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:
- Online, by the CICS CEDA transaction.
- Offline, by the CICS system definition (CSD) utility program, DFHCSDUP.
See the CICS Customization Guide for programming information about
DFHCSDUP.
- Offline, by CICS control table macros.
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.
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:
- Statistics recording status was set ON by the STATRCD system initialization
parameter (and has not subsequently been set OFF by a CEMT or EXEC CICS SET STATISTICS
RECORDING command). The default is STATRCD=OFF.
- ON is specified in CEMT SET STATISTICS.
- The RECORDING option of the EXEC CICS SET STATISTICS command is set to ON.
- 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 expiry time
- When CICS quiesces (normal shutdown)
- When CICS terminates (immediate shutdown).
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 system initialization parameter, STATRCD, or
- CEMT SET STATISTICS or
- The RECORDING option of EXEC CICS SET STATISTICS.
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:
- At CICS startup
- Issue of RESETNOW RECORDNOW in CEMT or EXEC CICS STATISTICS commands.
- Interval statistics
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:
- The system initialization parameter, STATRCD, or
- CEMT SET STATISTICS or
- The RECORDING option of EXEC CICS SET STATISTICS.
- Requested statistics
- are statistics that the user has asked for by using one of the following
commands:
- CEMT PERFORM STATISTICS RECORD
- EXEC CICS PERFORM STATISTICS RECORD
- EXEC CICS SET STATISTICS ON|OFF RECORDNOW.
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:
- CEMT PERFORM STATISTICS RECORD ALL RESETNOW
- EXEC CICS PERFORM STATISTICS RECORD ALL RESETNOW
- EXEC CICS SET STATISTICS ON|OFF RESETNOW RECORDNOW
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.
When statistics are written to the SMF data set, the counters are reset
in one of the following ways:
- Reset to zero
- Reset to 1
- Reset to current values (this applies to peak values)
- Are not reset
- Exceptions to the above.
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.
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."
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