After optimizing information has been saved, if an operation is performed that increases the quantity of optimizing information, it might not be possible to completely restore this information even if the saved information is used.

The following operations increase the quantity of optimizing information:

• Collecting optimizing information after changing the collection level
• Registering a parameter file that contains optimized information in which different parameters are described

The following table shows combinations of pdgetcst operations and whether the optimized information can be restored in each case.

Table 19-2 Combinations of pdgetcst operations and whether the optimized information can be restored

pdgetcst operation performed up to saving (1)	pdgetcst operation performed after saving (2)	Can it be restored?	Remarks
Optimizing information collection (-c lvl1)	Optimizing information collection (-c lvl1)	Y	None
	Optimizing information collection (-c lvl2)	N	Cannot be restored because (2) increases the amount of information to be registered.
	Optimizing information registration (-s)	N	Cannot be restored because (2) might increase the amount of information to be registered.
Optimizing information collection (-c lvl2)	Optimizing information collection (-c lvl1)	Y	None
	Optimizing information collection (-c lvl2)
	Optimizing information registration (-s)	N	Cannot be restored because (2) might increase the amount of information to be registered (such as optimizing information for a column for which no index is defined).
Optimizing information registration (-s)	Optimizing information collection (-c lvl1)	N	Cannot be restored because (2) might increase the amount of information to be registered.
	Optimizing information collection (-c lvl2)
	Optimizing information registration (-s) (registering only the same parameter as in (1))	Y	None
	Optimizing information registration (-s) (registering a parameter that is different from that in (1))	N	Cannot be restored because (2) might increase the amount of information to be registered.

Legend:

Y:

Can be restored using a saved parameter file that contains optimized information.

N:

Cannot be restored using a saved parameter file that contains optimized information.

To restore the optimizing information:

1. Use the pdgetcst -d command to delete the currently registered optimizing information.
2. Use the pdgetcst -s command to register the saved parameter file that contains optimized information.

When you restore optimizing information, only the optimizing information that has been saved as a backup is restored.