CICS: GETMAIN Vs FREEMAIN to Manage Storage

4 Most searched Technics on how to manage storage using GETMAIN and FREEMAIN commands in CICS.

1. CICS makes working storage available within each command-level program automatically, without any specific request from the application program, and provides other facilities for intermediate storage, both within and among tasks. Design for performance describes storage within individual programs. If you need working storage in addition to the working storage provided automatically by CICS, however, you can use the following commands:
   GETMAIN to get and initialize main storage
   FREEMAIN to release main storage
2. You can initialize the acquired main storage to any bit configuration by supplying the INITIMG option on the GETMAIN command; for example, zeros or EBCDIC blanks. CICS releases all main storage associated with a task when the task is ended normally or abnormally. This includes any storage acquired, and not subsequently released, by your application program, except for areas obtained with the SHARED option. This option of the GETMAIN command prevents storage being released automatically when a task completes.
3. If you use the GETMAIN command with the SHARED option, and the FREEMAIN command, you could create inter-transaction affinities that adversely affect the ability to perform dynamic transaction routing.
4. If there is no storage available when you issue your request, CICS suspends your task until space is available, unless you specify the NOSUSPEND option. While the task is suspended, it may be canceled (timed out) if the transaction definition specifies SPURGE(YES) and DTIMOUT(mmss). NOSUSPEND returns control to your program if storage is not available, allowing you to do alternative processing, as appropriate.

Keep Reading