From: Andres Freund <andres@anarazel.de>
To: Jan Gunnar Dyrset <jan.g.dyrset@cybernetica.no>
Cc: pgsql-performance@postgresql.org <pgsql-performance@postgresql.org>
Subject: Re: PostgreSQL disk fragmentation causes performance problems on Windows
Date: Wed, 29 Apr 2015 10:08:54 +0200
Message-ID: <20150429080854.GD14535@awork2.anarazel.de> (raw)
In-Reply-To: <20150429080639.GC14535@awork2.anarazel.de>
References: <AMXPR05MB120CFF5F9A4825A531E2018A1ED0@AMXPR05MB120.eurprd05.prod.outlook.com>
<20150429080639.GC14535@awork2.anarazel.de>
List-Unsubscribe: <mailto:majordomo@postgresql.org?body=unsub%20pgsql-performance>
On 2015-04-29 10:06:39 +0200, Andres Freund wrote:
> Hi,
>
> On 2015-04-23 19:47:06 +0000, Jan Gunnar Dyrset wrote:
> > I am using PostgreSQL to log data in my application. A number of rows
> > are added periodically, but there are no updates or deletes. There are
> > several applications that log to different databases.
> >
> > This causes terrible disk fragmentation which again causes performance
> > degradation when retrieving data from the databases. The table files
> > are getting more than 50000 fragments over time (max table size about
> > 1 GB).
> >
> > The problem seems to be that PostgreSQL grows the database with only
> > the room it need for the new data each time it is added. Because
> > several applications are adding data to different databases, the
> > additions are never contiguous.
>
> Which OS and filesystem is this done on? Because many halfway modern
> systems, like e.g ext4 and xfs, implement this in the background as
> 'delayed allocation'.
Oh, it's in the subject. Stupid me, sorry for that. I'd consider testing
how much better this behaves under a different operating system, as a
shorter term relief.
Greetings,
Andres Freund
--
Sent via pgsql-performance mailing list (pgsql-performance@postgresql.org)
To make changes to your subscription:
http://www.postgresql.org/mailpref/pgsql-performance
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: andres@anarazel.de, jan.g.dyrset@cybernetica.no
Subject: Re: PostgreSQL disk fragmentation causes performance problems on Windows
In-Reply-To: <20150429080854.GD14535@awork2.anarazel.de>
* 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