Re: Strange behaviour under heavy load

hmm,

looks like checkpoint ?
Check checkpoint settings in postgresql.conf.

Oleg
On Tue, 27 Mar 2007, Dmitry Koterov wrote:

> Hello.
>
> I have found that sometimes heavy loaded PostgreSQL begins to run all the
> queries slower than usual, sometimes - 5 and more times slower. I cannot
> reprocude that, but symptoms are the following: queries work very fast for
> 5-10 minutes, and after that - significant slowdown (every query, even a
> simple one, works 5-10 and ever more times slower), disk write activity
> grows too (but not everytime - I don't know exactli if there is a direct
> correlation). 2-3 seconds, then - performance restores back to normal.
>
> Autovacuum is turned off.
>
> Machine has 2 processors, huge memory, fast SCSI disks.
>
> I understand that there is too less information. Please advice what to
> monitor for better problem discovering.
>

Regards,
Oleg
_____________________________________________________________
Oleg Bartunov, Research Scientist, Head of AstroNet (www.astronet.ru),
Sternberg Astronomical Institute, Moscow University, Russia
Internet: oleg(at)sai(dot)msu(dot)su, http://www.sai.msu.su/~megera/
phone: +007(495)939-16-83, +007(495)939-23-83