Session An Overview of the MySQL 5.0 Query Optimizer Timour Katchaounov Track: Architecture and Technology Date: Thursday, April 21 Time: 11:20am - 12:05pm Location: Magnolia TrackBack One of the main benefits of database technology is the declarative SQL interface to access data--one tells the system what is needed and the DBMS automatically discovers a way to efficiently retrieve the requested data. As with every other modern DBMS, MySQL has a component, called the "query optimizer," that performs this complex discovery task. In this talk, Katchaounov first provides some background on the main principles behind DBMS's query optimizers. He considers the general ideas behind the optimizer of MySQL and outlines several distinct phases of the query optimization process. He then takes a closer look at the implementation of the optimizer--the main data structures that represent queries and query execution plans, and the main procedures that transform them. Next he focuses on several of the most important steps of the query optimization process: the range optimizer, responsible for finding and using the right indexes for queries with range predicates, and the cost-based optimizer that finds the best way to join multiple tables. Here he details some of the new optimizer features of MySQL v. 5.0--the "greedy" optimizer that may reduce query optimization time by orders of magnitude, and new optimization of index use for OR-queries, some group-by, and distinct queries. Finally, he relates the design of new handlers to the workings of the optimizer, and concludes with the near-future plans for new optimizer features coming in the next versions of MySQL. Download presentation file

Diamond Sponsor

Platinum Sponsors

Gold Sponsors

Silver Sponsors

Media Sponsors

MySQL User Conference Sponsor Opportunities — Reach business leaders and technology influencers at the MySQL User Conference. Download Exhibitor and Sponsor Prospectus. Call Andrew Calvo at 707-829-0515 or email at

Press and Media

For media-related inquiries, contact Suzanne Axtell at

Media Center — Press releases, news, and information for the press.

Conference News