When namenode becomes unresponsive by
HADOOP-4693 (large filelist calls), metrics has been helpful in finding out the cause.
When gc time hikes, "FileListed" metrics also hiked.
In 0.18, after we fixed "FileListed" metrics so that it shows number of operations instead of number of files listed (
HADOOP-3683), I stopped seeing this relationship graph.
Can we bring back "NumbverOfFilesListed" metrics?