The Create Data Queue (CRTDTAQ) command creates
a data queue and stores it in a specified library. Data queues are used to
communicate and store data used by several programs either within a job or
between jobs. Multiple jobs can send or receive data from a single queue.
The CRTDTAQ command can optionally create a
distributed data management (DDM) data queue. This is done by specifying *DDM
on the TYPE parameter. The DDM data queue is used as a reference data queue
by programs to access data queues located on a remote (target) server in the
DDM network. Programs on the local (source) server reference a remote data
queue by the DDM data queue's name, not by the remote data queue's name. (The
DDM data queue name, however, can be the same as the remote data queue name.)
The DDM data queue (on the source server) contains the name of
the remote data queue and the name of the remote (target) server on which
the remote data queue is located.
Consider the following items when using this command with DDM:
- The TYPE parameter specifies the type of data queue to be created. A standard
data queue or a DDM data queue can be created.
- The RMTDTAQ parameter is the name of the remote data queue on the target
system. The data queue does not need to exist when the DDM data queue is created.
- The RMTLOCNAME parameter is the name of the remote location that is used
with this object. Multiple DDM data areas can use the same remote location
for the target system. RMTLOCNAME must point to a target server that is an iSeries™ running at a release of i5/OS™ that supports remote data
areas. The possible values for RMTLOCNAME include:
- remote-location-name: Specifies the name of the remote
location that is associated with the target system. The remote location, which
is used in accessing the target system, does not need to exist when the DDM
data area is created, but it must exist when the DDM data area is accessed.
- *RDB: The remote location information for the relational database entry
specified in the relational database (RDB) parameter is used to determine
the remote system.
- The DEV parameter is the name of the APPC device description on the source
system that is used with this DDM data queue. The device description does
not need to exist when the DDM data queue is created.
- The LCLLOCNAME parameter is the local location name.
- The MODE parameter is the mode name that is used with the remote location
name to communicate with the target system.
- The RMTNETID parameter is the remote network ID in which the remote location
resides that is used to communicate with the target system.
Consider the following restrictions when using this command with
DDM:
- Only the API interface for data queues is supported when using DDM data
queues. The following APIs are supported:
- Send to Data Queue (QSNDDTAQ)
- Receive from Data Queue (QRCVDTAQ)
- Clear Data Queue (QCLRDTAQ)
The Retrieve Data Queue Description (QMHQRDQD) and Retrieve
Data Queue Messages (QMHRDQM) APIs are not supported for DDM data
queues. When using the *ASYNC parameter on the Send Data Queue API,
messages resulting from errors encountered when accessing the remote data
queue are placed in the target server's job log, and a DDM protocol error
(CPF9173 - Error detected in DDM data stream by target server)
is posted in the source system's job log. Look in the target server's job
log for the cause of the error and correct the problem before using the remote
data queue. Attempts to access the remote data queue after you receive this
error message without first correcting the problem will produce unpredictable
results.
- You cannot create a data queue remotely. This function can be done remotely
by using the Submit Remote Command (SBMRMTCMD) command.