| From: | Fabien COELHO <coelho(at)cri(dot)ensmp(dot)fr> |
|---|---|
| To: | Robert Haas <robertmhaas(at)gmail(dot)com> |
| Cc: | Amit Kapila <amit(dot)kapila16(at)gmail(dot)com>, Simon Riggs <simon(at)2ndquadrant(dot)com>, Heikki Linnakangas <hlinnaka(at)iki(dot)fi>, digoal zhou <digoal(dot)zhou(at)gmail(dot)com>, pgsql-hackers <pgsql-hackers(at)postgresql(dot)org> |
| Subject: | Re: Let PostgreSQL's On Schedule checkpoint write buffer smooth spread cycle by tuning IsCheckpointOnSchedule? |
| Date: | 2015-07-05 16:02:16 |
| Message-ID: | alpine.DEB.2.10.1507051751320.27775@sto |
| Views: | Raw Message | Whole Thread | Download mbox | Resend email |
| Thread: | |
| Lists: | pgsql-hackers |
> No, I'm not saying anyone *has* to do anything. What I'm saying is
> that I'm not convinced by your analysis.
Well, the gist of my analysis is really to say that there are potential
performance issues with the proposed change, and that it must be tested
thoroughly. The details may varry:-)
> I don't think we have enough evidence at this point to conclude that a
> GUC is necessary, and I hope it isn't, because I can't imagine what
> advice we would be able to give people about how to set it, other than
> "try all the value and see what works best", which isn't going to be
> satisfying.
At least for testing, ISTM that a GUC would be really useful.
> More broadly, I don't really know how to test this patch and show when
> it helps and when it hurts. And I think we need that, rather than just a
> theoretical analysis, to tune the behavior.
The point of an analysis is to think about how it works and what to test,
but it is not a substitute for testing, obviously.
--
Fabien.
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