pg.ddx.io  pgsql-performance@postgresql.org mailing list archive  

help / color / mirror / Atom feed

From: Mark Mielke <mark@mark.mielke.cc>
To: André Volpato <andre.volpato@ecomtecnologia.com.br>
Cc: pgsql-performance@postgresql.org
Subject: Re: Postgres not using array
Date: Thu, 21 Aug 2008 10:16:40 -0400
Message-ID: <48AD78C8.80500@mark.mielke.cc> (raw)
In-Reply-To: <48AD735D.6040403@ecomtecnologia.com.br>
References: <48AC8292.5000708@ecomtecnologia.com.br>
	<48AD735D.6040403@ecomtecnologia.com.br>

André Volpato wrote:
> In practice, I have noticed that dual 1.8 is worse than single 3.0. We 
> have another server wich
> is a Pentium D 3.0 GHz, that runs faster.
> ...
> Postgres read the array in less than 1 sec, and the other 10s he takes 
> 100% of CPU usage,
> wich is, in this case, one of the two cores at 1.8GHz.
>
> I am a bit confused about what CPU is best for Postgres. Our apps is 
> mostly read, with
> a few connections and heavy queryes.
> Does it worth a multi-core ?

How are you doing your benchmarking? If you have two or more queries 
running at the same time, I would expect the 1.8 Ghz x 2 to be 
significant and possibly out-perform the 3.0 Ghz x 1. If you usually 
only have one query running at the same time, I expect the 3.0 Ghz x 1 
to always win. PostgreSQL isn't good at splitting the load from a single 
client across multiple CPU cores.

Cheers,
mark

-- 
Mark Mielke <mark@mielke.cc>

view thread (12+ messages)  latest in thread

Message-ID: <48AD78C8.80500@mark.mielke.cc>
Permalink:  ../48AD78C8.80500@mark.mielke.cc/
Also on:    postgresql.org/message-id/48AD78C8.80500@mark.mielke.cc

copy link · copy postgr.es

reply

Reply instructions:

You may reply publicly to this message via plain-text email
using any one of the following methods:

* Reply to all the recipients using the --to and --cc options:
  reply via email

  To: pgsql-performance@postgresql.org
  Cc: mark@mark.mielke.cc, andre.volpato@ecomtecnologia.com.br
  Subject: Re: Postgres not using array
  In-Reply-To: <48AD78C8.80500@mark.mielke.cc>

* Save the following mbox file, import it into your mail client,
  and reply-to-all from there: mbox

This inbox is served by DDX for PostgreSQL; see mirroring instructions
for how to clone and mirror all data and code used for this inbox