SET DISPATCHER

Change CICS dispatcher system information.

Read syntax diagramSkip visual syntax diagramSET DISPATCHER
 
                   .-----------------------------.
                   V                             |
>>-SET DISPATCHER----+-------------------------+-+-------------><
                     +-MAXJVMTCBS(data-value)--+
                     +-MAXOPENTCBS(data-value)-+
                     +-MAXSSLTCBS(data-value)--+
                     +-MAXXPTCBS(data-value)---+
                     +-MROBATCH(data-value)----+
                     +-PRTYAGING(data-value)---+
                     +-RUNAWAY(data-value)-----+
                     +-SCANDELAY(data-value)---+
                     '-TIME(data-value)--------'
 

Conditions: INVREQ, NOTAUTH,

Description

The SET DISPATCHER command allows you to change the values of some of the options that CICS dispatcher domain uses for task and TCB management.

These values are set initially by system initialization parameters, described in the CICS® System Definition Guide. System initialization parameters that correspond to those in this command have the same or similar names. Table 3 lists the exact correspondence.

Options

MAXJVMTCBS(data-value)
specifies, as a fullword binary value, the maximum number of J8 and J9 mode open TCBs that can exist concurrently in the CICS region. The value specified can be in the range 1 to 999. Within this limit, there are no constraints on how many of the TCBs in the JVM pool are J8 TCBs, and how many are J9 TCBs.

If you reduce MAXJVMTCBS from its previously defined value, and the new value is less than the number of open TCBs currently allocated, CICS detaches TCBs to achieve the new limit only when they are freed by user tasks. Transactions are not abended to allow TCBs to be detached to achieve the new limit.

If there are tasks queued waiting for a J8 or J9 mode TCB and you increase MAXJVMTCBS from its previously defined value, CICS attaches a new TCB to resume each queued task, up to the new limit.

MAXOPENTCBS(data-value)
specifies, as a fullword binary value, the maximum number of L8 Start of change and L9 End of changemode open TCBs that can exist concurrently in the CICS region. The value specified can be in the range 1 to 2000.

If you reduce MAXOPENTCBS from its previously defined value, and the new value is less than the number of open TCBs currently allocated, CICS detaches TCBs to achieve the new limit only when they are freed by user tasks. Transactions are not abended to allow TCBs to be detached to achieve the new limit.

If there are tasks queued waiting for an L8 Start of change or an L9 End of changemode TCB, and you increase MAXOPENTCBS from its previously defined value, CICS attaches a new TCB to resume each queued task, up to the new limit.

MAXSSLTCBS(data-value)
specifies, as a fullword binary value, the maximum number of S8 mode open TCBs that can exist concurrently in the CICS region. The value specified can be in the range of 1 to 1024.
Start of changeMAXXPTCBS(data-value) End of change
Start of changespecifies, as a fullword binary value, the maximum number of X8 and X9 mode open TCBs that can exist concurrently in the CICS region. The value specified can be in the range 1 to 999.

If you reduce MAXXPTCBS from its previously defined value, and the new value is less than the number of open TCBs currently allocated, CICS detaches TCBs to achieve the new limit only when they are freed by user tasks. Transactions are not abended to allow TCBs to be detached to achieve the new limit.

If there are tasks queued waiting for an X8 or an X9 mode TCB, and you increase MAXXPTCBS from its previously defined value, CICS attaches a new TCB to resume each queued task, up to the new limit.

End of change
MROBATCH(data-value)
specifies, as a fullword binary value, the number of events that must occur, from a list of MRO and DASD I/O events on which CICS is waiting, before CICS is posted explicitly to process them. The value must be in the range 1-255.
PRTYAGING(data-value)
specifies, as a fullword binary value, the rate at which CICS is to increase the priority of a task waiting for dispatch. CICS increases the task priority by 1 after each PRTYAGING milliseconds of wait time without a dispatch. The value must be in the range 0-65535.
RUNAWAY(data-value)
specifies, as a fullword binary value, the default for runaway task time. This global value for the CICS region is used for any task executing a transaction that does not specify an explicit runaway task time.

The value must be either zero, which means that runaway task detection is not required for tasks using the default value, or in the range 500-2700000. The value you supply is rounded down to the nearest multiple of 500.

SCANDELAY(data-value)
specifies, as a fullword binary value, the maximum number of milliseconds between a user task making a terminal I/O request and CICS dispatching the terminal control task to process it. This value is sometimes called the "terminal scan delay", and is set initially by the system initialization option ICVTSD. The value must be in the range 0-5000.
TIME(data-value)
specifies, as a fullword binary value, the maximum interval in milliseconds for which CICS gives control to the operating system if no tasks are ready for dispatch. This value is set initially by the ICV system initialization option and is sometimes called the "region exit time interval". The TIME value must be in the range 100-3600000 and must not be less than the SCANDELAY value. You can determine the current SCANDELAY value, if you are not setting it at the same time, with the INQUIRE DISPATCHER SCANDELAY command.

Conditions

INVREQ
RESP2 values:
5
TIME is not in the range 100-3600000.
6
The RUNAWAY value is out of range.
7
MROBATCH is not in the range 1-255.
13
TIME is less than SCANDELAY.
14
PRTYAGING is not in the range 0-65535.
15
SCANDELAY is not in the range 0-5000.
26
The MAXOPENTCBS value is less than the TCBLIMIT on the DB2CONN resource definition (when CICS is connected to DB2 Version 6 or later).
27
The MAXOPENTCBS value is out of range.
28
The MAXJVMTCBS value is out of range.
Start of change30End of change
Start of changeThe MAXSSLTCBS value is out of range.End of change
Start of change31End of change
Start of changeThe MAXXPTCBS value is out of range.End of change
NOTAUTH
RESP2 values:
100
The user associated with the issuing task is not authorized to use this command.
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