Is agent wait time accounted for in the coordinator activity lifetime histogram ?

Question:

I am running DB2 with the connection concentrator active and there is a time-spent monitor element, agent_wait_time,  to account for the time spent waiting for an agent. I'd like to know if this time is included in the activity lifetime histogram?

 

Answer:

The short answer is no, agent_wait_time does not show up in the activity lifetime histogram.

The activity lifetime concept encompasses the actual time spent executing an activity, from start to end and, by definition, events that happen before execution starts, such as the compilation of the SQL statement, are not included in this measurement.

When the connection concentrator is on, agents are assigned to a connection on a per unit of work basis with the agent_wait_time measuring the time lag between requesting and getting a coordinator agent to service a unit of work. Since activities themselves are executed within the boundaries of a unit of work, this agent wait time is happening outside of the "lifetime" of any specific activity, it is actually associated with the unit of work and session itself.

If you are trying to see if the concentrator configuration of agents to applications is introducing a lag time iwhich affecting activity performance, then it is best to look at this metric at a higher level across multiple connections or the database as a whole (e.g. using the MON_GET_DATABASE table function introduced in DB2 10.5).

Hope this answers your question.

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