The wal_buffers is 64Kb (The default)...
What Does wal_buffers do?
2008/10/8 Julio Leyva <jcleyva@xxxxxxxxxxx>
well it depends , our D.B is really high in transactions, and checkpoints_segments along with the wal_buffers are ok. you need to play with both of them
Date: Wed, 8 Oct 2008 14:19:37 -0200To: jcleyva@xxxxxxxxxxxCC: bnichols@xxxxxxxxxxxxxxx; chirag.dave@xxxxxxxxx; pgsql-admin@xxxxxxxxxxxxxx
Subject: Re: [ADMIN] checkpoint_timeoutHello Julio,If I set my postgresql server to checkpoint_segments = 10 aren't going to be poor segments?
2008/10/8 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
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@xxxxxxxxxxxxxxHello 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/roundI 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 bgwriter was added to help alleviate this problem.
> 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.
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.
