Message-ID: <4CF809DC.6040007@techbaza.pl>
Date: Thu, 02 Dec 2010 22:04:28 +0100
From: Piotr Czekalski <pczekalski@techbaza.pl>
Organization: TECHBAZA.PL
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To: pgsql-performance@postgresql.org
Subject: Multicore Postgres 9.0.1 issue - single transaction problem.
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Hello Postgres Users.

Last days I've installed and configured new x64 release of PostgreSQL 
running Windows 2008 R2 with dual XEON 5530 processors (2x4xHT = 16 
working units). Previously the database was running on Fedora 12 x86_64 
under Microsoft hypervisor (HyperV) thus because of the network card 
driver limitation there was only one core available.

The problem I'm facing is a very long, single transaction lasting about 
12hours or even more (as it doesn't exist Pragma Autonomous Transaction 
like Oracle has) that consist of tones of PLPGSQL code, processing a lot 
of data, causing huge CPU load and disk drive transfers.
When moved to the x64 system as described above, the shared memory size 
is not a problem anymore, the disk channel is running very smoothly, the 
only suprising think is that the transaction above utilizes only one 
core of the machine - is it possible to parallelize it without rewriting 
all the code from scratch?

Is there any configuration parameter limiting number of CPUs? The 
release is a standard/public x64 binary of PostgreSQL 9.0.1, taken 
following official site.

Thanks in advance for any help.

Piotr Czekalski

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