A bunch of (hopefully) self-explanatory slides about new subquery optimizations in MySQL 6.0 is available here (UPDATE: here’s a working link). The slides are from this MySQL University session, so there was an audio stream but there were some difficulties with it and it is not available now.
- Priority queue optimization for filesort is now visible in MariaDB 10.0
- New feature in MariaDB 10.1: ANALYZE statement
- Optimizations for derived tables in MySQL 5.6 and MariaDB 5.5+
- Engineering behind EXPLAIN FORMAT=JSON (or lack thereof)
- An interesting case in ORDER BY LIMIT optimization
- Comparing query optimizer features in MariaDB 10.0 and MySQL 5.6