If the number of groups to be grouped is high, the rapid grouping facility may not be effective. If this is the case, specify a value of the required size (number of groups or higher) in the PDAGGR operand of the client environment definitions. Note, however, that a large amount of process-specific memory may be used. If the amount of memory used is large and a value of the required size cannot be specified, specify the maximum specifiable value that is less than the number of groups. Specifying a value larger than the number of groups is no more effective than specifying a value equal to the number of groups. For details about the PDAGGR operand, see 6.6.4 Environment definition information.