Database Reference
In-Depth Information
3.
When the test is successful, the query optimizer verifies whether the SQL plan baseline
contains the execution plan generated without the SQL plan baseline. If it's contained
within it and accepted (trusted), it's executed.
4.
If another accepted execution plan is stored in the SQL plan baseline, the hints associated
to it are used for the generation of another execution plan. Note that if the SQL plan
baseline contains several accepted execution plans, the query optimizer selects the one
with the lowest cost.
5.
Lastly, the query optimizer checks whether the execution plan generated with the
information provided by the SQL plan baseline reproduced the expected execution
plan. Only if this last check is fulfilled, the execution plan can be used. If it's not satisfied,
the query optimizer tries the other accepted execution plans or, if all of them are
unreproducible, it falls back to the execution plan generated without the SQL plan baseline.
