| From: | Merlin Moncure <mmoncure(at)gmail(dot)com> |
|---|---|
| To: | sthomas(at)optionshouse(dot)com |
| Cc: | Vlad <marchenko(at)gmail(dot)com>, Jeff Janes <jeff(dot)janes(at)gmail(dot)com>, Alvaro Herrera <alvherre(at)2ndquadrant(dot)com>, pgsql-general(at)postgresql(dot)org |
| Subject: | Re: High SYS CPU - need advise |
| Date: | 2012-11-20 16:13:57 |
| Message-ID: | CAHyXU0zBGbUKnnE7KPSmNXinZZ47aL1yogOe1uCUduWjkzB06g@mail.gmail.com |
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| Lists: | pgsql-general |
On Tue, Nov 20, 2012 at 10:12 AM, Shaun Thomas <sthomas(at)optionshouse(dot)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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