

	I need to check the scalability of a machine with postgresql and Im doing it 
with pgbench but Im getting values with a variation of a 40% with the same 
pgbench call...

	Just the same variation if I restart posgresql or overwrite the db...

	So just wondering if theres another benchmarking tool for postgres...

	Perhaps should I write my own one?

Tue, 26 Jun 2001 19:41:28 +0200
=?iso-8859-1?q?V=EDctor=20Romero?= <romero@kde.org>
Benchmarking
> 	I need to check the scalability of a machine with postgresql and Im doing it 
> with pgbench but Im getting values with a variation of a 40% with the same 
> pgbench call...

You might be looking at the effect of the kernel buffer cache. Try run
pgbench several times with same settings. Another point is how many
transactions pgbench runs (-t option). More transactions would give
more statble results. Here is my small script to run pgbench.  I
usually run it 2 or 3 times and take only the last run result.

#! /bin/sh
pgbench -i -s 2 test
for i in 1 2 4 8 16 32 64 128
do
	t=`expr 640 / $i`
	pgbench -t $t -c $i test
	echo "===== sync ======"
	sync;sync;sync;sleep 10
	echo "===== sync done ======"
done

Wed, 27 Jun 2001 10:11:23 +0900
Tatsuo Ishii <t-ishii@sra.co.jp>
Re: Benchmarking