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Re: Shared_buffers hint

From: Marcelo Martins <pglists(at)zeroaccess(dot)org>
To: Rafael Domiciano <rafael(dot)domiciano(at)gmail(dot)com>
Cc: "pgsql-admin(at)postgresql(dot)org" <pgsql-admin(at)postgresql(dot)org>
Subject: Re: Shared_buffers hint
Date: 2008-10-06 13:23:13
Message-ID: 1538D014-0A5A-4DC1-928A-446E8A783267@zeroaccess.org (view raw or flat)
Thread:
Lists: pgsql-admin
Hi Rafael,

The result there means that the minimal should be 4.69Mb for  
shared_buffers
As a rule of thumb the shared buffers should be between 10% - 15% of  
available RAM that assuming such is a dedicated PG server.
I have worked on some servers where I set shared buffers lower than  
10%,  it's really a matter of trying out what value works best for  you.


Marcelo
Linux/Solaris System Administrator
http://www.zeroaccess.org

On Oct 6, 2008, at 6:52 AM, Rafael Domiciano wrote:

> HI people,
>
> I'm tuning a server that is a long time abandoned, and this server  
> is a little slow.
> Now, in my postgresql.conf I have:
> shared_buffers = 100Mb
> mas_fsm_relations = 15000
> mas_fsm_pages = 1600000
> max_connections = 300
>
> And I changin' to:
> shared_buffers = 1000Mb
>    (The server has 2 Gb of memory)
> mas_fsm_relations = 15000
>    (The Vacuum noticed me 608 relations)
> mas_fsm_pages = 1600000
>    (The Vacuum noticed me 500800 pages)
> max_connections = 300
>    (I did a "ps axf | grep postgres | wc -l" and the bash brings to  
> me the number of 120 and all the people is not online at now)
>
> My qustion is about shared_buffers, in postgresql.conf I have: min  
> 128kB or max_connections*16kB  # (change requires restart)
> So I did:
> 300 * (16Kb / 1024) = 4,69?
> What this result means?
>
> Thnks all,
>
> Rafael Domiciano

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Subject: Re: Shared_buffers hint
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