CEMT SET SYSTEM

Change the CICS® system attributes.

CICS Explorer graphic In the CICS Explorer, the Regions operations view provides a functional equivalent to this command.

Syntax

Press the Clear key to clear the screen. You can start this transaction in two ways:

Type CEMT SET. The SYSTEM keyword is assumed as the default, so you do not need to type it. The resulting display lists the current status, similar to that obtained by using CEMT INQUIRE SYSTEM. You can then tab to the highlighted or blank fields and overtype them with the required values.
Type CEMT SET followed by one or more attribute settings that you want to change. For example, cemt set ag(value) ma(value) resets the values for priority aging and the maximum number of tasks allowed at any one time in the CICS system.

Typing ? at the beginning of either the first or second line gives a syntax prompt. Resetting the values takes effect immediately.


CEMT SET SYSTEM

                    .-------------------------.   
                    V                         |   
>>-CEMT SET SYSTEM----+---------------------+-+----------------><
                      +-AGING(value)--------+     
                      +-AKP(value)----------+     
                      +-+-DEBUG---+---------+     
                      | '-NODEBUG-'         |     
                      +-DSALIMIT(value)-----+     
                      +-DSRTPROGRAM(value)--+     
                      +-DTRPROGRAM(value)---+     
                      +-+-SYSDUMP---+-------+     
                      | '-NOSYSDUMP-'       |     
                      +-EDSALIMIT(value)----+     
                      +-+-FORCE---+---------+     
                      | '-NOFORCE-'         |     
                      +-LOGDEFER(value)-----+     
                      +-MAXTASKS(value)-----+     
                      +-MROBATCH(value)-----+     
                      +-+-CTLGALL----+------+     
                      | +-CTLGMODIFY-+      |     
                      | '-CTLGNONE---'      |     
                      +-PROGAUTOEXIT(value)-+     
                      +-+-AUTOACTIVE---+----+     
                      | '-AUTOINACTIVE-'    |     
                      +-RUNAWAY(value)------+     
                      +-SCANDELAY(value)----+     
                      '-TIME(value)---------'

Options

AGING (value)

Specifies the time factor for CICS to use in the priority aging algorithm to increment the priority of a task. The value is expressed as milliseconds per unit of priority, and must be in the range 0 - 65535. The priority aging factor is defined initially by the PRTYAGE system initialization parameter, in which the value represents the number of milliseconds that must elapse before the priority of a waiting task can be adjusted upward by 1. For more information about this parameter, see PRTYAGE .

AKP (value)

Specifies the activity keypoint trigger value, which is the number of write requests to the CICS system log stream output buffer between the taking of keypoints. The value can be zero, which turns activity keypointing off, or be in the range 50 - 65535. You cannot change this value if AKPFREQ=0 was specified at system initialization. End of change

AUTOACTIVE

Autoinstall for programs is active. On first use, if a program, map set, or partition set is not defined, the definition is created dynamically.

AUTOINACTIVE

Autoinstall is not active. If a program is not defined, a PGMIDERR or transaction abend occurs when it is referenced.

CTLGALL

All autoinstalled program definitions are cataloged and restored on a warm or emergency restart.

CTLGMODIFY

Autoinstalled program definitions are cataloged only if they are modified (for example, by a CEMT SET PROGRAM command), so that the modified definitions are restored on a warm or emergency restart.

CTLGNONE

No autoinstalled program definitions are cataloged. They are autoinstalled again after a warm or emergency restart.

DEBUG

Specifies that CICS debugging profiles can be used to select the programs that will run under the control of a debugging tool. The following debugging tools use debugging profiles:

Debug Tool, for compiled language application programs (programs written in COBOL, PL/I, C, C++, and Assembler)
Remote debugging tools (for compiled language application programs and Java™ programs)

Other debugging mechanisms, for example the CICS Execution Diagnostic Facility (CEDF), do not use debugging profiles.

For more information about debugging profiles, see Debugging profiles.

DSALIMIT (value)

Specifies the maximum amount of storage, as a total number of bytes, within which CICS can dynamically allocate storage for the four individual DSAs that reside below 16 MB (below the line). For more information, see DSALIM system initialization parameter. If this parameter specifies a value lower than the current limit, CICS might not implement the new limit immediately, but attempts to do so over time as dynamic storage is freed in the individual DSAs.

Note: Dynamic changes to the DSA limit are cataloged in the local catalog, and override values specified in the system initialization table during all forms of restart: initial, old, and warm. The cataloged value is not used if:

You specify startup values as system initialization parameters overrides (for example, in SYSIN).
You re-initialize the CICS catalog data sets.

Note: That while you are changing the DSA limits dynamically is possible, it is recommended that you do not do so unless you are addressing an urgent situation and are trying to avoid cycling the region. While your change to the DSA limits might be successful from the CICS perspective, increasing the limits can cause other problems because the larger DSA will no longer be contiguous. MVS™ allocates storage both from high private growing down, and low private growing up. Increasing the DSA limits dynamically will cause a new piece of storage that is allocated by CICS in the middle of the MVS private storage area. Depending on the MVS use of storage in this area, you might now be at increased risk of an S878 or S80A abend as a result.

Similarly, decreasing the DSA limits dynamically might indeed give back storage to MVS for use, but there is no certainty where the storage given back will be, and it most likely will not be in an area where MVS needed it.

Monitor CICS statistics regularly, and proactively adjust DSA limits, and MXT limits.

DSRTPROGRAM (value)

Specifies the name of the distributed routing program.

DTRPROGRAM (value)

Specifies the name of the dynamic routing program.

EDSALIMIT (value)

Specifies the maximum amount of storage, as a total number of bytes, within which CICS can dynamically allocate storage for the individual DSAs that reside above 16 MB but below 2 GB (above the line). For more information, see EDSALIM system initialization parameter. If EDSALIMIT specifies a value lower than the current limit, CICS might not implement the new limit immediately, but attempts to do so over time as dynamic storage is freed in the individual DSAs.

Note: Dynamic changes to the EDSA limit are cataloged in the local catalog, and override values specified in the system initialization table during all forms of restart: initial, old, and warm. The cataloged value is not used if:

You specify startup values as system initialization parameters overrides (for example, in SYSIN).
You re-initialize the CICS catalog data sets.

Note: That while you are changing the EDSA limits dynamically is possible, it is recommended that you do not do so unless you are addressing an urgent situation and are trying to avoid cycling the region. While your change to the EDSA limits might be successful from the CICS perspective, increasing the limits can cause other problems because the larger EDSA will no longer be contiguous. MVS allocates storage both from high private growing down, and low private growing up. Increasing the EDSA limits dynamically will cause a new piece of storage that is allocated by CICS in the middle of the MVS private storage area. Depending on the MVS use of storage in this area, you might now be at increased risk of an S878 or S80A abend as a result.

Similarly, decreasing the EDSA limits dynamically might indeed give back storage to MVS for use, but there is no certainty where the storage given back will be, and it most likely will not be in an area where MVS needed it.

Monitor CICS statistics regularly, and proactively adjust EDSA limits, and MXT limits.

FORCE

Force all CICSAPI user application programs to run under the QR TCB, even if they are defined with the CONCURRENCY(THREADSAFE) attribute. The FORCE option does not apply to certain programs, for example OPENAPI programs, or C or C++ programs compiled with XPLINK. For details, see FORCEQR system initialization parameter.

LOGDEFER (value)

Specifies the log deferral interval in milliseconds. This interval is the period of time used by CICS Log Manager to determine how long to delay a forced journal write request before invoking the MVS system logger. The value is in the range 0 - 65535. For more information, see LGDFINT system initialization parameter.

MAXTASKS (value)

Specifies the maximum number of tasks, both active and suspended, allowed at any one time in the CICS system. The value must be in the range 10 - 2000.

Note: The value assigned to MAXTASKS might be less than the requested value, because of CICS storage constraints. If this occurs, the message CEILING REACHED is displayed when the request is made.

MROBATCH (value)

Specifies the number of MRO requests from connected regions that are batched before this region is posted. The value must be in the range 1 - 255.

NODEBUG

Specifies that you do not want to use CICS debugging profiles to select the programs that will run under the control of a debugging tool. The following debugging tools use debugging profiles:

Debug Tool, for compiled language application programs (programs written in COBOL, PL/I, C, C++, and Assembler)
Remote debugging tools (for compiled language application programs and Java programs)

Other debugging mechanisms, for example the CICS Execution Diagnostic Facility (CEDF), do not use debugging profiles.

For more information about debugging profiles, see Debugging profiles.

NOFORCE

Do not force user application programs to run under the QR TCB. CICS honors the CONCURRENCY(THREADSAFE) attribute on user application programs, and allows user programs to run on an open TCB to avoid unnecessary TCB switching.

NOSYSDUMP

Specifies that system dumps are suppressed.

PROGAUTOEXIT (value)

Specifies the name of the user-provided program that the program autoinstall code calls to select or modify a model definition.

RUNAWAY (value)

Specifies the interval, in milliseconds, for which a task can have control before it is assumed to be looping.

You can specify 0, or a value in the range 500–2700000. The value chosen is rounded down to a multiple of 500. CICS purges a task if it has not given up control after this interval (that is, if the task appears to be looping). If you specify zero, runaway task control is inoperative (that is, tasks do not get purged if they appear to be looping). The value is independent of, and can be less than, the TIME value.

CICS runaway-task detection is based upon task time, that is, the interval is decremented only when the task has control of the processor. You do not, therefore, need to allow for the effect of other jobs when setting the value.

SCANDELAY (value)

Specifies the terminal scan delay value for the CICS region, which is initially set by the ICVTSD system initialization parameter. The default value is zero. The terminal scan delay facility was used in earlier releases to limit how quickly CICS dealt with some types of terminal output requests made by applications, in order to spread the overhead for dealing with the requests. Specifying a nonzero value was sometimes appropriate where the CICS system used non-SNA networks. However, with SNA and IPIC networks, setting ICVTSD to 0 is appropriate to provide a better response time and best virtual storage usage. If required, you can reset this value by overtyping it with a different value in the range 0–5000 milliseconds. End of change

SYSDUMP

Specifies that system dumps are not suppressed.

TIME (value)

Specifies the interval, in milliseconds, for which CICS releases control to the operating system if no transactions are ready to resume processing. This interval is known as the region exit interval.

The value can be in the range 100 - 3600000, and must be greater than or equal to the SCANDELAY value.

In the summary report of the dispatcher statistics, the TIME value is referred to as the ICV time value.

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Last updated: Thursday, 27 June 2019