Panel choices
The following choices are provided in the Work with MQM channels panel and the Work with Channel Status panel.
F6=Create
Use the Create option, or enter the CRTMQMCHL command from the command line, to obtain the Create Channel panel.
With this panel, you create a new channel definition from a screen of fields filled with default values supplied by WebSphere MQ for iSeries. Type the name of the channel, select the type of channel you are creating, and the communication method to be used.
When you press Enter, the panel is displayed. Type information in all the required fields in this panel, and the three pages making up the complete panel, and then save the definition by pressing Enter.
The channel name must be the same at both ends of the channel, and unique within the network. However, restrict the characters used to those that are valid for WebSphere MQ for iSeries object names.
All panels have default values supplied by WebSphere MQ for iSeries for some fields. You can customize these values, or you can change them when you are creating or copying channels. To customize the values, see the WebSphere MQ for iSeries System Administration.
You can create your own set of channel default values by setting up dummy channels with the required defaults for each channel type, and copying them each time you want to create new channel definitions.
Table 46 shows the channel attributes for each type of channel.
Table 46. Channel attribute fields per message channel type
Attribute field Sender Server Receiver Requester Batch size Yes Yes Yes Yes Channel name Yes Yes Yes Yes Channel type Yes Yes Yes Yes Connection name Yes Yes Yes Context Yes Yes Disconnect interval Yes Yes Heartbeat interval Yes Yes Yes Yes Long retry wait interval Yes Yes Long retry count Yes Yes Maximum message length Yes Yes Yes Yes Message channel agent name Yes Message exit user data Yes Yes Yes Yes Message retry exit count Yes Yes Message retry exit data Yes Yes Message retry exit interval Yes Yes Message retry exit name Yes Yes Nonpersistent message speed Yes Yes Yes Yes Receive exit Yes Yes Yes Yes Receive exit user data Yes Yes Yes Yes Security exit Yes Yes Yes Yes Security exit user data Yes Yes Yes Yes Send exit Yes Yes Yes Yes Send exit user data Yes Yes Yes Yes Sequence number wrap Yes Yes Yes Yes Short retry wait interval Yes Yes Short retry count Yes Yes Transport type Yes Yes Yes Yes Transmission queue Yes Yes Message exit Yes Yes Yes Yes
2=Change
Use the Change option, or the CHGMQMCHL command, to change an existing channel definition, except for the channel name. Simply type over the fields to be changed in the channel definition panel, and then save the updated definition by pressing Enter.
3=Copy
Use the Copy option, or the CPYMQMCHL command, to copy an existing channel. The Copy panel enables you to define the new channel name. However, restrict the characters used to those that are valid for WebSphere MQ for iSeries object names; see the WebSphere MQ for iSeries System Administration.
Press Enter on the Copy panel to display the details of current settings. You can change any of the new channel settings. Save the new channel definition by pressing Enter.
4=Delete
Use the Delete option to delete the selected channel. A panel is displayed to confirm or cancel your request.
5=Display
Use the Display option to display the current definitions for the channel. This choice displays the panel with the fields showing the current values of the parameters, and protected against user input.
8=Work with Status
The status column tells you whether the channel is active or inactive, and is displayed continuously in the Work with MQM Channels panel. Use option 8 (Work with Status) to see more status information displayed. Alternatively, this can be displayed from the command line with the WRKMQMCHST command. See Work with channel status.
- Channel name
- Communication connection name
- In-doubt status of channel (where appropriate)
- Last sequence number
- Transmission queue name (where appropriate)
- The in-doubt identifier (where appropriate)
- The last committed sequence number
- Logical unit of work identifier
13=Ping
Use the Ping option to exchange a fixed data message with the remote end. This gives some confidence to the system supervisor that the link is available and functioning.
Ping does not involve the use of transmission queues and target queues. It uses channel definitions, the related communication link, and the network setup.
It is available from sender and server channels, only. The corresponding channel is started at the far side of the link, and performs the start up parameter negotiation. Errors are notified normally.
The result of the message exchange is presented in the Ping panel for you, and is the returned message text, together with the time the message was sent, and the time the reply was received.
Ping with LU 6.2
When Ping is invoked in WebSphere MQ for iSeries, it is run with the USERID of the user requesting the function, whereas the normal way that a channel program is run is for the QMQM USERID to be taken for channel programs. The USERID flows to the receiving side and it must be valid on the receiving end for the LU 6.2 conversation to be allocated.
14=Start
The Start option is available for sender, server, and requester channels. It should not be necessary where a channel has been set up with queue manager triggering.
The Start option is also used for receiver channels that have a DISABLED or STOPPED status. Starting a receiver channel that is in DISABLED or STOPPED state resets the channel and allows it to be started from the remote channel.
When started, the sending MCA reads the channel definition file and opens the transmission queue. A channel start-up sequence is executed, which remotely starts the corresponding MCA of the receiver or server channel. When they have been started, the sender and server processes await messages arriving on the transmission queue and transmit them as they arrive.
When you use triggering, you will need to start the continuously running trigger process to monitor the initiation queue. The STRMQMCHLI command can be used for this.
At the far end of a channel, the receiving process may be started in response to a channel startup from the sending end. The method of doing this is different for LU 6.2 and TCP/IP connected channels:
- LU 6.2 connected channels do not require any explicit action at the receiving end of a channel.
- TCP connected channels require a listener process to be running continuously. This process awaits channel startup requests from the remote end of the link and starts the process defined in the channel definitions for that connection.
When the remote system is OS/400, you can use the STRMQMLSR command for this.
Use of the Start option always causes the channel to re-synchronize, where necessary.
For the start to succeed:
- Channel definitions, local and remote must exist. If there is no appropriate channel definition for a receiver or server-connection channel, a default one is created automatically if the channel is auto-defined. See Channel auto-definition exit program.
- The transmission queue must exist, be enabled for GETs, and have no other channels using it.
- MCAs, local and remote, must exist.
- The communication link must be available.
- The queue managers must be running, local and remote.
- The message channel must be inactive.
To transfer messages, remote queues and remote queue definitions must exist.
A message is returned to the panel confirming that the request to start a channel has been accepted. For confirmation that the Start process has succeeded, check the system log, or press F5 (refresh the screen).
15=End
Use the End option to request the channel to stop activity. The channel will not send any more messages until the operator starts the channel again. (For information about restarting stopped channels, see Restarting stopped channels.)
You can select the type of stop you require if you press F4 before Enter. You can choose IMMEDIATE, or CONTROLLED.
Stop immediate
Normally, this option should not be used. It terminates the channel process. The channel does not complete processing the current batch of messages, and cannot, therefore, leave the channel in doubt. In general, it is recommended that the operators use the controlled stop option.
Stop controlled
This choice requests the channel to close down in an orderly way; the current batch of messages is completed, and the syncpoint procedure is carried out with the other end of the channel.
16=Reset
The Reset option changes the message sequence number. Use it with care, and only after you have used the Resolve option to resolve any in-doubt situations. This option is available only at the sender or server channel. The first message starts the new sequence the next time the channel is started.
17=Resolve
Use the Resolve option when messages are held in-doubt by a sender or server, for example because one end of the link has terminated, and there is no prospect of it recovering. The Resolve option accepts one of two parameters: BACKOUT or COMMIT. Backout restores messages to the transmission queue, while Commit discards them.
The channel program does not try to establish a session with a partner. Instead, it determines the logical unit of work identifier (LUWID) which represents the in-doubt messages. It then issues, as requested, either:
- BACKOUT to restore the messages to the transmission queue; or
- COMMIT to delete the messages from the transmission queue.
For the resolution to succeed:
- The channel must be inactive
- The channel must be in doubt
- The channel type must be sender or server
- The channel definition, local, must exist
- The queue manager must be running, local
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