Re: Optimization Analysis question

From: Sybrand Bakker <postbus_at_sybrandb.demon.nl>
Date: Fri, 30 Mar 2001 21:05:07 +0200
Message-ID: <tc9ma67mljq5aa@beta-news.demon.nl>

"Robert Chung" <robertch_at_mindspring.com> wrote in message news:3ac5d070.13145952_at_198.99.146.10...
>
> The DBA_TABLES view in up-to-date version of Oracle databases show the
> date tables were analyzed in "LAST_ANALYZED" column, but Oracle
> database 7.3.4 does not. Does anyone know how to find out
> when/whether tables were analyzed in 7.3.4 version of database?
>
> Also, does RULE based optimization change path when table size
> changes? I know COST based optimization does that for sure. Thank
> you in advance.
>
>

7.3.4 doesn't keep track of that.
Rule based optimization paths are independent of the table size, which can be a problem when all involved tables are small. However, I have seen many developers using CBO and the performance collapse when it came to the production, so be forwarned. Yet you should use CBO as it has so much more functionality and RBO will sooner or later be deleted.

Hth,

Sybrand Bakker, Oracle DBA Received on Fri Mar 30 2001 - 13:05:07 CST