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Channels
Use the Channels queue manager properties page from the WebSphere MQ Explorer, or the CHANNELS stanza in the qm.ini file, to specify information about channels.
- MaxChannels=100|number
- The maximum number of channels allowed. The default is 100.
- MaxActiveChannels=MaxChannels_value
- The maximum number of channels allowed to be active at any time. The default is the value specified on the MaxChannels attribute.
- MaxInitiators=3|number
- The maximum number of initiators. The default and maximum value is 3. Any value greater than 3 will be taken as 3.
- MQIBindType=FASTPATH|SHARED
- The binding for applications:
- FASTPATH
- Channels connect using MQCONNX FASTPATH; there is no agent process.
- SHARED
- Channels connect using SHARED.
- PipeLineLength=1|number
- The maximum number of concurrent threads a channel will use. The default is 1. Any value greater than 1 is treated as 2.
When you use pipelining, configure the queue managers at both ends of the channel to have a PipeLineLength greater than 1.
Pipelining is only effective for TCP/IP channels.
- AdoptNewMCA=NO|SVR|SDR|RCVR|CLUSRCVR|ALL|FASTPATH
- If WebSphere MQ receives a request to start a channel, but finds that an amqcrsta process already exists for the same channel, the existing process must be stopped before the new one can start. The AdoptNewMCA attribute allows you to control the end of an existing process and the startup of a new one for a specified channel type.
If you specify the AdoptNewMCA attribute for a given channel type, but the new channel fails to start because the channel is already running:
- The new channel tries to stop the previous one by requesting it to end.
- If the previous channel server does not respond to this request by the time the AdoptNewMCATimeout wait interval expires, the process (or the thread) for the previous channel server is ended.
- If the previous channel server has not ended after step 2, and after the AdoptNewMCATimeout wait interval expires for a second time, WebSphere MQ ends the channel with a CHANNEL IN USE error.
AdoptNewMCA is not supported on requester channels.
Specify one or more values, separated by commas or blanks, from the following list:
- NO
- The AdoptNewMCA feature is not required. This is the default.
- SVR
- Adopt server channels.
- SDR
- Adopt sender channels.
- RCVR
- Adopt receiver channels.
- CLUSRCVR
- Adopt cluster receiver channels.
- ALL
- Adopt all channel types except FASTPATH channels.
- FASTPATH
- Adopt the channel if it is a FASTPATH channel. This happens only if the appropriate channel type is also specified, for example, AdoptNewMCA=RCVR,SVR,FASTPATH.
Attention!: The AdoptNewMCA attribute might behave in an unpredictable fashion with FASTPATH channels. Exercise great caution when enabling the AdoptNewMCA attribute for FASTPATH channels.- AdoptNewMCATimeout=60|1 – 3600
- The amount of time, in seconds, that the new process waits for the old process to end. Specify a value in the range 1 – 3600. The default value is 60.
- AdoptNewMCACheck=QM|ADDRESS|NAME|ALL
- The type of checking required when enabling the AdoptNewMCA attribute. If possible, perform all three of the following checks to protect your channels from being shut down, inadvertently or maliciously. At the very least, check that the channel names match.
Specify one or more values, separated by commas or blanks, to tell the listener process to:
- QM
- Check that the queue manager names match.
- ADDRESS
- Check the communications address. For example, the TCP/IP address.
- NAME
- Check that the channel names match.
- ALL
- Check for matching queue manager names, the communications address, and for matching channel names.
AdoptNewMCACheck=NAME,ADDRESS is the default for FAP1, FAP2, and FAP3, while AdoptNewMCACheck=NAME,ADDRESS,QM is the default for FAP4 and later.
Parent topic:
Changing queue manager configuration information
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