Message-ID: 
 <39160.131.107.65.118.1184775275.squirrel@webmail.benjaminarai.com>
Date: Wed, 18 Jul 2007 09:14:35 -0700 (PDT)
Subject: Parrallel query execution for UNION ALL Queries
From: "Benjamin Arai" <me@benjaminarai.com>
To: pgsql-performance@postgresql.org, pgsql-general@postgresql.org
Reply-To: me@benjaminarai.com
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Hi,

If I have a query such as:

SELECT * FROM (SELECT * FROM A) UNION ALL (SELECT * FROM B) WHERE
blah='food';

Assuming the table A and B both have the same attributes and the data
between the table is not partitioned in any special way, does Postgresql
execute WHERE blah="food" on both table simultaiously or what?  If not, is
there a way to execute the query on both in parrallel then aggregate the
results?

To give some context, I have a very large amount of new data being loaded
each week.  Currently I am partitioning the data into a new table every
month which is working great from a indexing standpoint.  But I want to
parrallelize searches if possible to reduce the perofrmance loss of having
multiple tables.

Benjamin