ChunkManager objects are kept around as long as there is a query using them. If there are a lot of long-running queries and also a lot of chunk moves/splits/merges, this can lead to a build-up of ChunkManager objects in-memory which is unbounded. We should either optimize this somehow or put a cap on the memory used by the ChunkManager, or at the very least figure out how to issue a warning that there are a lot of ChunkManager objects.

As a side note it could also be good to at least include the number of open metadata snapshots/ChunkManager objects in FTDC data since this has been a problem on several occasions.