5. FILES › 5.3 IDMS Information Area Files › 5.3.5 IDMS System Activity File (IDMSSY) › 5.3.5.3 Usage Considerations

5.3.5.3 Usage Considerations

This section identifies usage considerations and techniques
for accessing the IDMS System Activity File (IDMSSY).

Retained elements, as identified in the element list, are
only accurate in the DETAIL timespan.  They may be of value
in summarized timespans, but the user should be aware that
they lose significance after summarization.

Using the special date and time data elements requires
special care.  As the file's granularity increases in higher
timespans, certain fields lose significance and should not be
used, namely:

o  HOUR should not be used in MONTHS or YEARS.
o  DAY and DAYNAME should not be used in MONTHS or YEARS.
o  WEEK should not be used in MONTHS.

The data elements STARTTS and ENDTS have different meanings
when used in the DETAIL timespan versus their meanings in the
DAYS, WEEKS, MONTHS, and YEARS timespans.  In the DETAIL
timespan, STARTTS indicates the earliest date and time, while
ENDTS indicates the latest date and time, for the summarized
data.  In the DAYS, WEEKS, MONTHS, and YEARS timespans, both
STARTTS and ENDTS denote the span of time over which data
have been summarized.

In the DETAIL timespan, timestamps are calculated based on
the value you code in the INTERVAL statement of
prefix.MICS.PARMS(IDMOPS).  This value determines the cut-off
point for each timespan.  The start time is synchronized each
hour to provide continuity in timing, similar to the way that
IBM's Resource Management Facility (RMF) synchronizes time.

For example, if the interval specified is 600 seconds (10
minutes), the first and last intervals might be short but the
intervals in between will fall on even 10 minute boundaries
within the hour.

If the IDMSSY file is turned off in the DAYS timespan and you
have the DAYS timespan of the IDMSCL file turned on, your
IDMCGEN will fail.  This will occur because the IDMSCL file
is dependent upon the DAYS timespan of this file.  In order
to correct the problem, you must either turn the IDMSSY file
back on in the DAYS timespan or turn off the IDMSCL file in
the DAYS timespan.  If changes were made, you will need to
rerun the IDMCGEN job.

The DURATION data element represents the elapsed time of the
individual transaction records in the IDMSSY file.  In
summarized timespans, DURATION represents the sum of DURATION
of the individual transaction records that contributed to the
summarized observation.  DURATION is calculated as the
difference between the End Time (PMHETIME) and the Start Time
(PMHSTIME) fields from the CA-IDMS Performance Monitor header
record.

In all IDMS Analyzer files except the IDMSIN file, the
STARTTS and ENDTS data elements do not reflect the Start Time
and End Time of the individual transactions.  Instead,
STARTTS and ENDTS are adjusted to represent the start and end
of the time interval within which the transactions executed.