Sergei Petrunia

Optimizer Developer, Monty Program Ab

Sergei Petrunia is a query optimizer developer at Monty Program Ab. He implemented MariaDB's optimizer features like Table Elimination (MariaDB 5.1), improvements to semi-join subquery optimizations (MariaDB 5.3/5.5) and SHOW EXPLAIN (MariaDB 10.0). Prior to Monty Program, he has worked for MySQL Ab/Sun Microsystems, where he was the author of query optimizer features like Partition Pruning, Index Merge (MySQL 5.1), and numerous smaller improvements in query optimizer and other parts of the server. He maintains a highly technical blog at


It is a common knowledge that in the MySQL world you have to use indexes to optimize your queries. Indexes provide fast access to the data, indexes provide statistics. True, indexes can also be quite expensive to maintain, but what choice do we have? New MariaDB 10.0 optimizer supports storage engine independent statistics tables. Which means that you can have data statistics calculated for all... [read more]