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Displaying posts with tag: join-optimizers (reset)
Drizzle, Optimizer, Execution Flow

The present in my RSS feed this morning was an article by Peter Zaitsev on :
http://www.mysqlperformanceblog.com/2009/09/20/guidance-for-mysql-optimizer-developers/

One of the changes made recently to Drizzle, is a redesign of our executioner. This was done by Padraig. MySQL inherited a design where the parser uses one Global Lex Structure to fill in the members of the query for later use. This structure has members in it for every form of query that can be executed. The structure is also assigned an ENUM that will be used later for determining if the query is a SELECT, INSERT, etc... via a switch/case dispatcher.

This of course creates a number of limitations in the design, especially for Drizzle …

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