10. MODIFICATION › 10.2 Standard User Exits
10.2 Standard User Exits
Before implementing an exit, determine whether the required
modification can be accomplished by parameter modification or
file tailoring.
At times, additional system customization is needed to tailor
CA MICS to your site. There are many user exit points
provided within CA MICS. Each of these points corresponds to
a position in the CA MICS logic where user modification:
o Is likely to occur, based on our experience
o Presents only a slight possibility of compromising the
CA MICS database or operational integrity
o Is relatively easy to document and understand
Using the CA MICS exit facilities to augment CA MICS
processing logic is the safest method of system modification.
Generally, you have four methods with which to augment,
change, and enhance CA MICS.
o CA MICS standard option and parameter definitions
The diverse installation and definition options provide
most users with adequate provisions for customizing
CA MICS.
o Modification through user exits
Often there may be site-dependent requirements that are
not adequately addressed through the standard options
and parameters. In these cases, one or more of the
user exits provided with CA MICS may be used to insert
user-written routines that satisfy the requirements.
o Extension through field developed applications
Although most users do not initially consider this a
way of modifying a standard CA MICS product, the
development of field developed applications may be the
most advantageous method. For example, often it may be
better to write a field developed application to handle
additional SMF data than to attempt to modify the logic
of the CA MICS DB2 Analyzer.
o System code modification
As a final option, you may be able to satisfy your
site's requirements by implementing a source code
change.
GENERAL EXIT CONSIDERATIONS
You should carefully explore whether you need to develop a
user exit routine. First, ensure that the requirement cannot
be satisfied through one of the standard options or
definitions by discussing your requirement with CA Technical
Support.
Designing, coding, testing, and implementing a CA MICS user
exit routine should be done carefully, since any resulting
errors may corrupt the data. You should be meticulous in the
definition and validation of the exit routines to ensure that
system integrity and performance are not adversely affected.
If an exit must be used, refer to Chapter 9 of this guide for
a description of the location of the exit in the DAILY
update. For a better understanding of CA MICS user exits,
see Section 4.3 of the System Modification Guide.
Product exits are classified according to their purpose and
include product input, output, parameter-related, and
accounting exits. Input exits are invoked as the raw input
records are read. Output exits are invoked just before
CA MICS writes an observation to the CA MICS database.
The DB2 Analyzer provides the input exit _USRSEL. You can
use this exit to select or exclude input data that meets
special site-defined criteria, add data elements, or modify
record fields as they are read.
One output exit routine is provided for each product file.
You can use this output exit routine to selectively block the
writing of specified records, alter data elements in the
records, or produce additional records for the target file or
a user-defined file.
The product parameter-related exits are also user exits, but
they are defined as part of the standard CA MICS installation
process. They are normally associated with other parameters
or options. For example, the Account Code Derivation Routine
is a user exit routine for completing values for account
codes that were defined in the separate but related DB2ACRT
member of sharedprefix.MICS.PARMS. DB2ACRT is the Account
Code Definition parameter member. These exits are identified
in this chapter, but they are described in detail in Chapter
7.
The user exits for the DB2 Analyzer are discussed in detail
in the following sections:
1 - Input Exits
2 - Parameter-Related Exits
3 - Output Exits
