From: Bruce Momjian <bruce@momjian.us>
To: anarazel@anarazel.de <andres@anarazel.de>
Cc: Ondrej Ivanič <ondrej.ivanic@gmail.com>
Cc: J Ramesh Kumar <rameshj1977@gmail.com>
Cc: pgsql-performance@postgresql.org
Subject: Re: High Disk write and space taken by PostgreSQL
Date: Thu, 16 Aug 2012 12:23:03 -0400
Message-ID: <20120816162303.GC8359@momjian.us> (raw)
In-Reply-To: <d541296c-ddb4-44d6-b546-8dec81ae1fb8@email.android.com>
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<CA+-36iGrckXc3bvpJJ0AECjFeaoDpX892jyyJ2Hk-K=bHwDSvA@mail.gmail.com>
<CAOR=d=1H1-p7SovzTh0y0NWvo9a9Xf7uvH8iGPJA6NZy2oJv8g@mail.gmail.com>
<CA+-36iFvm6fYrBYOxjPAhGkxN34P01vy7MqiCz0inZ1dcnUpEA@mail.gmail.com>
<CAM6mieJqV0=KX2MuTXz+jr8_RCpzmNn0w6A9E5XsAcxKsSP5SQ@mail.gmail.com>
<20120816145321.GA8359@momjian.us>
<d541296c-ddb4-44d6-b546-8dec81ae1fb8@email.android.com>
On Thu, Aug 16, 2012 at 06:07:26PM +0200, anarazel@anarazel.de wrote:
>
>
> Bruce Momjian <bruce@momjian.us> schrieb:
>
> >On Thu, Aug 16, 2012 at 03:48:57PM +1000, Ondrej Ivanič wrote:
> >> Hi,
> >>
> >> On 16 August 2012 15:40, J Ramesh Kumar <rameshj1977@gmail.com>
> >wrote:
> >> > As you said, MySQL with MyISAM is better choice for my app. Because
> >I don't
> >> > need transaction/backup. May be I'll try with InnoDB and find the
> >disk
> >> > write/space difference. Is there any similar methods available in
> >postgresql
> >> > like MyISAM engine ?
> >>
> >> You can try unlogged tables:
> >> http://www.postgresql.org/docs/9.1/static/sql-createtable.html
> >>
> >> If specified, the table is created as an unlogged table. Data written
> >> to unlogged tables is not written to the write-ahead log (see Chapter
> >> 29), which makes them considerably faster than ordinary tables.
> >> However, they are not crash-safe: an unlogged table is automatically
> >> truncated after a crash or unclean shutdown. The contents of an
> >> unlogged table are also not replicated to standby servers. Any
> >indexes
> >> created on an unlogged table are automatically unlogged as well;
> >> however, unlogged GiST indexes are currently not supported and cannot
> >> be created on an unlogged table.
> >
> >I would set full_page_writes = off too.
> Why? There shouldn't be any such writes on unlogged tables.
True. I was thinking more of the logged tables, and the system tables.
--
Bruce Momjian <bruce@momjian.us> http://momjian.us
EnterpriseDB http://enterprisedb.com
+ It's impossible for everything to be true. +
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To: pgsql-performance@postgresql.org
Cc: bruce@momjian.us, andres@anarazel.de, ondrej.ivanic@gmail.com, rameshj1977@gmail.com
Subject: Re: High Disk write and space taken by PostgreSQL
In-Reply-To: <20120816162303.GC8359@momjian.us>
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