Re: checkpoint_timeout - Mailing list pgsql-admin

From Kevin Grittner
Subject Re: checkpoint_timeout
Date
Msg-id 48ECB0DD.EE98.0025.0@wicourts.gov
Whole thread Raw
In response to Re: checkpoint_timeout  ("Rafael Domiciano" <rafael.domiciano@gmail.com>)
Responses Re: checkpoint_timeout  ("Scott Marlowe" <scott.marlowe@gmail.com>)
List pgsql-admin
>>> "Rafael Domiciano" <rafael.domiciano@gmail.com> wrote:
> Right...I going to restart my server only tonight, the access along
the day
> is too much to do now...!
> Maybe increasing a little bit could do difference?
> I thougth to increase to around 256 Kb!
> I have a doubt... what's the chance to my server get instable?

Changing wal_buffers to that isn't at all likely to cause problems,
unless you are teetering right on the edge of exceeding your shmmax
setting.  It's also unlikely to help much, in my opinion.

If the problem is checkpoints (which seems likely but far from a sure
thing based on the information provided), aggressive background writer
setting might be your best bet under 8.2.X.  To solve similar problems
we had to go to the following, although many on these lists feel that
settings this aggressive are rarely needed, so use at your own risk.

#bgwriter_delay = 200ms
bgwriter_lru_percent = 20.0
bgwriter_lru_maxpages = 200
bgwriter_all_percent = 10.0
bgwriter_all_maxpages = 600

Even better would be to go to the latest revision of the 8.3 release,
which at this writing is 8.3.4.  In that release PostgreSQL spreads
out the work of a checkpoint to minimize this problem.

-Kevin

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