From: "Carlo Stonebanks" <stonec.register@sympatico.ca>
Subject: Does FILTER in SEQSCAN short-circuit AND?
Date: Tue, 18 May 2010 18:28:25 -0400
Organization: Hub.Org Networking Services
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To: pgsql-performance@postgresql.org

Sample code:

SELECT *
FROM MyTable
WHERE foo = 'bar' AND MySlowFunc('foo') = 'bar'

Let's say this required a SEQSCAN because there were no indexes to support 
column foo. For every row where foo <> 'bar' would the filter on the SEQSCAN 
short-circuit the AND return false right away, or would it still execute 
MySlowFunc('foo') ?

Thanks!

Carlo