Dynamic changes to structure sizes

If the affected structure is allocated in a coupling facility with CFLEVEL greater than 0, you can dynamically increase the structure sizes up to a maximum limit specified on the CFRM policy by using the z/OS® command SETXCF START,ALTER.

The advantages to this method are:
  • Db2 can access the structures while a change is taking place.
  • Less coupling facility storage is required because Db2 does not need to allocate enough space for a whole new structure. It dynamically adds or deletes storage from the existing structure.
  • The command works on duplexed structures.