SQL-Tuning with ADDM (Implement Execution Plan)

[Erich_1]

Hi all,
i have updated Oracel from 8.1.7 to 10G-R2, and now their are any recommandations (in the ADDM) to do:

- SQL statements consuming significant database time where found
- time spent on the CPU by the instance was responsible for a substantial part of database time
- individual SQL statments responsible for significant user I/O wait where found
....

My Question:
Can i implement the suggestions for the "Exectuion Plan modify" blindly, or is their any to attend?
Could the "new" Execution Plan gives an different output to the "old"?
Can i go back to the "old" execution plan ?

[Yogeeraj_1]

hi,

it is advisable not to blindly implement the solution provided.

I would suggest that you sit with the developers and try to take appropriate measures and implement solution (e.g. create new indexes) manually.


kind regards
yogeeraj

[mghosalk]

tuning one particular sql is like a double edge sword. for eg. if addm suggests creating index to help that query, but the same index could make other query slow if the cbo is not give right statistics.

u could go back to the old plan if you remove the implementations.

[Erich_1]

Thanks for your apply,

i think i will test step by step all advisoris and check in this way the performance. If the performance will be worse, than i could back to the old execution plan - Can i do this with the EM (Grid Control) ?

[mghosalk]

Erich,

u can go back to ADDM and select specific recommendations.
but then if permissible, you could run another addm to see how the changes affect.

-Mandar