Re: High SYS CPU - need advise - Mailing list pgsql-general

From Merlin Moncure
Subject Re: High SYS CPU - need advise
Date
Msg-id CAHyXU0zBGbUKnnE7KPSmNXinZZ47aL1yogOe1uCUduWjkzB06g@mail.gmail.com
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In response to Re: High SYS CPU - need advise  (Shaun Thomas <sthomas@optionshouse.com>)
Responses Re: High SYS CPU - need advise  (Shaun Thomas <sthomas@optionshouse.com>)
List pgsql-general
On Tue, Nov 20, 2012 at 10:12 AM, Shaun Thomas <sthomas@optionshouse.com> wrote:
> On 11/20/2012 10:03 AM, Merlin Moncure wrote:
>
>> Shared buffer manipulation changing contention is suggesting you're
>> running into free list lock issues.  How many active backends/cores?
>
>
> Oh, the reason I wanted to point it out was that we see a lot more than CPU
> contention with higher shared_buffer settings. The scheduler starts
> aggressively clearing out the file cache *and* freeing memory, driving load
> way higher than it should be. That doesn't result in a very high iowait, but
> all that page swapping sure isn't free.

have you ruled out numa issues?
(http://frosty-postgres.blogspot.com/2012/08/postgresql-numa-and-zone-reclaim-mode.html)

merlin


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