Date: Wed, 5 Aug 2015 17:24:48 +0000 (UTC)
From: Kevin Grittner <kgrittn@ymail.com>
Reply-To: Kevin Grittner <kgrittn@ymail.com>
To: Alexandre de Arruda Paes <adaldeia@gmail.com>,
 "pgsql-performance@postgresql.org" <pgsql-performance@postgresql.org>
Message-ID: <294645189.286929.1438795488655.JavaMail.yahoo@mail.yahoo.com>
In-Reply-To: 
 <CAGewt-tbqRW5NLAzKDCvP_ztEN_LMMyGugQ1iVVEzB+p2XpefQ@mail.gmail.com>
References: 
 <CAGewt-tbqRW5NLAzKDCvP_ztEN_LMMyGugQ1iVVEzB+p2XpefQ@mail.gmail.com>
Subject: Re: Slow HashAggregate/cache access
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 7bit
Content-Length: 1164
Precedence: bulk
Sender: pgsql-performance-owner@postgresql.org

Alexandre de Arruda Paes <adaldeia@gmail.com> wrote:

> We did the following tests:
>
> 1) Postgresql 9.3 and Oracle 10 in a desktop machine(8 GB RAM, 1 SATA disk,Core i5)
> 2) Postgresql 9.3 in a server + FC storage (128 GB RAM, Xeon 32 cores, SAS disks)

That's only part of the information we would need to be able to
give specific advice.  Please read this page:

https://wiki.postgresql.org/wiki/SlowQueryQuestions

One possibility is that you are running with the default
configuration, rather than having tuned for the hardware.  You are
very likely to need to adjust shared_buffers, effective_cache_size,
work_mem, maintenance_work_mem, random_page_cost, cpu_tuple_cost,
and (at least for the second machine) effective_io_concurrency.  If
the queries have a lot of joins you may need to increase
from_collapse_limit and/or join_collapse_limit.  You also may need
to adjust [auto]vacuum and/or background writer settings.  Various
OS settings may matter, too.

To get a handle on all this, it might be worth looking for Greg
Smith's book on PostgreSQL high performance.


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


-- 
Sent via pgsql-performance mailing list (pgsql-performance@postgresql.org)
To make changes to your subscription:
http://www.postgresql.org/mailpref/pgsql-performance