CHOOSING A RECOVERY TECHNIQUE - IBM Mainframe

As you can see, there are many options available for implementing recovery in an application program. You should be aware that all the CICS provided recovery facilities are optional. Their availability depends on options selected during system installation. So the systems analysts should sit with the system programmers to chalk out a recovery strategy. Terminal users will normally need assistance after an abend has occurred to determine what he should do next. Procedures should be created to help users to get back onto the system.

As in all design choices, there are tradeoffs between using and not using recovery. On one hand, recovery processing places and additional burden on system resources. On the other hand some application functions may be essential to the effective performance of business. If a task fails and the system's integrity is not maintained inaccurate data could be used to make business decisions, which can have very nasty consequences.
So as an application designer you should try to minimize the amount of recovery processing that is performed for an application system. The following guidelines will help you to minimize recovery processing:

  • Perform recovery only for critical resources.
  • Avoid abnormal termination whenever possible by using HANDLE CONDITION, IGNORE CONDITION or NOHANDLE to handle non-critical processing errors.
  • Commit a unit of work as early as possible. This will reduce the amount of backout processing required for an abended task.
  • Use a program level abend exit, where possible, to determine if any modifications were made to recoverable resources. If none were made, the exit can normally terminate the task, avoiding additional abend processing.
  • Where appropriate, use a SYNCPOINT ROLLBACK option in a program level abend exit to back out modifications and return control so that task processing can continue without abending.
  • When you cannot provide abend exit processing to handle an error correctly, let DTB in conjunction with any CICS exits supplied by your installation, restore modified resources to their state prior to the current LUW.

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