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Home -> Community -> Mailing Lists -> Oracle-L -> RE: Re: how to get oracle to ignore an index
Are there rows for which the column(s) indexed by partmaster_partno are =
NULL? If so, that will prevent the index
access path being used.
-----Original Message-----
From: Jesse, Rich [mailto:Rich.Jesse_at_qtiworld.com]
Sent: Friday, February 06, 2004 3:14 PM
To: 'oracle-l_at_freelists.org'
Subject: RE: Re: how to get oracle to ignore an index
Perhaps that is one case, but I just tried this:
SELECT /*+ index(pm partmaster_partno) */ *=20 FROM partmaster pm;
...where "partmaster" is an 8400 block table, and "partmaster_partno" is =
a
2-segment unique index, and Oracle still correctly chooses the FTS, even
though I hinted to use an index.
Rich
Rich Jesse System/Database Administrator rich.jesse_at_qtiworld.com Quad/Tech International, Sussex, WI =USA
Ryan
Here is the way I look at the issue you raise. Hints are coded as
comments, not a part of the SQL statement. If a hint has bad syntax, =
Oracle
does not error out, but treats the mangled hint as a comment. If the =
hint
refers to an index that doesn't exist, Oracle does not error out. That =
is
what I think is meant by saying that Oracle can ignore a hint if it =
chooses
to.
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