Q. What is logicalSessions?

I’m constantly getting disabled right now with Log Messages that activeSessions is full of maxSessions (1 million).

In the end, we solved this by restarting MongoDB,
For cause analysis, the $listLocalSessions command determined the current status.

However, unlike other services keeping less than 100, this MongoDB had tens of thousands of localSessions as shown in the picture.

May I know the cause of this?
What is localSession?

I use MongoDB 6.0.10.
The localSessions of primary and secondary are similar.

dbmon user is mongodb exporter for prometheus user,
displayUser is dev user

I think most of those numbers were localSession which was more than 30 minutes old last time used.
But I understand that the Timeout Default value for localSession is 30 minutes, is it a bug?