Re: pgstat wait timeout

On Thu, Dec 15, 2011 at 18:13, Tomas Vondra <tv(at)fuzzy(dot)cz> wrote:
> 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).

That was only true prior to 8.4. As of 8.4 it's only written when
necessary, which is usually a lot less than twice / second.

--
 Magnus Hagander
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