A few questions and suggestions:
1) What version of Oracle are you running?
2) Identify the SQL that is run most frequently and compare the explain
plans under RULE and CHOOSE
3) Do the same with any reports. These are most likely to suddenly do
ridiculous sort/merge joins killing performance.
4
You should in test env before changing the optimizer
through intensive benchmarks. However, if you are
working with 8i, try with outlines. Consider changing
to first_rows and evaluate the set of
optimizer_index_caching, optimizer_index_cost_adj and
optimizer_max_permutations.
Regards.
--- Shaw
At least now you can go with CHOOSE instead of strictly cost based. Its
a much smaller plunge, you can pick and choose which objects to try
first.
-Original Message-
Sent: Tuesday, January 22, 2002 12:06 PM
To: Multiple recipients of list ORACLE-L
I have a large app that is still ru
I have a large app that is still running rule based, we are finally going to
take the plunge and try to start going cost based. The first time we tried
this the performance was terrible in a lot of places. Does anyone have any
good white papers or hints/tips on what to look for on areas that migh