Re: LBO/CBO

From: Peter van Rijn <p.vanrijnREMOVE_at_THISzhew.nl>
Date: Fri, 27 Sep 2002 13:12:10 +0200
Message-ID: <up8f9mai9f5h8a@corp.supernews.com>

Marc,

Using CHOOSE means, simply put, that Oracle will use CBO if statistics are available, else it will use RBO.
Either generate statistics (preferred) or use other optimizer mode (e.g. first_rows, all_rows etc.)

Peter

"Marc Zinzen" <mzinzen_at_genese.de> schreef in bericht news:3D9437D3.ACE15686_at_genese.de...
> Hi.
>
> PLAN_TABLE_OUTPUT
> --------------------------------------------------------------------------

--


>

> --------------------------------------------------------------------

> | Id  | Operation            |  Name       | Rows  | Bytes | Cost  |

> --------------------------------------------------------------------

> |   0 | SELECT STATEMENT

> |   1 |  TABLE ACCESS FULL   | T_IND_UNT   |       |       |       |

> --------------------------------------------------------------------

>

> Note: rule based optimization

> The Problem is the Note at the Bottem. Rule bases optimization.

> I did an alter session set optimizer_mode = choose;

> Still it says rule based. But i want to do this query Cost based.

> Where is the switch????? Does anybody know.

> Marc

>

Received on Fri Sep 27 2002 - 06:12:10 CDT