Re: Indices for both where and order by.

From: Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us>
To: Niclas Gustafsson <Niclas(dot)Gustafsson(at)codesense(dot)com>
Cc: pgsql-general(at)postgresql(dot)org
Subject: Re: Indices for both where and order by.
Date: 2002-05-23 20:21:56
Message-ID: 23445.1022185316@sss.pgh.pa.us
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Niclas Gustafsson <Niclas(dot)Gustafsson(at)codesense(dot)com> writes:
> Select * from hs where tcode = 'XXZZ' order by timestamp

> An idea was to create an Index on both tcode and timestamp, like this
> Create index hs_tcode_timestamp_idx on hs (tcode, timestamp)

> Am I completely wrong here, or could the planner not use it for both the
> where and the sorting?

You'd have to write
Select * from hs where tcode = 'XXZZ' order by tcode, timestamp
to get the planner to realize that the index ordering is what's wanted.

regards, tom lane

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