Message-ID: <460E8427.5090502@cse.ohio-state.edu>
Date: Sat, 31 Mar 2007 11:54:15 -0400
From: Xiaoning Ding <dingxn@cse.ohio-state.edu>
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To: Christopher Browne <cbbrowne@acm.org>
CC: pgsql-performance@postgresql.org
Subject: Re: scalablility problem
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Christopher Browne wrote:
> Quoth dingxn@cse.ohio-state.edu (Xiaoning Ding):
>> When I run multiple TPC-H queries (DBT3) on  postgresql, I found the system
>> is not scalable.  My machine has 8GB memory, and 4 Xeon Dual Core processor
>> ( 8 cores in total). OS kernel is linux 2.6.9. Postgresql is 7.3.18. I
> 
>> I think it might be caused by some contentions. But I do not know postgresql
>> much. May anybody give me some clue to find the reasons?
> 
> Two primary issues:
> 
> 1.  You're running a horrendously ancient version of PostgreSQL.  The
> 7.3 series is Really Old.  Newer versions have *enormous*
> improvements that are likely to be *enormously* relevant.
>
> Upgrade to 8.2.
8.2 is really much better.
> 
> 2.  There are known issues with the combination of Xeon processors and
> PAE memory addressing; that sort of hardware tends to be *way* less
> speedy than the specs would suggest.
I think PAE slows each query process. It would not affect scalability.

> There have been "context switching" issues on this sort of hardware
> that are enormously worsened if you're running on a version of
> PostgreSQL that is 4 major releases out of date.
How does PG 8.2 address this issue? by setting processor affinity?

Thanks!

Xiaoning