Re: slow query - index usage question

From: Howard J. Rogers <howardjr2000_at_yahoo.com.au>
Date: Thu, 20 Mar 2003 06:27:16 +1100
Message-ID: <3m3ea.3760$dE2.9223@newsfeeds.bigpond.com>

> >Furthermore: it has been said often (by such knowledgeable people as
> >T.Kyte) that a hint is a hint not an order. A hint adjusts factors
> >that are taken into the calculation of the costs. So depending on the
> >information the optimizer has, it still can (and will) decide that it's
> >more cheaper to use a full table scan compared to an index fast full
scan.

I haven't been following this thread, but this particular bit is simply wrong. "Knowledgeable people", including Jonathan Lewis in this very group not more than about 6 weeks ago, have quite clearly stated that a hint is indeed an order and will not be ignored by the Optimizer, unless it is flatly invalid (directing the use of an invalid index, for example).

They are directives, not suggestions.

Regards
HJR Received on Wed Mar 19 2003 - 13:27:16 CST