Re: pgstat wait timeout

On 15 Prosinec 2011, 17:55, pratikchirania wrote:
> Hi,
>
> I am having a scenario where I get consistent warnings in the pglog
> folder:
>
> 2011-12-11 00:00:03 JST WARNING: pgstat wait timeout
> 2011-12-11 00:00:14 JST WARNING: pgstat wait timeout
> 2011-12-11 00:00:24 JST WARNING: pgstat wait timeout
> 2011-12-11 00:00:31 JST WARNING: pgstat wait timeout
> 2011-12-11 00:00:44 JST WARNING: pgstat wait timeout
> 2011-12-11 00:00:52 JST WARNING: pgstat wait timeout
> 2011-12-11 00:01:03 JST WARNING: pgstat wait timeout
> 2011-12-11 00:01:11 JST WARNING: pgstat wait timeout
>
> This is impacting database performance.

It's rather a sign that the I/O is overloaded, although in some cases it
may actually be the cause.

> The issue persists even when I use the database minimally.

Yes, because the file is written periodically - twice a second IIRC. If
the file is large, this may be an issue. What is the pgstat.stat size
(should be in data/global).

> I have tried fine-tuning the Auto-vacuum parameters:

Autovacuum has nothing to do with this.

> Any Ideas?

Move the file to a RAM drive - there's even a config parameter
'stats_temp_directory' to do that. See
http://www.postgresql.org/docs/9.1/static/runtime-config-statistics.html

Tomas