Re: Let PostgreSQL's On Schedule checkpoint write buffer smooth spread cycle by tuning IsCheckpointOnSchedule?

On 3 July 2015 at 06:38, Fabien COELHO <coelho(at)cri(dot)ensmp(dot)fr> wrote:

>
> Hello Simon,
>
> We could do better, but that is not a reason not to commit this, as is.
>> Commit, please.
>>
>
> My 0,02€: Please do not commit without further testing...
>
> I've submitted a patch to improve checkpoint write scheduling, including
> X00 hours of performance test on various cases. This patch changes
> significantly the load distribution over the whole checkpoint, and AFAICS
> has been tested on rather small cases.
>
> I'm not sure that the power 1.5 is the right one for all cases. For a big
> checkpoint over 30 minutes, it may have, or not, very large and possibly
> unwanted effects. Maybe the 1.5 factor should really be a guc. Well, what I
> really think is that it needs performance measures.
>

power 1,5 is almost certainly not right for all cases, but it is simple and
better. And easy to remove if something even better arrives.

I don't see the two patches being in conflict.

> In conclusion, and very egoistically, I would prefer if this patch could
> wait for the checkpoint scheduling patch to be considered, as it would
> basically invalidate the X00 hours of performance tests I ran:-)

I recommend making peace with yourself that probably 50% of development
time is wasted. But we try to keep the best half.

Thank you for your time spent contributing.

--
Simon Riggs http://www.2ndQuadrant.com/
<http://www.2ndquadrant.com/>
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