| From: | Andres Freund <andres(at)anarazel(dot)de> |
|---|---|
| To: | Ashutosh Sharma <ashu(dot)coek88(at)gmail(dot)com>,Fabien COELHO <coelho(at)cri(dot)ensmp(dot)fr> |
| Cc: | Robert Haas <robertmhaas(at)gmail(dot)com>,Mithun Cy <mithun(dot)cy(at)enterprisedb(dot)com>,pgsql-hackers <pgsql-hackers(at)postgresql(dot)org>,Amit Kapila <amit(dot)kapila16(at)gmail(dot)com> |
| Subject: | Re: Perf Benchmarking and regression. |
| Date: | 2016-05-27 04:37:12 |
| Message-ID: | 3BD55B6E-A7B0-46E5-A684-9A76D7662515@anarazel.de |
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| Lists: | pgsql-hackers |
Hi,
On May 26, 2016 9:29:51 PM PDT, Ashutosh Sharma <ashu(dot)coek88(at)gmail(dot)com> wrote:
>Hi All,
>
>As we have seen the regression of more than 45% with
>"*backend_flush_after*"
>enabled and set to its default value i.e. 128KB or even when it is set
>to
>some higher value like 2MB, i think we should disable it such that it
>does
>not impact the read write performance and here is the attached patch
>for
>the same. Please have a look and let me know your thoughts on this.
>Thanks!
I don't think the situation is quite that simple. By *disabling* backend flushing it's also easy to see massive performance regressions. In situations where shared buffers was configured appropriately for the workload (not the case here IIRC).
Andres
--
Sent from my Android device with K-9 Mail. Please excuse my brevity.
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