From: Karsten Hilbert <Karsten.Hilbert@gmx.net>
To: pgsql-sql@postgresql.org
Subject: Re: Find out whether a view's column is indexed?
Date: Thu, 10 Jun 2004 16:06:27 +0200
Message-ID: <20040610160627.B1308@hermes.hilbert.loc> (raw)
In-Reply-To: <37936EEC582B394A9E1AA951991A551604C3C0@dev001_pdc.Dev.cadcorp.net>
References: <37936EEC582B394A9E1AA951991A551604C3C0@dev001_pdc.Dev.cadcorp.net>
> and I can see whether a sequential scan or an index scan is
> performed, but parsing the output of EXPLAIN programmatically
> is nearly impossible. Anyway the words 'Index Scan' and 'Seq
> Scan' can change without notice, maybe even from one locale to
> another.
I think you are operating under the faulty assumption that
'Index Scan' in EXPLAIN output signifies that a column is
*indexed*. What it really tells you is whether an index is
actually *used* when getting data from a column. That of
course requires an index to be there. However, an index being
there doesn't guarantee it being used.
Karsten
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To: pgsql-sql@postgresql.org
Cc: Karsten.Hilbert@gmx.net
Subject: Re: Find out whether a view's column is indexed?
In-Reply-To: <20040610160627.B1308@hermes.hilbert.loc>
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