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Message-ID: <46657180.7010604@enterprisedb.com>
Date: Tue, 05 Jun 2007 15:21:52 +0100
From: Heikki Linnakangas <heikki@enterprisedb.com>
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To: Markus Schiltknecht <markus@bluegap.ch>
CC: pgsql-performance@postgresql.org
Subject: Re: dbt2 NOTPM numbers
References: <466428F7.5010808@bluegap.ch> <46642B33.6030101@enterprisedb.com>
	<46642F2E.3080509@bluegap.ch> <4664748B.2060304@enterprisedb.com>
	<4665703E.3040905@bluegap.ch>
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Markus Schiltknecht wrote:
> Hi,
> 
> Heikki Linnakangas wrote:
>> I still suspect there's something wrong with plans, I doubt you can 
>> get that bad performance unless it's doing something really stupid.
> 
> Agreed, but I'm still looking for that really stupid thing...  AFAICT, 
> there are really no seqscans..., see the pg_stat_user_tables below.
> 
>> I'd suggest setting log_min_duration_statement = 5000, and seeing what 
>> you get. Also check pg_stat_user_table.seq_scan just to be extra sure 
>> there's no seq scans.
> 
> I've also added some of the log messages for min_duration_statement 
> below. Both were taken after two or three test runs.
> 
> I'm really wondering, if the RAID 6 of the ARECA 1260 hurts so badly. 
> That would be disappointing, IMO. I'll try if I can reconfigure it to do 
> RAID 1+0, and then test again. (Unfortunately the box has already been 
> shipped to the customer, so that's getting tricky to do via ssh..:-( ).

Maybe, TPC-C is very write-intensive. I don't know much about RAID 
stuff, but I think you'd really benefit from a separate WAL drive. You 
could try turning fsync=off to see if that makes a difference.

Oh, and how many connections are you using? DBT-2 can be quite sensitive 
to that. 30 seems to work pretty well for me.

-- 
   Heikki Linnakangas
   EnterpriseDB   http://www.enterprisedb.com