Kbase 15676: Oracle Rule-base vs cost-base optimization
| Autor |
Progress Software Corporation - Progress |
| Acesso |
Público |
| Publicação |
5/10/1998 |
|
Oracle Rule-base vs cost-base optimization
Progress have typically seen better (and more consistent) results
using rule based. The hints generated by the DataServer are rule
based. The DataServer was written before ORACLE offered cost based
optimization (which, they are still making refinements to).
From past experiences, we have seen ORACLE make poor cost based
choices when the statistics are not up to date on ALL the tables
in a join. Also, if cost based choices depend upon data values
in the query, it should be known that the DataServer typically uses
bind variables (to make the sql more reusable) and ORALCE therefore
does not know the values until execute time. With defered execution
(on ORACLE's part) this may not make a difference.
04-26-96 ik
Progress Software Technical Support Note # 15676