I totally hear you here :) Visibility is the most useful and always under-rated feature. If I can clarify some of the recent enhancements here: - MySQL 5.6 i

I totally hear you here :) Visibility is the most useful and always under-rated feature. If I can clarify some of the recent enhancements here: - MySQL 5.6 introduced `EXPLAIN FORMAT=JSON`. MySQL Workbench uses this to visualize query plans (important as they get complicated.) - Also in 5.6 was optimizer trace (find out why indexes were not used etc.) and performance_schema enabled by default. - MySQL 5.7 adds cost information to `EXPLAIN FORMAT=JSON` (Workbench also understands it.) - Workbench also has a set of performance views based on Performance_schema (based on a project called SYS). You can install it as standalone from here too: https://github.com/MarkLeith/mysql-sys https://github.com/MarkLeith/mysql-sys - The runtime performance data from SYS is very useful for making correct optimization decisions. Being an SQL interface is also friendly for writing your own scripts against it. Also, to clarify on your first paragraph: Yes, refactoring old code was one of the ways this was achieved. We picked refactoring targets based on performance and because some of the older code is not very testable.