Wednesday, February 28, 2018

FOSDEM: Histogram support in MySQL 8.0

The slides and video from my FOSDEM presentation on histogram support in MySQL can now be downloaded.  Check it out if you want to learn more about how you can create histograms to improve query plans in MySQL 8.0.

The presentation shows you how to create histograms over column values, 
presents the types of histograms you can create, and discusses best practices for using histograms.

Prior to MySQL 8.0, the query optimizer lacked statistics on columns that are not indexed.  With histograms the query optimizer will be able to make more accurate selectivity estimates for conditions on such columns.   With better estimates, the query optimizer can produce better query plans, especially for join queries.  Check out the presentation for a couple of examples of join queries that runs faster due to histograms!

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