Understanding queue high events and time since reset

I  was testing out my java program for processing PCF messages and snagged a “problem” with queue high events.

I had set max depth of the queue to 1.

I put two messages out of syncpoint, and got the following events on the SYSTEM.ADMIN.PERFM.EVENT queue.

"PCFHeader":{
  "Type" :MQCFT_EVENT
  ,"ParameterCount" :6
  ,"Command" :MQCMD_PERFM_EVENT
  ,"Control" :MQCFC_LAST
  ,"Reason" :Queue_Depth_High
  ,"MsgSeq" :1
  ,"Version" :1
  }
  ,"QMGR_Name" :QMA 
  ,"Base_Object_Name/mqca_Base_Q_Name" :CP0000 
  ,"Time_Since_Reset" :53
  ,"High_Q_Depth" :1
  ,"Msg_Enq_Count" :1
  ,"Msg_Deq_Count" :0

and

PCFHeader":{
  "Type" :MQCFT_EVENT
  ,"ParameterCount" :6
  ,"Command" :MQCMD_PERFM_EVENT
  ,"Control" :MQCFC_LAST
  ,"Reason" :Queue_Full
  ,"MsgSeq" :1
  ,"Version" :1
 }
 ,"QMGR_Name" :QMA 
 ,"Base_Object_Name/mqca_Base_Q_Name" :CP0000   
 ,"Time_Since_Reset" :0
 ,"High_Q_Depth" :1
 ,"Msg_Enq_Count" :0
 ,"Msg_Deq_Count" :0

 

I think this is telling me

  1. The Queue high event occurred 53 seconds after some other event
  2. One message was put, causing the queue high event
  3. The queue full event occurred 0 seconds after some event.  The documentation says “Time, in seconds, since the statistics were last reset”
  4. A message was put to the queue, unsuccessfully, as Enq_Count is zero.

I think the documentation is not clear.  I did not issue a reset statistics command.   The time since reset varies between 0 and over 6000 seconds.   My qmgr Stats interval was 10 seconds.

I think the time_since_reset is time since previous event or something else, so looks pretty useless.  When I issued a reset qmgr reset(Statistics) it made no difference to the time since reset.

This time value is MQIA_TIME_SINCE_RESET in the PCF.

 

I noticed that the event messages are non persistent, so make sure you process the messages before you shut down your queue manager!

6 thoughts on “Understanding queue high events and time since reset

      1. Like all IBM MQ docs you just need to know where too look:

        [Performance event statistics](https://www.ibm.com/support/knowledgecenter/en/SSFKSJ_9.1.0/com.ibm.mq.mon.doc/q036330_.htm)

        Performance event statistics are reset when any of the following changes occur:

        A performance event occurs (statistics are reset on all active queue managers).

        A queue manager stops and restarts.
        The PCF command,

        Reset Queue Statistics, is issued from an application program.

        On z/OS® only, the RESET QSTATS command is issued at the console.

        Like

  1. Event messages are not non-persistent, they are the persistence of your event queue’s DEFPSIST attribute. Although, you should process them in a timely manner none-the-less, you can choose their persistence.

    Liked by 1 person

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