Comment 2 for bug 1594947

This not seems like a bug.

Long period statistics could be a very long operation in database and depends on amount of data that was stored during required period of time. MongoDB will operate with timestamp index because data should be sorted in write order and this factor make MongoDB choose timestamp index as priority one. That means that all other filter parameter will be used in search request while scanning all data stored between start and end timestamps in statistics request.
So if we have a lot of data in database such find process will be rather long and as result timeout error.