Re: Impact of checkpoint_segments under continual load conditions

Christopher Petrilli <petrilli(at)gmail(dot)com> writes:
> I have a unique scenerio. My DB is under "continual load", meaning
> that I am constantly using COPY to insert new data into the DB. There
> is no "quiet period" for the database, at least not for hours on end.
> Normally, checkpoint_segments can help absorb some of that, but my
> experience is that if I crank the number up, it simply delays the
> impact, and when it occurs, it takes a VERY long time (minutes) to
> clear.

If you are using 8.0, you can probably alleviate the problem by making
the bgwriter more aggressive. I don't have any immediate
recommendations for specific settings though.

A small checkpoint_segments setting is definitely bad news for
performance under heavy load.

regards, tom lane