From: | Jim Nasby <Jim(dot)Nasby(at)BlueTreble(dot)com> |
---|---|
To: | Anton <djeday84(at)gmail(dot)com>, pgsql-general <pgsql-general(at)postgresql(dot)org> |
Subject: | Re: [HACKERS] optimization join on random value |
Date: | 2015-05-04 02:10:02 |
Message-ID: | 5546D4FA.6080904@BlueTreble.com |
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Lists: | pgsql-general pgsql-hackers |
On 5/3/15 4:15 PM, Anton wrote:
> Hello guru of postgres, it's possoble to tune query with join on random
> string ?
> i know that it is not real life example, but i need it for tests.
Moving to -general, which is the proper list for this. (BCC -hackers)
> soe-# WHERE customer_id = trunc( random()*45000) ;
You could create a temp table with the random value and JOIN to it:
CREATE TEMP TABLE rnd AS SELECT random()*45000;
Another option might be to use a prepared statement:
PREPARE test AS SELECT ... WHERE customer_id = $1;
EXECUTE test( random()*45000 );
--
Jim Nasby, Data Architect, Blue Treble Consulting
Data in Trouble? Get it in Treble! http://BlueTreble.com
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