Introduction to CICS statistics

CICS® management modules control how events are managed by CICS. As events occur, CICS produces information that is available to you as system and resource statistics.

The resources controlled by CICS include files, databases, journals, transactions, programs, and tasks. Resources that CICS manages, and values that CICS uses in its record-keeping role, are defined in one of the following ways:

Statistics are collected during CICS online processing for later offline analysis. The statistics domain writes statistics records to a System Management Facilities (SMF) data set. The records are of SMF type 110, sub-type 002. Monitoring records and some journaling records are also written to the SMF data set as type 110 records. You might find it useful to process statistics and monitoring records together. For programming information about SMF, and about other SMF data set considerations, see the CICS Customization Guide.

Types of statistics data

CICS produces five types of statistics:

Interval statistics
Are gathered by CICS during a specified interval. You can change the interval value using the STATINT system initialization parameter, or using CEMT SET STATISTICS, or using the EXEC CICS SET STATISTICS command. CICS writes the interval statistics to the SMF data set automatically at the expiry of the interval if:
End-of-day statistics
Are a special case of interval statistics where all statistics counters are collected and reset. There are three ways to get end-of-day statistics: The end of day value defines a logical point in the 24 hour operation of CICS. You can change the end of day value using the STATEOD system initialization parameter, or using CEMT SET STATISTICS, or using the EXEC CICS SET STATISTICS command. End-of-day statistics are always written to the SMF data set, regardless of the settings of any of the following: The statistics that are written to the SMF data set are those collected since the last event which involved a reset. The following are examples of resets:

The default end-of-day value is 000000 (midnight).

End-of-day statistics are always written to the SMF data set, regardless of the settings of any of the following:

Requested statistics
are statistics that the user has asked for by using one of the following commands: These commands cause the statistics to be written to the SMF data set immediately, instead of waiting for the current interval to expire. The PERFORM STATISTICS command can be issued with any combination of resource types or you can ask for all resource types with the ALL option. For more details about CEMT commands see CICS Supplied Transactions; for programming information about the equivalent EXEC CICS commands, see the CICS System Programming Reference.
Requested reset statistics
differ from requested statistics in that all statistics are collected and statistics counters are reset. You can reset the statistics counters using the following commands:

The PERFORM STATISTICS command must be issued with the ALL option if RESETNOW is present.

You can also invoke requested reset statistics when changing the recording status from ON to OFF, or vice versa, using CEMT SET STATISTICS ON|OFF RECORDNOW RESETNOW, or EXEC CICS SET STATISTICS ON|OFF RECORDNOW RESETNOW.

Note:
It is valid to specify RECORDNOW RESETNOW options only when there is a genuine change of status from STATISTICS ON to OFF, or vice versa. In other words, coding EXEC CICS SET STATISTICS ON RECORDNOW RESETNOW when statistics is already ON will cause an error response.

RESETNOW RECORDNOW on the SET STATISTICS command can only be invoked if the RECORDING option is changed.

Note:
Issuing the RESETNOW command by itself in the SET STATISTICS command causes the loss of the statistics data that has been collected since the last interval. Interval collections take place only if you set the RECORDING status ON. To set the statistics recording status ON or OFF, use either the RECORDING option on this command or the SIT parameter STATRCD. Statistics are always written, and counts reset, at the end of day.

Unsolicited statistics
are automatically gathered by CICS for dynamically allocated and deallocated resources. CICS writes these statistics to SMF just before the resource is deleted regardless of the status of statistics recording.

Unsolicited statistics are produced for:

Autoinstalled terminals
Whenever an autoinstalled terminal entry in the TCT is deleted (after the terminal logs off), CICS collects statistics covering the autoinstalled period since the last interval. The period covers any delay interval specified by the system initialization parameter, AILDELAY.

If an autoinstall terminal logs on again before the expiry of the delay interval, the accumulation of statistics continues until the next interval. At that interval, the accumulation of statistics is restarted.

CorbaServer
Whenever a CorbaServer is discarded, CICS collects the statistics for that CorbaServer covering the period from the last interval.
DBCTL
Whenever CICS disconnects from DBCTL, CICS collects the statistics covering the whole of the DBCTL connection period.
DB2®
Whenever CICS disconnects from DB2, CICS collects the statistics for the DB2 connection and all DB2ENTRYs covering the period from the last interval.

Whenever a DB2ENTRY is discarded, CICS collects the statistics for that DB2ENTRY covering the period from the last interval.

FEPI connection
Unsolicited connection statistics are produced when a connection is destroyed. This could occur when a DISCARD TARGET, DISCARD NODE, DISCARD POOL, DELETE POOL, DISCARD NODELIST, or DISCARD TARGETLIST command is used.
FEPI pools
Unsolicited pool statistics are produced when a pool is discarded by using the DISCARD POOL or DELETE POOL command.
FEPI targets
Unsolicited target statistics are produced when a target is destroyed or removed from a pool. This occurs when a DELETE POOL, DISCARD POOL, DISCARD TARGET, or DISCARD TARGETLIST command is used.
Files
Whenever CICS closes a file, CICS collects statistics covering the period from the last interval.
Journalnames
Unsolicited journalname statistics are produced when a journalname is discarded by using the DISCARD JOURNALNAME command.
Logstreams
Unsolicited logstream statistics are produced when the logstream is discarded from the MVS™ system logger.
LSRpools
When CICS closes a file which is in an LSRpool, CICS collects the statistics for the LSRpool. The following peak values are reset at each interval collection:
  • Peak number of requests waiting for a string
  • Maximum number of concurrent active file control strings.

The other statistics, which are not reset at an interval collection, cover the entire period from the time the LSRpool is created (when the first file is opened) until the LSRpool is deleted (when the last file is closed).

Programs
When an installed program definition is discarded, CICS collects the statistics covering the installed period since the last interval.
Requestmodel
Whenever a Requestmodel is discarded, CICS collects the statistics for that Requestmodel covering the period since the last interval.
TCP/IP Services
Whenever CICS closes a TCP/IP service, CICS collects the statistics covering the period since the last interval.
Transactions
When an installed transaction definition is discarded, CICS collects the statistics covering the installed period since the last interval.
Transaction classes
When an installed transaction class definition is discarded, CICS collects the statistics covering the installed period since the last interval.
Transient data queues
Unsolicited transient data queue statistics are produced when a transient data queue is discarded by using DISCARD TDQUEUE, or when an extrapartition transient data queue is closed.
Note:
To ensure that accurate statistics are recorded unsolicited statistics (USS) must be collected. An unsolicited record resets the statistics fields it contains. In particular, during a normal CICS shutdown, files are closed before the end of day statistics are gathered. This means that file and LSRpool end-of-day statistics will be zero, while the correct values will be recorded as unsolicited statistics.

Resetting statistics counters

When statistics are written to the SMF data set, the counters are reset in one of the following ways:

For detailed information about the reset characteristics, see Appendix A. CICS statistics tables.

The arrival of the end-of-day time, as set by the ENDOFDAY parameters, always causes the current interval to be ended (possibly prematurely) and a new interval to be started. Only end-of-day statistics are collected at the end-of-day time, even if it coincides exactly with the expiry of an interval.

Changing the end-of-day value changes the times at which INTERVAL statistics are recorded immediately. In the example below, when the end-of-day is changed from midnight to 1700 just after 1400, the effect is for the interval times to be calculated from the new end-of-day time. Hence the new interval at 1500 as well as for the times after new end-of-day time.

When you change any of the INTERVAL values (and also when CICS is initialized), the length of the current (or first) interval is adjusted so that it expires after an integral number of intervals from the end-of-day time.

These rules are illustrated by the following example. I indicates an interval recording and E indicates an end-of-day recording.

Figure 2. Resetting statistics counters
 This CICS system is initialized with ENDOFDAY(000000) and INTERVAL(030000). The first interval recording is taken at 0900 hours. At 09.30, the systems administrator changes INTERVAL to 020000. The interval must expire after an integral number of intervals from the end-of-day time, which is currently set to midnight, so to achieve this, an interval recording is taken at 1000 hours. Following the new setting, further interval recordings are taken at 1200 hours and at 1400 hours. At 14.30, though, the systems administrator changes ENDOFDAY to 170000. The interval times are immediately recalculated from the new end-of-day time, and an interval recording is taken at 1500 hours, two hours from the end-of-day time. The end-of-day recording is taken at 1700 hours. The CICS system is left running, so further interval recordings are taken at 1900 hours and 2100 hours.

If you want your end-of-day recordings to cover 24 hours, set INTERVAL to 240000.

Note:
Interval statistics are taken precisely on a minute boundary. Thus users with many CICS regions on a single MVS image could have every region writing statistics at the same time, if you have both the same interval and the same end of day period specified. This could cost up to several seconds of the entire CPU. If the cost becomes too noticeable, in terms of user response time around the interval expiry, you should consider staggering the intervals. One way of doing this while still maintaining very close correlation of intervals for all regions is to use a PLT program like the supplied sample DFH$STED which changes the end-of-day, and thus each interval expiry boundary, by a few seconds. See the CICS Operations and Utilities Guide for further information about DFH$STED.

Setting STATRCD=OFF reduces the number of times that statistics are written to the SMF data set and the counters are reset to the end-of-day, unsolicited, and requested reset only."

Related reference
Processing CICS statistics
Interpreting CICS statistics
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