Comment by Shivetya

I am quite sure other implementations of SQL have similar tools but from my support of an iSeries.

The SQL scripting function is a tool run from a desktop, all emulation and such is JAVA based, with the feature to ask the system what the query is doing. The feature called Visual Explain will explode the query into a graphic representation of how the system optimized it to run. It will recommend indexes as needed. This is very good for understanding when table scans are forced, how files actually joined up, and more.