1b01d23be2
Summary: Add counters to track block cache index/filter hits and misses. We currently count aggregate hits and misses, which includes index/filter/data blocks. Pull Request resolved: https://github.com/facebook/rocksdb/pull/4540 Differential Revision: D10459652 Pulled By: anand1976 fbshipit-source-id: 0c59eee7f12f5103dcb6686f0e7995babe63d425