MYR-3 and perhaps can be ripped at the same time.
https://github.com/facebook/mysql-5.6/commit/bcfbb3a333ae2b8043e7b13d4dd76d2347ae8938 : Add table statistics for rocksdb to information schema
https://github.com/facebook/mysql-5.6/commit/19f50b46bb51f335be769d1f2550c90d8b41b968 : Port v5.1 Extra Stats: Per-Table
https://github.com/facebook/mysql-5.6/commit/a5c7ed3d6668d53249c553b0367d14c2b4e1a3ea : Add additional RockDB perf and I/O metrics
https://github.com/facebook/mysql-5.6/commit/5954fa33aa84c26a56229a6b301c80567e695509 : Improve perf context stats collection
MyRocks updates all of these extra table statistics that reside in ha_statistics a.k.a 'stats' within a handler.
These do look useful and we should consider taking this into Percona Server 5.7, especially since this patch is pretty well defined in this commit