Attributes for queues

Use this information to learn about the different types of queue definitions and the attributes supported by each.

Types of queue: The queue manager supports the following types of queue definition:

    Local queue
    This is a physical queue that stores messages. The queue exists on the local queue manager.

    Applications connected to the local queue manager can place messages on and remove messages from queues of this type. The value of the QType queue attribute is QTLOC.

    Shared queue
    This is a physical queue that stores messages. The queue exists in a shared repository that is accessible to all of the queue managers that belong to the queue sharing group that owns the shared repository. Applications connected to any queue manager in the queue sharing group can place messages on and remove messages from queues of this type. Such queues are effectively the same as local queues. The value of the QType queue attribute is QTLOC.

    • Shared queues are supported only on z/OS .

    Cluster queue
    This is a physical queue that stores messages. The queue exists either on the local queue manager, or on one or more of the queue managers that belong to the same cluster as the local queue manager.

    Applications connected to the local queue manager can place messages on queues of this type, regardless of the location of the queue. If an instance of the queue exists on the local queue manager, the queue behaves in the same way as a local queue, and applications connected to the local queue manager can remove messages from the queue. The value of the QType queue attribute is QTCLUS.

    Alias queue
    This is not a physical queue - it is an alternative name for a local queue. The name of the local queue to which the alias resolves is part of the definition of the alias queue.

    Applications connected to the local queue manager can place messages on and remove messages from alias queues - the messages are placed on and removed from the local queue to which the alias resolves. The value of the QType queue attribute is QTALS.

    Remote queue
    This is not a physical queue - it is the local definition of a queue that exists on a remote queue manager. The local definition of the remote queue contains information that tells the local queue manager how to route messages to the remote queue manager.

    Applications connected to the local queue manager can place messages on remote queues - the messages are placed on the local transmission queue used to route messages to the remote queue manager. Applications cannot remove messages from remote queues. The value of the QType queue attribute is QTREM.

    A remote queue definition can also be used for:

    Model queue
    This is not a physical queue - it is a set of queue attributes from which a local queue can be created.

    Messages cannot be stored on queues of this type.

Some queue attributes apply to all types of queue; other queue attributes apply only to certain types of queue. The types of queue to which an attribute applies are indicated by an "X" in Table 1 and subsequent tables. Table 1 summarizes the attributes that are specific to queues. The attributes are described in alphabetical order.

The names of the attributes shown in the table are the names used with the MQINQ and MQSET calls. When MQSC commands are used to define, alter, or display attributes, alternative short names are used; see MQSC commands for details.

In the following table, the columns apply as follows:

  • The column for local queues applies also to shared queues.
  • The column for model queues indicates which attributes are inherited by the local queue created from the model queue.
  • The column for cluster queues indicates the attributes that can be inquired when the cluster queue is opened for inquire alone, or for inquire and output. If the cluster queue is opened for inquire plus one or more of input, browse, or set, the column for local queues applies instead.

Attribute Description Local Model Alias Remote Cluster
AlterationDate Date when definition was last changed X X X
AlterationTime Time when definition was last changed X X X
BackoutRequeueQName Excessive backout requeue queue name X X
BackoutThreshold Backout threshold X X
BaseQName Queue name to which alias resolves X
ClusterChannelName Cluster-sender channel name      
ClusterName Name of cluster to which queue belongs X X X
ClusterNamelist Name of namelist object containing names of clusters to which queue belongs X X X
CreationDate Date the queue was created X
CreationTime Time the queue was created X
CurrentQDepth Current queue depth X
DefBind Default binding X X X X
DefinitionType Queue definition type X X
DefInputOpenOption Default input open option X X
DefPersistence Default message persistence X X X X X
DefPriority Default message priority X X X X X
DistLists Distribution list support X X
HardenGetBackout Whether to maintain an accurate backout count X X
InhibitGet Controls whether get operations for the queue are allowed X X X
InhibitPut Controls whether put operations for the queue are allowed X X X X X
InitiationQName Name of initiation queue X X
MaxMsgLength Maximum message length in bytes X X
MaxQDepth Maximum queue depth X X
MediaLog Identity of oldest log extent (or oldest journal receiver on IBM i ) needed for media recovery of a specified queue
MsgDeliverySequence Message delivery sequence X X
OpenInputCount Number of opens for input X
OpenOutputCount Number of opens for output X
ProcessName Process name X X
QDepthHighEvent Controls whether Queue Depth High events are generated X X
QDepthHighLimit High limit for queue depth X X
QDepthLowEvent Controls whether Queue Depth Low events are generated X X
QDepthLowLimit Low limit for queue depth X X
QDepthMaxEvent Controls whether Queue Full events are generated X X
QDesc Queue description X X X X X
QName Queue name X   X X X
QServiceInterval Target for queue service interval X X
QServiceIntervalEvent Controls whether Service Interval High or Service Interval OK events are generated X X
QType Queue type X X X X
RemoteQMgrName Name of remote queue manager X
RemoteQName Name of remote queue X
RetentionInterval Retention interval X X
Scope Controls whether an entry for the queue also exists in a cell directory X X X
Shareability Queue shareability X X
TriggerControl Trigger control X X
TriggerData Trigger data X X
TriggerDepth Trigger depth X X
TriggerMsgPriority Threshold message priority for triggers X X
TriggerType Trigger type X X
Usage Queue usage X X
XmitQName Transmission queue name X

Parent topic: Attributes of objects on IBM i