MQCONN attributes

Describes the syntax and attributes of the MQCONN resource.

Read syntax diagramSkip visual syntax diagramMQCONN( name)GROUP( groupname)DESCRIPTION( text)INITQNAME( name)MQNAME( name)RESYNCMEMBER(YES)RESYNCMEMBER(NO)RESYNCMEMBER(GROUPRESYNC)

Attributes

DESCRIPTION(text)
In this field, you can provide a description of the resource that you are defining. The description text can be up to 58 characters in length. No restrictions apply to the characters that you can use. However, if you use parentheses, ensure that each left parenthesis has a matching right one. If you use the CREATE command, for each single apostrophe in the text code, use two apostrophes.
GROUP(groupname)
Every resource definition must have a GROUP name. The resource definition becomes a member of the group and is installed in the CICS system when the group is installed.
Acceptable characters: 
A-Z 0-9 $ @ #
Any lowercase characters that you enter are converted to uppercase.

The GROUP name can be up to 8 characters in length.

INITQNAME(name)
Specifies the 1 - 48 character name of the default initiation queue for this CICS®-MQ connection.
Acceptable characters: 
A-Z a-z 0-9 . / _ %

When you specify the INITQNAME attribute, you can use a symbolic parameter, &APPLID., to identify the APPLID of a CICS region; for example, &APPLID..EXAMPLE.QUEUE.NAME. When you install the resource in a CICS region, &APPLID. is replaced with the APPLID of the local region.

When you install the MQCONN resource definition, if you specify a non-blank INITQNAME attribute, CICS installs an MQMONITOR resource with the reserved name of DFHMQINI representing the default initiation queue. The QNAME attribute of DFHMQINI specifies the default initiation queue name. If you want to change the QNAME attribute, you must change the INITQNAME attribute of the MQCONN resource definition and then reinstall the MQCONN resource definition.

When you start the CICS-MQ connection by using the CKQC START command, if you specify the name of a default initiation queue, the INITQNAME value of the installed MQCONN resource definition and the QNAME value of the installed MQMONITOR resource definition are replaced with the settings that you specify.

MQCONN(name)
Specifies the 8-character name of this resource definition.
Acceptable characters: 
A-Z 0-9 $ @ #
Unless you are using the CREATE command, any lowercase characters that you enter are converted to uppercase.
MQNAME(name)
Specifies the 1 - 4 character name of either a single IBM® MQ queue manager, or a queue-sharing group of IBM MQ queue managers.
  • If you specify a single queue manager, when you start the CICS-MQ connection, CICS connects only to this queue manager.
  • If you specify a queue-sharing group, when you start the connection, CICS connects to any active member of this group on the same LPAR. Use the RESYNCMEMBER attribute to specify what happens when CICS is holding outstanding units of work for the last queue manager to which it connected from the queue-sharing group.
  • If you specify RESYNCMEMBER(GROUPRESYNC), MQNAME must be the name of a queue-sharing group.
Acceptable characters: 
A-Z 0-9 $ @ #

The name of the queue manager or queue-sharing group must not start with a numeric character.

IBM MQ uses the @ symbol to pad queue-sharing group names that are less than four characters long. When you specify a queue-sharing group that is less than four characters long, do not include the @ symbols at the end; CICS adds the padding before querying the queue-sharing group. For example, if the queue-sharing group is defined to IBM MQ as DEV@, specify DEV as the value of the MQNAME attribute.

If you specify the name of an alternative IBM MQ queue manager or queue-sharing group on the CEMT or EXEC CICS SET MQCONN command, or specify a queue manager name when you start the CICS-MQ connection by using the CKQC START command, CICS connects to that alternative queue manager or queue-sharing group. In addition, your setting for the MQNAME attribute in the installed MQCONN definition is replaced with the name of the queue manager or queue-sharing group that you specified on the command. If you want to revert to the original queue manager or queue-sharing group, set MQNAME again.

RESYNCMEMBER({YES|NO|GROUPRESYNC})
This attribute applies only if you use the MQNAME attribute to specify an IBM MQ queue-sharing group. RESYNCMEMBER specifies the strategy that CICS adopts if outstanding units of work are being held for the last queue manager to which CICS was connected from the queue-sharing group.

Changing the setting for RESYNCMEMBER must be done only when all resources are in a consistent state; that is, there are no indoubt units of work outstanding otherwise CICS is not able to resynchronize the IBM MQ units of work. It is important to ensure that all resources are in a consistent state before changing RESYNCMEMBER to or from GROUPRESYNC.

YES
CICS connects to the same queue manager, waiting, if necessary, until the queue manager becomes active to resolve the indoubt units of work. YES is the default.
NO
CICS makes one attempt to connect to the same queue manager. If that attempt fails, CICS connects to any member of the queue-sharing group and issues the warning message DFHMQ2064 about the outstanding units of work.
GROUPRESYNC
CICS connects to any member of the queue-sharing group. The queue manager is chosen by IBM MQ and it asks CICS to resolve indoubt units of work on behalf of all eligible queue managers in the queue-sharing group. This function is called group unit of recovery. The GROUPRESYNC option can be used only when you are running WebSphere® MQ 7.1, or higher, that supports group unit of recovery for CICS and when group unit of recovery is enabled in the queue managers.

The main use of the GROUPRESYNC option is with shared queues, but it can be used with private queues. Messages on shared queues are resolved immediately, but resolution of private queues occurs when the owning queue manager restarts. If using private queues, it can be convenient to define the queues with QSGDISP(GROUP). QSGDISP(GROUP) ensures that an instance of the private queue exists on every manager in the queue sharing group, so that in the event of failure and reconnection to a different queue manager, the application can continue using the new queue instance. The application would need to be able to tolerate using a new queue instance.

Do not change the setting for RESYNCMEMBER when units of work are outstanding in IBM MQ, because units of work cannot be resolved. A unit of work held in CICS is identified with a resource manager qualifier. When RESYNCMEMBER(GROUPRESYNC) is used the qualifier is the name of the queue-sharing group, otherwise the qualifier used is the name of the individual queue manager.

Units of work that are shunted indoubt are not included in this process, because CICS itself cannot resolve those units of work at this time. Resynchronization for those UOWs occurs when CICS has resynchronized with its remote coordinator.