On Fri, 8 Sep 2006, Heikki Linnakangas wrote:

Date: Fri, 08 Sep 2006 15:22:19 +0100
From: Heikki Linnakangas <[EMAIL PROTECTED]>
To: Praveen Kumar N <[EMAIL PROTECTED]>
Cc: pgsql-hackers@postgresql.org
Subject: Re: [HACKERS] postgresql shared buffers

Praveen Kumar N wrote:

Following is the output of query i have executed.

Looks like Alvaro guessed right. It reads both relations in sequence, sorts them in temporary storage, outside bufmgr, and then does a merge join on the sorted inputs.

could you tell me how can we trace that? I mean which functions shall I checkout for that.

If you want to see the behavior you expected, I think you need to define indexes on a2 and b2, if you don't have them already, and coerce the planner to choose a nested loop join. I'd suggest using "SET enable_seqscan=false; SET enable_bitmapscan=false;" and see if that gets you a nested loop join.

 N Praveen Kumar
 Btech-IV CSE

        Imagination is more important than knowledge...
                                --Albert Einstein

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