Skip site navigation (1) Skip section navigation (2)

Re: Very high effective_cache_size == worse performance?

From: Scott Marlowe <scott(dot)marlowe(at)gmail(dot)com>
To: David Kerr <dmk(at)mr-paradox(dot)net>
Cc: pgsql-performance(at)postgresql(dot)org
Subject: Re: Very high effective_cache_size == worse performance?
Date: 2010-04-20 18:20:18
Message-ID: w2gdcc563d11004201120h88b16774ve81b22f60a875c9c@mail.gmail.com (view raw or flat)
Thread:
Lists: pgsql-performance
On Tue, Apr 20, 2010 at 12:15 PM, Scott Marlowe <scott(dot)marlowe(at)gmail(dot)com> wrote:
> On Tue, Apr 20, 2010 at 11:39 AM, David Kerr <dmk(at)mr-paradox(dot)net> wrote:
>> Howdy all,
>>
>> I've got a huge server running just postgres. It's got 48 cores and 256GB of ram. Redhat 5.4, Postgres 8.3.9.
>> 64bit OS. No users currently.
>
> What's your IO subsystem look like?  What did vmstat actually say?

Note that on a 48 core machine, if vmstat shows 2% wait and 98% idle
then you'd be 100% io bound, because it's % of total CPU.  iostat -x
10 will give a better view of how hard your disks are working, and if
they're the issue.

In response to

pgsql-performance by date

Next:From: David KerrDate: 2010-04-20 18:20:30
Subject: Re: Very high effective_cache_size == worse performance?
Previous:From: Kris JurkaDate: 2010-04-20 18:19:52
Subject: Re: Very high effective_cache_size == worse performance?

Privacy Policy | About PostgreSQL
Copyright © 1996-2014 The PostgreSQL Global Development Group