exemgr slow down - concurrent queries then a another table query runs

Customer reported:

I found a weird behavior of exemgr. Again, we have about 10 to 20 concurrent queries running on the same table the same query structure. The exemgr cpu usage is steady , but then when another unrelated query on a different schema is submitted, the exemgr seems to stop all activities until this query is done then the cpu usage goes back up.

I'll just attach the screenshot of the monitoring has i dont have much more on this. On the screen shot the 2 down moment on the cpu are when the other query is running , the 10 concurrent are still active at that time.I would expect the cpu to go above the constant usage then down when the additional query is done.

Also followup comment from customer:

I see the same behavior on the pm. We have our recurrent query running 10 at a time, when they are alone, the PM usage goes up to 90%, when a different query same or different schema comes in play, the usage goes down to 20-30%.

They have provided CPU usage info in the Issue.

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Support tried to reproduce it and was getting a different issue happening. When the query they provided as the one running concurrently was run on our system, mysqld crashed. I tried on both centos 7 and ubuntu 18 with their configuration setup.

MCOL-3376 is the issue and it has the info need to setup and try to reproduce this issue.