You use job control statements to define the transient data intrapartition data set, which must be big enough to hold all the data for intrapartition queues. You can define the data set as any one of the following:
Figure 5 shows job control statements to define a single extent data set on a single volume. Instead of defining one extent data set, which might have to be much larger than your average needs to cater for exceptional cases, you can define multiple extents and/or multiple volumes. For considerations about using multiple extents and/or multiple volumes, see Using multiple extents and multiple volumes.
//DEFDS JOB accounting info,name,MSGCLASS=A
//TDINTRA EXEC PGM=IDCAMS
//SYSPRINT DD SYSOUT=A
//SYSIN DD *
DEFINE CLUSTER -
( NAME(CICSTS31.CICS.applid.DFHINTRA) -
RECORDSIZE(1529,1529) -
RECORDS(100) -
NONINDEXED -
CONTROLINTERVALSIZE(1536) -
VOL(volid)) -
DATA -
( NAME(CICSTS31.CICS.applid.DATA.DFHINTRA))
/*
//
For an example of the JCL that you can use to define the transient data intrapartition data set, see Figure 5. If you allocate space in records, rather than tracks or cylinders, you need RECORDSIZE, and it should be 7 bytes less than the CONTROLINTERVALSIZE. (For full details, see the appropriate VSAM manuals.)
Alternatively, you can run the CICS-supplied job DFHDEFDS to create the DFHINTRA data set as one of the data sets for a CICS® region. For information about the DFHDEFDS job, see the CICS Transaction Server for z/OS® Installation Guide.
The DFHINTRA data set is opened during CICS initialization, regardless of the presence (or absence) of any intrapartition queue definitions that might become active during GRPLIST installation. If DFHINTRA fails to open during an initial or cold start of CICS, a message is issued informing you of this, and asking you if you wish to continue or if you wish to cancel CICS.
If DFHINTRA opened successfully during a previous startup but fails to open during a subsequent warm or emergency restart, CICS is terminated.
If CICS initializes without a DFHINTRA data set, any attempts to install intrapartition data destinations for that run of CICS fails and appropriate error messages are issued.
The job control statements in Figure 5 are for a single extent data set defined on a single volume. That data set must be big enough to hold all your data. Instead of defining one data set, which might have to be much larger than your average needs to cater for exceptional cases, you can define multiple extents and multiple volumes. For more information about defining these, see Multiple extents and multiple volumes.
Space is allocated to queues in units of a control interval. The first CI is reserved for CICS use, the remaining CIs are available to hold data. Data records are stored in CIs according to VSAM standards.
The CONTROLINTERVALSIZE parameter must be large enough to hold the longest record, plus the 32 bytes that CICS requires for its own purposes. The maximum control interval size is 32KB.
A transient data intrapartition data set should be associated with one, and only one, CICS region. (If you are running CICS with XRF, one region means a pair of active and alternate CICS regions.) The destination control table contains relative byte addresses (RBAs) of records written to an intrapartition data set, and care must be taken to preserve the RBAs during any VSAM export or import operation on the data set.
Data can be corrupted or lost if:
You can use the TD system initialization parameter to specify the number of CICS transient data buffers up to the maximum of 32 767. The number of buffers that you specify may have an effect on CICS performance, as described in Performance considerations of TS and TD buffers. You should specify a value to suit your CICS region.
The DD name for the intrapartition data set is DFHINTRA, and the DSN operand must be the name of the VSAM entry-sequenced data set. For a CICS execution, you need a data definition statement such as:
//DFHINTRA DD DSNAME=CICSTS31.CICS.applid.DFHINTRA,DISP={OLD|SHR}
A transient data intrapartition data set is a passively shared data set, owned by the active CICS region, but allocated to both active and alternate CICS regions.
Although the alternate CICS region does not open this data set before takeover, it is allocated at job step initiation, therefore specify DISP=SHR on the DD statement.
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