RE: histograms, buckets, and bind variables

  • From: "Stephens, Chris" <ChrisStephens@xxxxxxx>
  • To: <oracle-l@xxxxxxxxxxxxx>
  • Date: Wed, 17 Nov 2004 12:05:10 -0500

This is actually something I've never quite understood.


...so with 9i bind variables don't completely prevent parsing correct?
...they just make a softer hard/soft parse?=20

-----Original Message-----
From: oracle-l-bounce@xxxxxxxxxxxxx
[mailto:oracle-l-bounce@xxxxxxxxxxxxx] On Behalf Of Gogala, Mladen
Sent: Wednesday, November 17, 2004 11:31 AM
To: 'ryan_gaffuri@xxxxxxxxxxx'; oracle-l@xxxxxxxxxxxxx
Subject: RE: histograms, buckets, and bind variables

Ryan, the problem you are talking about is an 8i problem. Version 9,
especially 9.2 developed so called peeping Tom feature which makes
optimizer peek into the bind variables for the SQL the first time SQL is
executed. Values of those bind variables are then used to compute a
plan.

--
Mladen Gogala
A & E TV Network
Ext. 1216


> -----Original Message-----
> From: ryan_gaffuri@xxxxxxxxxxx [mailto:ryan_gaffuri@xxxxxxxxxxx]
> Sent: Wednesday, November 17, 2004 11:07 AM
> To: oracle-l@xxxxxxxxxxxxx
> Subject: histograms, buckets, and bind variables
>=20
>=20
> I could have swarn I read that if you use bind variables oracle=20
> ignores histograms. We are noticing different query plans based on the

> number of buckets our histograms have while our queries are using bind

> variables.
> One of the guys did a 10053 trace and added up the cost oracle is=20
> calculating and it is changing based on number of buckets even when=20
> bind variables are used.
>=20
> anyone else notice this?=20
>=20
> --
> //www.freelists.org/webpage/oracle-l
>=20
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