Managing 64-bit addressing with MEMLIMIT

The IMS HP Change Accumulation Utility MEMLIMIT command specifies the upper limit of storage above the bar that will be used by IMS HP Change Accumulation Utility for spill file data in memory. IMS HP Change Accumulation Utility commands are read from the HPCSYSIN DD.

The following conditions apply when using the IMS HP Change Accumulation Utility MEMLIMIT command:

• The limit value is always given in units of 1 megabyte (1024MB = 1GB).
• The limit can be less than the system MEMLIMIT value to reserve memory above the bar.
• The IMS HP Change Accumulation Utility MEMLIMIT command is supported in both multiple address space mode and single address space mode.
• In single address space mode, the IMS HP Change Accumulation Utility cache manager overrides the IMS HP Change Accumulation Utility MEMLIMIT command.

For example, the MEMLIMIT value set in the following HPCSYSIN DD limits IMS HP Change Accumulation Utility use of above the bar memory to 4GB:

//HPCSYSIN DD  *                                                        00470013 
      ID                 = CA14                                         00480013 
      List                                                              00490013 
      Unit               = 3390                                         00500013 
      MAXIMUM LOGS       = 118                                          00510013 
      PARALLEL LOGS      = 5                                            00520020 
      PARALLEL SORTS     = 7                                            00530013 
      Procedure Name     = HPCSTASK                                     00540020 
      Spill BLKSIZE      = 26624                                        00550013 
      Select Logs        = PRILOG                                       00560013 
      MEMLIMIT           = 4096                                         00570020