Re: [PERFORM] A Better External Sort? - Mailing list pgsql-hackers

From Hannu Krosing
Subject Re: [PERFORM] A Better External Sort?
Date
Msg-id 1128375790.5882.18.camel@fuji.krosing.net
Whole thread Raw
In response to Re: [PERFORM] A Better External Sort?  (Josh Berkus <josh@agliodbs.com>)
Responses Re: [PERFORM] A Better External Sort?  ("Luke Lonergan" <llonergan@greenplum.com>)
Re: [PERFORM] A Better External Sort?  (Michael Stone <mstone+postgres@mathom.us>)
List pgsql-hackers
On E, 2005-10-03 at 14:16 -0700, Josh Berkus wrote:
> Jeff,
>
> > > Nope, LOTS of testing, at OSDL, GreenPlum and Sun.   For comparison, A
> > > Big-Name Proprietary Database doesn't get much more than that either.
> >
> > I find this claim very suspicious.  I get single-threaded reads in
> > excess of 1GB/sec with XFS and > 250MB/sec with ext3.
>
> Database reads?  Or raw FS reads?  It's not the same thing.

Just FYI, I run a count(*) on a 15.6GB table on a lightly loaded db and
it run in 163 sec. (Dual opteron 2.6GHz, 6GB RAM, 6 x 74GB 15k  disks in
RAID10, reiserfs). A little less than 100MB sec.

After this I ran count(*) over a 2.4GB file from another tablespace on
another device (4x142GB 10k disks in RAID10) and it run 22.5 sec on
first run and 12.5 on second.

db=# show shared_buffers ;
 shared_buffers
----------------
 196608
(1 row)

db=# select version();
                                          version
--------------------------------------------------------------------------------------------
 PostgreSQL 8.0.3 on x86_64-pc-linux-gnu, compiled by GCC cc (GCC) 3.3.6
(Debian 1:3.3.6-7)
(1 row)


--
Hannu Krosing <hannu@skype.net>


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