Re: Performance degradation of inserts when database size grows

On Mon, May 23, 2011 at 2:46 PM, Tomas Vondra <tv@fuzzy.cz> wrote:
> Really? He already has 64 checkpoint segments, which is about 1GB of
> xlog data. The real problem is that the amount of buffers to write is
> constantly growing. At the beginning there's 62861 buffers (500MB) and
> at the end there's 137657 buffers (1GB).
>
> IMHO increasing the number of checkpoint segments would make this
> disruption even worse.

Maybe - but it would also make the checkpoints less frequent, which
might be a good thing.

> In 9.1 there's a feature that spreads checkpoint writes, but with 8.4
> that's not possible.

What feature are you referring to here?  Checkpoint spreading was
added in 8.3, IIRC.

--
Robert Haas
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