MongoDB monitoring shows "currentOp()" as top query, which is from AppD?

[carl.sjoquist]

This query, "currentOp()" consistently shows as top query in the MongoDB AppD "query" and "reports".   This makes sense, of course, but it shows as being a very high percentage (50-70%) in the "weight" column, so concerned that this adds significant load.   How can we determine how much overhead/load it *really* is adding...?       

We have a separate app (Solarwinds) that indicated the master node running at 100% CPU for an extended period, so we want to be able to exclude or "explain away" the influence of this AppD query load to better understand what the root cause is.

[Anka.Thanneeru]

Hi,

Though we do not have any reference of DBAgent overhead , but it could be very minimal in terms of either cpu or memory.

Weight %, The percentage of the total time consumed by the query for the selected time duration.

The reason for currentOp() command showing top because it will be executed by the agent at every minute to get the current statistics for the running queries. It could be the case that there is not much activity on the mongo caused in showing it as top query.

So, as far as I know there should not be much impact on the database for execution of this query by the agent. 

You can further drill down down to the queries windows sections to see the complete details about the query execution.

https://docs.appdynamics.com/display/PRO44/Database+Query+Details+Window

Please do let us know if there are any further clarifications required.

Regards,

Anka