Re: EXPLAIN PLAN differences

I think plan stability is intended for once you've tuned some code and you want to cement the execution plan, such that changes to the database don't screw it up. This might be what you're looking for.

However, it might also be that you haven't yet isolated the optimum execution plan, and have a development environment that lacks all the data existing on the production environment. Using DBMS_STATS, you can export statistics (.EXPORT_SCHEMA_STATS), move to new environment (Exp/Imp), import statistics (.IMPORT_SCHEMA_STATS), and the CBO should respond as if all the data from the production system were present in the development environment. This would allow you to tune your code in development.

--BP

traceable1_at_hotmail.com (traceable1) wrote in message news:<8551d8c9.0206040837.364b51f7_at_posting.google.com>...
> Please Help!!
>
> If I do an execution plan on the same query on 2 different boxes, I
> get different results (Cost 26 vs 158). What does this mean? I'm
> trying to make the two databases behave the same, but they will not.
> One box has a lot more data than the other, but statistics have been
> run. I've checked the OPTIMIZER_MODE, what else could be causing the
> difference?
> They are both Oracle 8.1.7 on W2K.
>
> Any thoughts are very much appreciated!!
>
> Trace
Received on Wed Jun 05 2002 - 19:53:43 CDT