There are so many exciting new features in MySQL 5.6 that I almost don't know where to start. To mention a few, MySQL's
multi-core scalability has been significantly improved to meet modern hardware, InnoDB has better
index statistics, much
better performance, and
online ALTER, replication has
multi-threaded slaves and
global transaction identifiers,
performance schema has added capabilities to provide a much more detailed view of what's bogging a server down, and more... much more.
However, my prime interest is the optimizer, which is why I've compiled a list of my favorite new optimizer features in 5.6. Here goes:
New ways to understand query plans:
The most common requests from DBAs is to get more information to understand how and why MySQL behaves like it does. You can come a very long way at squeezing performance out of MySQL if you can answer questions like "What Query Execution Plan (QEP) did the server decide to use?" and "Why was this QEP picked?". In this department, MySQL 5.6 delivers a bunch of new features.