What is Optimizer Trace?
After reading topic about Optimizer Tracer by Morgan Tocker decided to test it.
From Optimizer Trace and EXPLAIN FORMAT=JSON in 5.7:
Optimizer trace is a new diagnostic tool introduced in MySQL 5.6 to show how the optimizer is working internally. It is similar to EXPLAIN, with a few notable differences:
It doesn’t just show the intended execution plan, it shows the
You enable the optimizer trace, then you …