How to Reduce Impact of 'imsimta qm sum -data -oldest' on Job_Controller ? (Doc ID 2454582.1)

Last updated on MAY 07, 2021

Applies to:

Goal

Received an alert email from msprobe:

It appears the above is due to a combination of two things:

• Started doing "imsimta qm sum -data -oldest" every minute so the age of messages in the queue could be monitored
• Started using filter_discard = 2 and system has accumulated over 20,000 messages in the filter discard channel

Wondering if '-data' (without '-oldest') makes a request which job_controller can answer from a summary data structure, but '-oldest' causes it to walk its entire in-memory queue structure to examine the dates. Is that correct ?

Why this is needed ?

We need to do "imsimta qm sum -data -oldest" because we need more fine-grain monitoring of our queues.  Historically, we have only alerted when the sum of all the queues reaches a certain level.  That can lead to false alarms. A large number of messages could be no problem at all if they are all relatively recent.  A small number of messages could indicate a serious problem if they are all relatively old.  Doing "imsimta qm sum -oldest" (without -data) might be a workaround, but that will create a significant IO load. So this is not a valid workaround.

How bad is the impact ?

The impact of "imsimta qm sum -data -oldest" taking several seconds and using a lot of CPU is not really too bad. Who cares if it uses a little CPU or takes a few seconds to get gather the required data ? However, if msprobe detects that job_controller is not responding during this, then doesn't that mean that processes doing enqueues are also having trouble communicating with job_controller? If that is the case, then the impact of this could be that messages get dropped into the queue without job_controller being notified. That would mean that our attempts to monitor the queue could be causing messages to sit in the queue for possibly a few hours before being tried for the first time. That could be a very significant problem if it happens to an important message or if it impacts customer communications.

Solution

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