Re: 7.2 is slow? - Mailing list pgsql-hackers

From Jussi Mikkola
Subject Re: 7.2 is slow?
Date
Msg-id 3C1F2055.6565CB9@bonware.com
Whole thread Raw
In response to 7.2 is slow?  (Tatsuo Ishii <t-ishii@sra.co.jp>)
List pgsql-hackers
I haven't tested with the new 7.2 betas, but here are some results from
7.1.

We have a developement computer, IBM x series 250, with 4 processors
(PIII Xeon 750Mhz), 1 Gb memory and  2SCSI disks (u160).

The software is writing new rows to a table, and after this it reads the
id from that row. There are currently about 50 connections doing the
same thing.

When I run this test with the Redhat 7.1 SMP kernel, I noticed, that the
processors are more than 90% idle. Disks utilisation is not the
bottleneck either, since there is very low disk usage. Some data is
written to disks every 4-5 seconds. Fsync is turned of. In transactions,
this means about 200 inserted rows per second. The software that is used
to give the feed, is capable of several thousand rows per second.

Okey, so I tried this also with the same computer, but using the not SMP
supported kernel. So only with one processor. The result was about 600
rows per second. The configuration file was unchanged. Now, the
processor is about 100% utilized.

I didn't find any parameters that should help in this, but if you have a
version of 7.2 that you would like to get information about, let me
know, so I'll test.

Jussi





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