From: Tom Lane <tgl@sss.pgh.pa.us>
To: Henrique Engelmann <henriqueengelmann@yahoo.com.br>
Cc: pgsql-performance@postgresql.org
Subject: Re: Clustered tables and seqscan disabled
Date: Sat, 10 Dec 2005 11:53:50 -0500
Message-ID: <21005.1134233630@sss.pgh.pa.us> (raw)
In-Reply-To: <20051210152937.71243.qmail@web36410.mail.mud.yahoo.com>
References: <20051210152937.71243.qmail@web36410.mail.mud.yahoo.com>
Henrique Engelmann <henriqueengelmann@yahoo.com.br> writes:
> I suggested changing the application and including a order by clause... but
> the software house didn´t make it because they said the system was originally designed for oracle and they did not need to use the ORDER BY clause with Oracle and even so the data were always retrieved in primary index order.
> I´m thinking with myself ... what kind of problems will they have in the future?
If you aren't working with these people any more, be glad. They are
obviously utterly incompetent. The SQL standard is perfectly clear
about the matter: without ORDER BY, there is no guarantee about the
order in which rows are retrieved. The fact that one specific
implementation might have chanced to produce the rows in desired order
(under all the conditions they had bothered to test, which I bet wasn't
a lot) does not make their code correct.
regards, tom lane
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To: pgsql-performance@postgresql.org
Cc: tgl@sss.pgh.pa.us, henriqueengelmann@yahoo.com.br
Subject: Re: Clustered tables and seqscan disabled
In-Reply-To: <21005.1134233630@sss.pgh.pa.us>
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