The following metrics would be very useful to have for tracking and debugging broker issues in AMQ Online:

• number of blocked producers due to error condition (error condition as a label)
• histogram of producer latencies
  • end 2 end time from receiving message on broker and storing on disk
  • for writing messages to journal
  • for writing message to page store
• number of consumers without credits
• number of failed deliveries (rejected, modified, released)
• histogram of consumer latencies
  • for reading message from disk
  • end 2 end time for reading message from disk until consumer acknowledgement was received
  • time from message was sent until acknowledgement was received