Questions on SQL Plan Management

Hello All,

I wonder how many people are using SQL Plan Management? Is it really valuable to use it, as I know it has some overhead?

I am testing this feature, but found EXECUTIONS, ELAPSED_TIME and CPU_TIME in DBA_SQL_PLAN_BASELINES are all zeros after running SPM for a few weeks, even if the plans are accepted and executed. Do I mis-setting something?

Thanks,

John