Re: 10053 curiosity (changes with and without bind)

From: Wolfgang Breitling <breitliw_at_centrexcc.com>
Date: Mon, 24 May 2004 21:38:49 -0600
Message-Id: <6.1.0.6.2.20040524213617.02b12250@pop.centrexcc.com>

Your columns have histograms on them. The query with the literal values uses the information in the histogram, the one with bind variables does not ( in 8i, in 9 the optimizer will use the bind value during the first parse of the sql).

At 09:16 PM 5/24/2004, Henry Poras wrote:
>I'm going slightly batty(er) trying to understand why Oracle (8.1.7.4) is
>using two different execution plans for two nearly identical queries. The
>only difference between the two is that one uses a bind variable where the
>other uses a hard coded value. The field in question, however, is NOT
>NULL, with only one distinct value (# of distinct values in dba_tab_column
>shows 1). Trying to find the source of this difference, I looked at a
>10053 trace and found the following:
>WITH BIND
>SINGLE TABLE ACCESS PATH
>Column: SETID Col#: 1
> NDV: 1 NULLS: 0 DENS:
> 6.6667e-03
>Column: EFFDT Col#: 5
> NDV: 22 NULLS: 0 DENS: 2.4626e-05

regards

Wolfgang Breitling
Centrex Consulting Corporation
www.centrexcc.com

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Received on Mon May 24 2004 - 22:35:59 CDT