Re: Is mysql a RDBMS ?
From: Pablo Sanchez <honeypot_at_blueoakdb.com>
Date: 25 Aug 2003 16:07:19 GMT
Message-ID: <Xns93E27B3C0A94Epingottpingottbah_at_192.168.1.1>
Date: 25 Aug 2003 16:07:19 GMT
Message-ID: <Xns93E27B3C0A94Epingottpingottbah_at_192.168.1.1>
"Heikki Tuuri" <Heikki.Tuuri_at_innodb.com> wrote in
news:52h2b.18$G37.11_at_read3.inet.fi:
>> DISTINCT often improves performance by allowing the dbms to
>> ignore
> potential
>> duplicates that very often cannot even exist.
>
> Can you show statistics about that?
DISTINCT's often require a sort area to squish out dup's, which means a performance degradation.
-- Pablo Sanchez, Blueoak Database Engineering http://www.blueoakdb.comReceived on Mon Aug 25 2003 - 18:07:19 CEST