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To: David Fetter <david@fetter.org>
cc: PostgreSQL Docs <pgsql-docs@postgresql.org>
Subject: Re: Missing information on Expressional Indexes 
In-reply-to: <20100317001401.GJ21279@fetter.org> 
References: <20100317001401.GJ21279@fetter.org>
Comments: In-reply-to David Fetter <david@fetter.org>
	message dated "Tue, 16 Mar 2010 17:14:01 -0700"
Date: Wed, 17 Mar 2010 00:47:51 -0400
Message-ID: <20306.1268801271@sss.pgh.pa.us>
From: Tom Lane <tgl@sss.pgh.pa.us>
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David Fetter <david@fetter.org> writes:
> I think this page should mention that the expressions used in an
> expressional index need to be equivalent to an IMMUTABLE function, and
> the docs don't say so.

Sure they do, see CREATE INDEX:

	All functions and operators used in an index definition must be
	"immutable" ...

			regards, tom lane