Starting the Structure Alter Process

You can initiate structure alter processing either by using the IXLALTER macro or by issuing the SETXCF START,ALTER command. The IXLALTER macro allows an authorized user to request a change to the structure's size, entry-to-element ratio, and percentage of storage allocated for EMCs. The SETXCF START,ALTER command allows the operator to request a change only to the structure's size. Recall, however, that a request to contract the structure's size might also affect the entry-to-element ratio and the percentage of EMC storage.

XES determines if structure alter is supported by the current set of connectors to the structure. XES accepts the alter request if:
  • The structure to be altered is allocated in a coupling facility with the appropriate level (CFLEVEL=1 or higher for all structures, CFLEVEL=3 or higher for keyed list structures allocated with EMCs for which a change in size is requested, or CFLEVEL=4 for keyed list structures allocated with EMCs for which a change in the percentage of EMC storage is requested.
  • The structure is not already in an alter process.
  • The structure is not in a rebuild process, or in a user-managed duplexing rebuild process, or in the duplex established phase.
  • The SETXCF MODIFY command was NOT used to disable alter for the structure. Starting CF structure alter processing for such structures is not permitted.
  • The structure is persistent with no active or failed-persistent connectors.
  • The structure has active or failed-persistent connectors, all of whom specified ALLOWALTER=YES.
  • The structure is in the Duplex Established phase of user-managed duplexing rebuild or system-managed duplexing rebuild.
  • The structure has no objects in storage-class memory and no augmented space other than the fixed augmented space in use.