MyRocks in MariaDB 10.2.6

MariaDB 10.2.6 is GA. It includes MyRocks, which isn't GA yet but is much easier to use thanks to the hard work of the MariaDB team. This is a big deal if you want performant efficiency or efficient performance. For some workloads it provides better performance than InnoDB. For most (approximately all) workloads it uses much less space and writes much more efficiently. We continue to make RocksDB and MyRocks better and there are many interesting projects in progress. It runs in production, so Domas has begun finding even more things to improve. My contribution is performance evaluation and while I have been busy running tests I have fallen behind on sharing the results. I will do better over the next few months.