This talk gives an exhaustive coverage of subquery optimizations in MySQL. The introduction part describes subquery optimizations in MySQL 4.1/5.0. The main part covers new subquery optimizations in MySQL 6.0:
The description of each of the optimizations is accompanied by a demonstration of how the optimization speeds up execution of a real-world query and how it is reflected in the EXPLAIN output.
The talk ends with a description of our plans for future subquery
Sergey Petrunia is a member of MySQL Query Optimizer team. He has implemented query optimizer features like index_merge access, partition pruning, semi-join subquery optimizations, and numerous smaller improvements.
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