Re: checkpoint_timeout

Greg Stark wrote:
> Bruce Momjian <pgman(at)candle(dot)pha(dot)pa(dot)us> writes:
>
> > I don't see something that happens every five minutes as any kind of
> > performance problem. I am not sure what Josh saw that made him want to
> > increase that.
>
> I would have thought checkpoint_timeout would be something you would adjust
> depending on whether you want even performance (set it low and live with
> redundant i/o) or maximum throughput (set it high and live with i/o spikes and
> performance dropouts). Does that make sense?
>
> I suspect the origin of this meme might be with those benchmark graphs that
> were being posted here that had the checkpoint timeout set to 30m. That seems
> to be a bogus setting that's just hiding some of the i/o by postponing it
> until after the test ends.

Right, I can see shortening it before we had the trickle writer, but for
lengthening it, I don't see you are going to get that much improved
throughput.

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