Creating a plan hint from an access plan comparison result
If a SQL statement has regressed, you can create a plan
hint for it. With a plan hint, you can set certain criteria to assist
the cost-based optimizer in selecting the optimal execution plan.
Restoring a previous access plan
If the access plan has regressed and you are using DB2 for z/OS Version
9 or higher, you can revert to a previously stored access plan.