You can either use the sample job described here to define the transient data
intrapartition data set, or you can use the CICS®-supplied
job, DFHDEFDS. DFHDEFDS creates the DFHINTRA data set as one of the data sets for a CICS region.
The intrapartition data set must be big enough to hold all the data for intrapartition queues.
See Size of the intrapartition data set for more information.
Intrapartition data set restrictions:
An intrapartition data set used as a transient data queue must be associated with only one CICS region.
CICS stores the relative byte addresses (RBAs) of records
written to an intrapartition data set used as a transient data queue, and you must take care to
preserve the RBAs during any VSAM export or import operation on the data set.
Data can be corrupted or lost if you start CICS with the
wrong intrapartition data set; that is, a data set that contains data from another CICS region.
Data can be corrupted or lost if you use VSAM export or import services to increase the available
space by compressing the data set, or to increase the control interval size.
Do not use the extended addressing entry-sequenced data set (ESDS) format for an intrapartition
data set.
Procedure
If you are using the sample job to define the transient data intrapartition data set, perform the
following steps:
Decide if a single extent data set on a single volume is appropriate.
If you
define one extent on one volume, you might require a much larger data set than your average
requirements to cater for exceptional cases. You can define multiple extents or multiple volumes or
both for the data set. The job control statements in Figure 1 are for a single extent data set
defined on a single volume. That data set must be big enough to hold all your data. For more
information, see Defining data sets with multiple extents and volumes.
Specify a CONTROLINTERVALSIZE parameter that is large enough to hold
the longest data record, in addition to the 32 bytes that CICS requires for its own purposes. The maximum control interval size is 32
KB.
Space is allocated to queues in units of a control interval (CI). 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.
If you allocate space in records, rather than tracks or cylinders, you must specify a
RECORDSIZE value.
The value must be 7 bytes less than the
CONTROLINTERVALSIZE.
Add the data definition statement for the intrapartition data set to the CICS startup job stream.
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, as in the following example. In the example DD statement below,
the prefix of the data set reflects the release of CICS TS, and the release level is assumed to be
CICS TS6.2.
Sample job to define a transient data intrapartition data set
In Figure 1, the high level qualifier
(CICSTSnn.CICS) assumes the release level of CICS TS6.2. You must adapt it for your own
CICS release.
What to do next
Use the TD system initialization parameter to specify an appropriate number
of VSAM buffers and strings for the transient data intrapartition data set. CICS uses buffers to make control intervals from the data set available in CICS storage, and uses strings for VSAM I/O requests between a
buffer and the data set. Typically, the default setting of three buffers and three strings is
sufficient.