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References: <51F79AEC.3070103@audifarma.com.co>
Message-ID: <1375477408.36283.YahooMailNeo@web162901.mail.bf1.yahoo.com>
Date: Fri, 2 Aug 2013 14:03:28 -0700 (PDT)
From: Kevin Grittner <kgrittn@ymail.com>
Reply-To: Kevin Grittner <kgrittn@ymail.com>
Subject: Re: to many locks held
To: Jeison Bedoya <jeisonb@audifarma.com.co>,
 "pgsql-performance@postgresql.org" <pgsql-performance@postgresql.org>
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Jeison Bedoya <jeisonb@audifarma.com.co> wrote:

> memory ram: 128 GB
> cores: 32
>
> max_connections: 900

> temp_buffers =3D=A0 512MB

In addition to the other comments, be aware that temp_buffers is
the limit of how much RAM *each connection* can acquire to avoid
writing temporary table data to disk.=A0 Once allocated to a
connection, it will be reserved for that use on that connection
until the connection closes.=A0 So temp_buffers could lock down 450
GB of RAM even while all connections are idle.=A0 If the maximum
connections become active, and they average one work_mem allocation
apiece, that's an *additional* 900 GB of RAM which would be needed
to avoid problems.

Reducing connections through a pooler is strongly indicated, and
you may still need to reduce work_mem or temp_buffers.

http://wiki.postgresql.org/wiki/Number_Of_Database_Connections

--
Kevin Grittner
EDB: http://www.enterprisedb.com
The Enterprise PostgreSQL Company


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