CICS TDQCICS Queue CICS WRITE TDQ
Temporary Data Queues can only read once.
Records in TDQ can be read sequentially.
TDQ is read destructive.
Data will be erased from the queue once the record read in the application program.
Record in a TDQ cannot be updated.
TDQs name must first be defined in the DCT (Destination Control Table).
TDQ may be used by batch application.
TDQ can trigger a CICS transaction automatically.
This will trigger a transaction which does the printing.
If trigger level have n, after nth record is written to a TDQ it will automatically triggers the transaction associated with it.
This will call as ATI (Automatic Task Initialization).
TDQ has to be defined prior to use.
TDQ is written to Disk.
Transient data is always associated with destination.
TDQ to accumulate records before processing or send data for external use, such as a print operation or other.
There are two types of TDQ’s
1. Intrapartition transient data queue
2. Extra partition transient data queue
Intrapartition transient data queue:
Intra partition tdq is read destructive.
Application programs use intrapartition destinations to queue.
Intra partition tdq is stored in one physical file.
Data can be processed by other programs that are running as separate tasks within the same CICS region.
Data that is directed to or from these internal destinations is called intrapartition data.
APP PROGRAM access the intra partition tdq records sequentially after the records logically deleted from the queue.
Typical uses for intrapartition destinations include message switching, distribution of output to several terminals, and enqueueing data to assign priority by arrival.
Extra partition transient data queue:
Extra partition tdq is a group of sequential records which can be produced and processed outside the cics region
Extra partition destinations are queues that are residing on any file system file.
Extra partition tdq is not read destructive.
Data accessible by programs on any CICS region.
Data can also be routed to output devices, such as printers.
In general, extra partition destinations are used for storing and retrieving data outside the CICS region and for storing data for input to non-CICS programs.
Extra partition data consists of sequential records that are fixed length or variable length, as predefined for the destination.
The queue definition also defines the logical organization of records that are in the queue.
Each extra portion tdq record is stored in separate physical file.
The below operations can be performed on TDQ to store and process the data between transactions.
- WRITEQ TD
- READQ TD
- DELETE TD
Write data to transient data queue.
WRITEQ TD can be explained here.
Used to read data from the transient data queue.
READQ TD can be explained here.
Delete all transient data in the queue.
DELETEQ TD can be explained here.
If any questions on the above, post your queries on CICS Discussion forum
CICS Queue CICS WRITE TDQ