From: Heikki Linnakangas <heikki@enterprisedb.com>
To: Markus Schiltknecht <markus@bluegap.ch>
Cc: pgsql-performance@postgresql.org
Subject: Re: dbt2 NOTPM numbers
Date: Tue, 05 Jun 2007 15:21:52 +0100
Message-ID: <46657180.7010604@enterprisedb.com> (raw)
In-Reply-To: <4665703E.3040905@bluegap.ch>
References: <466428F7.5010808@bluegap.ch>
<46642B33.6030101@enterprisedb.com>
<46642F2E.3080509@bluegap.ch>
<4664748B.2060304@enterprisedb.com>
<4665703E.3040905@bluegap.ch>
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
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To: pgsql-performance@postgresql.org
Cc: heikki@enterprisedb.com, markus@bluegap.ch
Subject: Re: dbt2 NOTPM numbers
In-Reply-To: <46657180.7010604@enterprisedb.com>
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