Controlling Dynamic Plan Selection

CA Datacom CICS Services provides the capability to dynamically select plans when running an application program in the CICS environment. Plan selection starts at the beginning of each logical-unit-of-work (LUW) and is controlled by values specified in the Dynamic Plan Selection Table. You create the table by specifying parameter values to the CA Datacom CICS Services DCPLAN macro and then assembling the macro specifications. The table must be named DCTABPR for which a sample is delivered to you. For more information, see Sample JCL for Dynamic Plan Selection Table Assembly.

Dynamic plan selection is implemented by replacing the AUTHID value associated with the plan. The substitution value is provided in the Dynamic Plan Selection Table. For example, if transaction ABCD is set (based on precompile values) to access plan PROD01.PLAN1 (AUTHID=PROD01,PLAN=PLAN1), and there exists an entry in the Dynamic Plan Selection Table for transaction ABCD, if the FROM AUTHID clause specifies PROD01, the AUTHID value is changed to reflect the value specified in the TO AUTHID clause.

CA Datacom CICS Services builds two sets of index tables after completing the Dynamic Plan Selection Table. The first index table built is for a transaction without a wildcard character specified. The second index table built is for a transaction with a wildcard character specified. CA Datacom CICS Services first uses a binary search to look for a match in the first index table. If the transaction ID is not found in the first index table, CA Datacom CICS Services uses a sequential search to scan the second index table. If the transaction ID or authorization ID is not defined in the Dynamic Plan Selection Table, CA Datacom CICS Services leaves the original authorization ID intact.

See also the descriptions of the DBCVTPR parameters AUTHID= and PLANSWI=. The DBCVTPR AUTHID= parameter allows you to specify a system-level AUTHID. The DBCVTPR PLANSWI= parameter controls whether dynamic plan selection facilities are invoked.

This section contains the following topics:

DCPLAN Macro Parameters

Dynamic Plan Selection Exit Routines