The HTTP console has a section that displays:
- Last 100 write lock %
- A "write locked now" boolean
The first displays all zeros as the metric that captures is commented out.
The second was arguably useful prior to database locks but less so once document level locking is in place.
Removing these statistics will allow for reduction in the volume of statistics we gather and a lower memory footprint. Especially for mongod instances with a large # of collections, as we store stat snapshots at the collection level.