(2013/11/18 11:25), Claudio Freire wrote:
On Sun, Nov 17, 2013 at 11:02 PM, KONDO Mitsumasa
<kondo.mitsum...@lab.ntt.co.jp> wrote:
However, my patch is on the way and needed to more improvement. I am
going
to add method of controlling readahead by GUC, for user can freely select
readahed parameter in their transactions.
Rather, I'd try to avoid fadvising consecutive or almost-consecutive
blocks. Detecting that is hard at the block level, but maybe you can
tie that detection into the planner, and specify a sequential strategy
when the planner expects index-heap correlation?
I think we had better to develop these patches in step by step each patches,
because it is difficult that readahead optimizetion is completely come true
from a beginning of one patch. We need flame-work in these patches, first.
Well, problem is, that without those smarts, I don't think this patch
can be enabled by default. It will considerably hurt common use cases
for postgres.
Yes. I have thought as much you that defalut setting is false.
(use normal readahead as before). Next version of my patch will become these.
But I guess we'll have a better idea about that when we see how much
of a performance impact it makes when you run those tests, so no need
to guess in the dark.
Yes, sure.
Regards,
--
Mitsumasa KONDO
NTT Open Source Software Center
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