extra processes put a considerable load on the machine and cause it
to hang up.

Thanks,
Ameet



^ permalink  raw  reply  [nested|flat] 2+ messages in thread

* Re: Lots of postmaster processes  (fwd)
  2005-12-13 17:25 Lots of postmaster processes  (fwd) Ameet Kini <akini@cs.wisc.edu>
@ 2005-12-16 21:56 ` Jim C. Nasby <jnasby@pervasive.com>
  0 siblings, 0 replies; 2+ messages in thread

From: Jim C. Nasby @ 2005-12-16 21:56 UTC (permalink / raw)
  To: Ameet Kini <akini@cs.wisc.edu>; +Cc: pgsql-performance

Dunno if this has gotten a reply elsewhere, but during a checkpoint the
database can become quite busy. If that happens and performance slows
down, other queries will slow down as well. If you have an app where a
a high rate of incomming requests (like a busy website), existing
backends won't be able to keep up with demand, so incomming connections
will end up spawning more connections to the database.

On Tue, Dec 13, 2005 at 11:25:40AM -0600, Ameet Kini wrote:
> 
> 
> Resending it here as it may be more relevant here...
> Ameet
> 
> ---------- Forwarded message ----------
> Date: Tue, 13 Dec 2005 11:24:26 -0600 (CST)
> From: Ameet Kini <akini@cs.wisc.edu>
> To: pgsql-admin@postgresql.org
> Subject: Lots of postmaster processes
> 
> 
> 
> In our installation of the postgres 7.4.7, we are seeing a lot of the
> following postmaster processes (around 50) being spawned by the initial
> postmaster process once in a while:
> 
> postgres  3977     1  1 Nov03 ?        15:11:38
> /s/postgresql-7.4.7/bin/postmaster -D /scratch.1/postgres/condor-db-7.4.7
> 
> ......
> 
> postgres 31985  3977  0 10:08 ?        00:00:00
> /s/postgresql-7.4.7/bin/postmaster -D /scratch.1/postgres/condor-db-7.4.7
> 
> postgres 31986  3977  0 10:08 ?        00:00:00
> /s/postgresql-7.4.7/bin/postmaster -D /scratch.1/postgres/condor-db-7.4.7
> 
> postgres 31987  3977  0 10:08 ?        00:00:00
> /s/postgresql-7.4.7/bin/postmaster -D /scratch.1/postgres/condor-db-7.4.7
> 
> postgres 31988  3977  0 10:08 ?        00:00:00
> /s/postgresql-7.4.7/bin/postmaster -D /scratch.1/postgres/condor-db-7.4.7
> 
> ......
> 
> 
> At the same time when these processes being spawned, sometimes there is
> also the checkpoint subprocess. I am not sure if that is related. The
> document doesn't provide any information. The other activity going on at
> the same time is a 'COPY' statement from a client application.
> 
> These extra processes put a considerable load on the machine and cause it
> to hang up.
> 
> Thanks,
> Ameet
> 
> ---------------------------(end of broadcast)---------------------------
> TIP 1: if posting/reading through Usenet, please send an appropriate
>        subscribe-nomail command to majordomo@postgresql.org so that your
>        message can get through to the mailing list cleanly
> 

-- 
Jim C. Nasby, Sr. Engineering Consultant      jnasby@pervasive.com
Pervasive Software      http://pervasive.com    work: 512-231-6117
vcard: http://jim.nasby.net/pervasive.vcf       cell: 512-569-9461



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