Re: Problem with 8.4 stats collector high load

Jakub Ouhrabka wrote:
> > Maybe you should decrease naptime a bit.
>
> That did the trick, thanks!
>
> > Yes. There were some changes that needed to be done to autovacuum so
> > that it didn't read the stats file too often, but I don't recall if I
> > got around to it.
>
> I looked at the strace output and there are *writes* to the file not
> reads. Why? Is it a consequence of this optimization?
>
> Release notes 8.4:
>
> Reduce I/O load of writing the statistics collection file by writing
> the file only when requested (Martin Pihlak)
>
> Was autovacuum requesting to write this 20MB file 650x per minute?

Yes, exactly.

Ideally, autovacuum would only request a new copy of the file if the one
it got was considerably out of date. Obviously a tenth of a second is
not old enough.

--
Alvaro Herrera http://www.CommandPrompt.com/
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