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From: Richard Huxton <dev@archonet.com>
To: kevin kempter <kevin@kevinkempterllc.com>
Cc: pgsql-performance@postgresql.org
Subject: Re: Join runs for > 10 hours and then fills up >1.3TB of disk space
Date: Fri, 16 May 2008 09:16:19 +0100
Message-ID: <482D42D3.6000302@archonet.com> (raw)
In-Reply-To: <8B5A9097-109E-45F5-A658-7FC723EA75F3@kevinkempterllc.com>
References: <CEFBA6FF-0E0A-41A0-959E-7DBBDA296825@kevinkempterllc.com>
	<482D3A60.30006@archonet.com>
	<8B5A9097-109E-45F5-A658-7FC723EA75F3@kevinkempterllc.com>

kevin kempter wrote:
> I'm expecting 9,961,914 rows returned. Each row in the big table should 
> have a corresponding key in the smaller tale, I want to basically 
> "expand" the big table column list by one, via adding the appropriate 
> key from the smaller table for each row in the big table. It's not a 
> cartesion product join.

Didn't seem likely, to be honest.

What happens if you try the query as a cursor, perhaps with an order-by 
on customer_id or something to encourage index use? Do you ever get a 
first row back?

In fact, what happens if you slap an index over all your join columns on 
xsegment_dim? With 7,000 rows that should make it a cheap test.

-- 
   Richard Huxton
   Archonet Ltd



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