You have a monitoring tool that alerted you that there are lots of messages in the WebSphere MQ queue SYSTEM.AUTH.DATA.QUEUE. You want to know what this system queue is used for, and whether you can clean it up to achieve the overall guideline that "a good queue is an empty queue".
You tried to remove the messages using the sample application amqsget and you got the bellow error.
$ ./amqsget SYSTEM.AUTH.DATA.QUEUE QMGR
Sample AMQSGET0 start
MQOPEN ended with reason code 2042
unable to open queue for input
Sample AMQSGET0 end
The queue SYSTEM.AUTH.DATA.QUEUE is used by Websphere MQ queue managers to store authorization data. The queue manager will manage the information stored in this queue and it should not be otherwise modified. If this queue is altered by someone or something other than the queue manager, you will break users permissions to the queue manager and its objects. This queue will increase and decrease as authority profiles are created or deleted by the command "setmqaut" and as users are granted/revoked authority to objects.
Do NOT remove the messages in the SYSTEM.AUTH.DATA.QUEUE. You can ignore the depth alert when monitoring this queue.
If you need to reduce the depth of the SYSTEM.AUTH.DATA.QUEUE, please use the command setmqaut to complete the operations. For more information about this command and authority management, please consult the related links.
Updating the OAM after changing a user's authorization
How access control is implemented by WebSphere MQ
SupportPac MS03 (saveqmgr) saving authority information
Deleting messages from SYSTEM.ADMIN.ACCOUNTING.QUEUE
WebSphere MQ WMQ