Re: checkpoint_timeout

[Julio Leyva <jcleyva@xxxxxxxxxxx>]

We have a transactional D.B writing directly to postgres (8.3) and these parameters have worked ok for us


checkpoint_timeout = 5min
checkpoint_segments = 10
wal_buffers = 1024kB

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Date: Wed, 8 Oct 2008 12:34:00 -0200
From: rafael.domiciano@xxxxxxxxx
To: bnichols@xxxxxxxxxxxxxxx
Subject: Re: [ADMIN] checkpoint_timeout
CC: chirag.dave@xxxxxxxxx; pgsql-admin@xxxxxxxxxxxxxx

Hello Brad,

All of my bgwriter parameters is set on default. Following:

#bgwriter_delay = 200ms                 # 10-10000ms between rounds

#bgwriter_lru_percent = 1.0             # 0-100% of LRU buffers scanned/round

#bgwriter_lru_maxpages = 5              # 0-1000 buffers max written/round

#bgwriter_all_percent = 0.333           # 0-100% of all buffers scanned/round

#bgwriter_all_maxpages = 5              # 0-1000 buffers max written/round

I am trying now to increase the checkpoint_segments to 40...

2008/10/8 Brad Nicholson <bnichols@xxxxxxxxxxxxxxx>

On Wed, 2008-10-08 at 10:31 -0200, Rafael Domiciano wrote:
> The server is running Postgres 8.2.4
> When the server is doing too much operations like I, U or D the
> postgres stop a while each 5 min...!
> I mean "stopping" that I don't receive any response from postgres, and
> the process the all people are running stay there, waiting for
> something.
> I read a several names to it like: gap, stall, slowdown... I don't
> know the write _expression_ for this situation.

The bgwriter was added to help alleviate this problem.

What are your settings for that?  The solution may be to push dirty
buffers to disk more aggressively via the bgwriter so you have less work
to do at checkpoint time.


--
Brad Nicholson  416-673-4106
Database Administrator, Afilias Canada Corp.