Exception processing modes

This section describes the three basic types of exception processing available: display exception processing, periodic exception processing, and exception event processing.

Display exception processing

Use display exception processing to monitor the occurrence of a specific exception. This exception processing mode operates in the foreground of Online Monitor processing. With display exception processing you can view thread activity exceptions, and statistics exceptions in interval or delta processing mode. See Statistics processing modes for an explanation of delta and interval processing.

With display exception checking, fields shown in the current panel are checked whenever the display is refreshed with new or historical data. Fields with exception conditions are shown in reverse video, and the color of the field indicates the level of the exception. Warning level exceptions are highlighted in yellow, while Problem level exceptions are highlighted in red. These colors can differ if you have changed your ISPF default colors. Selection fields in the detail panels are also shown in reverse video if any of their lower level windows contain fields in exception status. The exception notifications are stored and can be examined using the LOOK command.

Periodic exception processing

Use periodic exception processing to periodically monitor thread activity fields and statistics fields for exception conditions. This processing mode runs in the background of Online Monitor processing.

With periodic exception processing, data is tested for exception whenever the interval that you specified has elapsed (whether or not you are viewing the relevant data). If any Problem level exceptions are detected, the Exception Notification window is displayed. If only Warning level exceptions are detected, a message is displayed to notify that a periodic exception has occurred. This window is overlaid on the current panel and shows the number of periodic exceptions detected during the interval. The exception notifications are stored and can be examined using the LOOK command.

If the data collector is active, periodic exception processing can continue when you exit the Online Monitor. When you use the Online Monitor the next time, any periodic exceptions that were detected while you were not logged on are displayed. Periodic exception processing is not terminated until you stop it or until the data collector itself is terminated. If the data collector is not active, periodic exception processing terminates when you exit the Online Monitor.

Exception event processing

Use exception event processing to monitor the DB2® subsystem for the occurrence of particular events. This processing mode runs in the background of Online Monitor processing. The following events can be monitored:
  • Deadlock
  • Timeout
  • EDM pool full
  • Authorization failure
  • Thread commit indoubt
  • CF rebuild/alter start
  • CF rebuild/alter end
  • Global trace started
  • Data set extension
  • Unit of recovery problem
  • Log space shortage

The events must be specified with the EXCEPTIONEVENT data collector parameter or in the Data Collector Parameters window before exception event processing can be activated from the Exception Processor panel. For more information, see the IBM® Db2 for z/OS® in the IBM Knowledge Center.

When an exception event is detected, the Exception Notification window is displayed to notify you that an exception event has occurred. Exception event notifications are stored and can be examined using the LOOK command.

Past data and exceptions

Display exception processing operates with past data just as if the data had been retrieved directly from Db2. Exceptions are shown in reverse video and logged as normal.

Periodic exception processing and exception event processing do not report on past data. They report on current data, whether or not past data is currently being displayed.