Date: Thu, 18 Sep 2014 17:09:20 +0200 (CEST)
From: "Mkrtchyan, Tigran" <tigran.mkrtchyan@desy.de>
To: Jeff Janes <jeff.janes@gmail.com>
Cc: pgsql-performance@postgresql.org
Message-ID: <747323809.44735.1411052960344.JavaMail.zimbra@desy.de>
In-Reply-To: 
 <CAMkU=1zhg1pQrh7BfafTQUezbNkgy=s778UyssmNKX6xKDJ3sA@mail.gmail.com>
References: <45142416.42827.1411033201079.JavaMail.zimbra@desy.de>
 <88549888.42916.1411034301200.JavaMail.zimbra@desy.de>
 <CAMkU=1zhg1pQrh7BfafTQUezbNkgy=s778UyssmNKX6xKDJ3sA@mail.gmail.com>
Subject: Re: postgres 9.3 vs. 9.4
MIME-Version: 1.0
Content-Type: text/plain; charset=utf-8
Content-Transfer-Encoding: 7bit
Thread-Topic: postgres 9.3 vs. 9.4
Thread-Index: lW0qAtsPwJXEHvjzSG3qkQamGbYrhg==
Precedence: bulk
Sender: pgsql-performance-owner@postgresql.org


----- Original Message -----
> From: "Jeff Janes" <jeff.janes@gmail.com>
> To: "Tigran Mkrtchyan" <tigran.mkrtchyan@desy.de>
> Cc: pgsql-performance@postgresql.org
> Sent: Thursday, September 18, 2014 4:56:22 PM
> Subject: Re: [PERFORM] postgres 9.3 vs. 9.4
> 
> On Thu, Sep 18, 2014 at 2:58 AM, Mkrtchyan, Tigran <tigran.mkrtchyan@desy.de
> > wrote:
> 
> >
> >
> > Hi Folk,
> >
> > I am trying to investigate some performance issues which we have with
> > postgres
> > (a different topic by itself) and tried postgres.9.4beta2, with a hope
> > that it
> > perform better.
> >
> > Turned out that 9.4 is 2x slower than 9.3.5 on the same hardware.
> >
> > Some technical details:
> >
> >   Host: rhel 6.5 2.6.32-431.23.3.el6.x86_64
> >   256 GB RAM, 40 cores, Intel(R) Xeon(R) CPU E5-2660 v2 @ 2.20GHz
> >   2x160GB  PCIe SSD DELL_P320h-MTFDGAL175SAH ( on one 9.3, on an other one
> > 9.4 )
> >
> 
> Why are the versions segregated that way?  Are you sure they are configured
> identically?


es, they are configured identically
> 
> 
> >
> > postgres tweaks:
> >
> >
> > default_statistics_target = 100
> > wal_writer_delay = 10s
> > vacuum_cost_delay = 50
> > synchronous_commit = off
> >
> 
> Are you sure that synchronous_commit is actually off on the 9.4 instance?


yes, synchronous_commit is off.

> 
> 9.3.5:
> >
> > # /usr/pgsql-9.3/bin/pgbench -r -j 1 -c 1 -T 60
> >
> 
> ...
> 
> 
> >        0.035940        END;
> >
> >
> > 9.4beta2:
> >
> ...
> 
> >         0.957854        END;
> >
> 
> Looks like IO.

Postgres internal IO? May be. We get 600MB/s on this SSDs.


Tigran.

> 
> Cheers,
> 
> Jeff
> 


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