Re: Checkpoint Tuning Question

On Wed, Jul 8, 2009 at 1:23 PM, Tom Lane<tgl(at)sss(dot)pgh(dot)pa(dot)us> wrote:
> Dan Armbrust <daniel(dot)armbrust(dot)list(at)gmail(dot)com> writes:
>> With checkpoint_segments set to 10, the checkpoints appear to be
>> happening due to checkpoint_timeout - which I've left at the default
>> of 5 minutes.
>
> Well, you could increase both those settings so as to put the
> checkpoints further apart, and/or increase checkpoint_completion_target
> to spread the checkpoint I/O over a larger fraction of the cycle.
>
>                        regards, tom lane
>

Sorry, didn't mean to get off list.

Wouldn't increasing the length between checkpoints result in the
checkpoint process taking even longer to complete?

The way my system processes and buffers incoming data, having
infrequent (but long and disruptive) checkpoints is bad, since it
causes the throughput to suffer so bad - my buffers can't hold the
flood, and I have to drop data. If I can reduce the impact of the
checkpoints, and have them occur more frequently, they my buffers
should be able to hold the incoming data during the short durations
that I have slow queries.

I'll go experiment with checkpoint_completion_target.

Thanks,

Dan