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How to find out the value of MaxChannels that an MQ queue manager is actually using at runtime

How To


Summary

How to find out the value of MaxChannels that an MQ queue manager is actually using at runtime
The short answer is to generate an FDC agains the amqrmppa process then look at the generated FDC and search for the section "Channel Status Table Header" and you will find the entry "MaxChannels" and its value.

Objective

You have a running MQ queue manager, but you do not want to restart it yet.
You look at the qm.ini configuration file for the MQ queue manager and you see an entry for MaxChannels, but you noticed that the date stamp for the qm.ini indicates that the qm.ini was changed AFTER the queue manager was started. Thus, you are not sure if the value for MaxChannels in the qm.ini is the actual value that the queue manager is using.
The runmqsc command does not indicate the value for MaxChannels.
Thus, you would like to know if there are steps/tools that can be used to find out the value for this parameter without the need to restart the queue manager.

Steps

Consult the following technote for the details on how generate an FDC for Unix or Windows:
http://www-01.ibm.com/support/docview.wss?uid=swg21474630
How to find out if a queue manager was started with a specific environment variable
The above technote shows the steps for generating an FDC on the process amqrrmfa.
However, for our current purposes we need to generate the FDC on another process:
  amqrmppa
In order for this process to be running, you need to have an active channel. If you do not have one, then you could establish a connection from a remote MQ client via a server-connection channel.
After the FDC for the amqrmppa process is generated, then search for the section:
Channel Status Table Header  
.  
Then in that section, you can see the value for MaxChannels that the queue manager is actually using (in this case is 100):  

Channel Status Table Header  
{  
  Version                  4  
  HeaderSize               456  
  ChanSeqNo                123  
  AllocatedCount           1  
  MaxChannels              100  
  MaxActiveChannels        100
+ end +

Document Location

Worldwide

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Document Information

Modified date:
22 February 2019

UID

ibm10872924