You can use transient data queues for many of the same
purposes as an auxiliary temporary storage queue.
Like temporary storage, intrapartition transient data consists
of data queues in a single data set with an index in main storage.
Transient data queues differ from auxiliary temporary storage queues
in the following ways:
- Transient data queue names must be defined in the RDO TDQUEUE
entry before CICS® is started.
Transient data queues do not have the same random access characteristics
as temporary storage queues.
- Transient data queues must be read sequentially, and each item
can be read only once. After a transaction reads an item, the item
is removed from the queue and is not available to any other transaction.
- Items in a transient data queue cannot be changed.
- Transient data queues are always written to a data set.
- Writing items to a transient data queue can initiate a specific
transaction when the trigger level for the queue is reached.
- A transient data queue can be physically or logically recoverable,
and you can specify that you want areas of the entry sequenced data
set (ESDS) that have been written and read to be reused for new data.
- You can direct print output to a transient data queue but not
to a temporary storage queue.
- Because the commands for intrapartition and extrapartition data
sets are the same, you can switch between the internal CICS facility and an external data set. You
need change only the RDO TDQUEUE entry.
Accessing tranisent data queues from EGL
An
EGL program generated for the CICS environment
can access CICS transient data
queues as a serial record. The following I/O statements are valid
when you access a transient data queue:
The resource association for the file must have the EGL
file type specified as transient when the
program is generated. The system resource name (systemName property)
is the name of the transient data queue as it is defined in the corresponding
TDQUEUE entry.
You can also use the resource association to
direct print output to a transient data queue.