Start of change

IMS Fast Monitor (FASTMON) user exit enhancement

IMS 15 introduces a new exit, the IMS Fast Monitor user exit (FASTMON), which provides a programming interface for you to capture the same data that is available to the IMS Monitor.

The new IMS Fast Monitor (FASTMON) user exit, like the IMS Monitor (IMSMON) user exit, provides access to the IMS Monitor data without the need to modify IMS code. However, the FASTMON exit is optimized to minimize performance overhead, in exchange for certain functional restrictions.

Compared to the IMSMON user exit, the FASTMON user exit:
  • Not refreshable;
  • Cannot use user exit callable services;
  • Has a simpler register interface.

The FASTMON user exit is called during IMS initialization, IMS termination, and at IMS monitor call points for registered SLOG codes, regardless of whether the IMS Monitor is on or off.

Restrictions

An exit must not modify any other places in the array except for moving a 'Y' in the slot that represents the SLOG codes that the exit is interested in. Because all exit routines for the IMSMON and FASTMON exit types are passed in the same array, making other changes to the slot might unregister another exit's interest in that SLOG code if that exit also puts a 'Y' there.

Changes to installing and defining IMS

The FASTMON user exit can be specified in the EXITDEF parameter in the USER_EXITS section of the DFSDFxxx member.

Changes to administering IMS

The FASTMON user exit provides a similar exit point as the IMSMON user exit does. When FASTMON and IMSMON user exits are both defined, all the FASTMON exits are called first in the order that is listed on the EXITDEF parameter before all the IMSMON exits being called.

Changes to troubleshooting for IMS

This enhancement introduces the following new or changed IMS messages:
  • DFS4570E
  • DFS4573E
  • DFS4588E (new)

For a list of the messages and codes that are new or changed for this enhancement, see the IMS messages and codes row in the table in Documentation changes.

For a complete list of all of the new, changed, and deleted messages, and abend codes in IMS 15, see Message and code changes in IMS 15.

Changes to commands

Support for the FASTMON exit type is added to the QUERY USEREXIT and REFRESH USEREXIT commands.

For a list of the commands that are new or changed for this enhancement see the IMS commands row in the table in Documentation changes.

Changes to exit routines

A new IMS Fast Monitor (FASTMON) user exit is introduced.

Support for the FASTMON exit type is added to the IMS Monitor (IMSMON) user exit because the FASTMON exit might affect some of the IMSMON exit's behaviors.

Documentation changes

The following table lists the publications that contain new or changed topics for the New function name enhancement. Publications that are not impacted by this enhancement are not included in the table.

Table 1. Links to topics that have new or changed content for this enhancement
Publication New or changed topics
Release planning
System definition
IMS messages and codes
IMS commands
Exit routines
End of change