-Original Message-
From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED] On
Behalf Of Mark Richard
Sent: 08 July 2003 06:09
To: Multiple recipients of list ORACLE-L
Subject: Re: concatenated index
I didn't mean that including RULE will prevent the index from
being used - I
Thanks Stephane. Is there some place (some article) other
than the Oracle
Manual which deals with this(latest) features on the composite index
Asktom has or had an article on this try (will likely wrap)
http://asktom.oracle.com/pls/ask/f?p=4950:8:409221425463834426::NO::F495
Title: RE: concatenated index
no_index is a valid hint ... it tells Oracle that exclude specified index from your consideration.
Raj
Rajendra dot Jamadagni at nospamespn dot com
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of list ORACLE-L [EMAIL PROTECTED]
Subject: Re: concatenated index
Date: Mon, 07 Jul 2003 21:39:25 -0800
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Interestingly, the 'Novice DBA' mistake seems to be derived from a more
grounded (because I _believe_ that at one point in the past it has been
correct) urban legend, which is that the order of columns in an index
matters a lot, the most significant columns having to come first.
This
The order of the where clause is not important. Including the leading
(first) columns in the index is. If you remove the a = ? element from
any of the queries then it may stop using the index. Oracle is smart
enough to look at the entire where clause and work out what it can do to
achieve the
No more Oracle certifiable DBA
From: Mark Richard [EMAIL PROTECTED]
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To: Multiple recipients of list ORACLE-L [EMAIL PROTECTED]
Subject: Re: concatenated index
Date: Mon, 07 Jul 2003 20:09:24 -0800
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Sent by: Subject: Re: concatenated index
Mark,
You are wrong about the RBO. It takes conditions in the order it
finds them in the WHERE clause, but it has always been more subtle than
that - there is some weighting of conditions (column = constant better
than column = other_column, unique_index_column = other_column better
than
