From: Tom Lane <tgl@sss.pgh.pa.us>
To: Robins Tharakan <tharakan@gmail.com>
Cc: pgsql-performance@postgresql.org
Subject: Re: Bypassing useless ORDER BY in a VIEW
Date: Thu, 28 Feb 2008 12:13:40 -0500
Message-ID: <8366.1204218820@sss.pgh.pa.us> (raw)
In-Reply-To: <36af4bed0802280631ja29c636w2256fb329e14b95e@mail.gmail.com>
References: <36af4bed0802280631ja29c636w2256fb329e14b95e@mail.gmail.com>
"Robins Tharakan" <tharakan@gmail.com> writes:
> If I give an ORDER BY clause in a VIEW and then use it in another query
> where the VIEW's ORDER BY is immaterial, would the planner be able to
> discard this ORDER BY clause ?
No. That's a feature not a bug; the sorts of cases where you want an
ORDER BY in a subquery, it's because you really want those rows computed
in that order (eg you've got side-effect-causing functions reading the
results). Postgres will never discard an ORDER BY as "immaterial".
A rule of thumb is that ORDER BY in a view is bad design, IMHO.
regards, tom lane
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To: pgsql-performance@postgresql.org
Cc: tgl@sss.pgh.pa.us, tharakan@gmail.com
Subject: Re: Bypassing useless ORDER BY in a VIEW
In-Reply-To: <8366.1204218820@sss.pgh.pa.us>
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