July 30, 2014

MySQL Query Patterns, Optimized – Webinar questions followup

On Friday I gave a presentation on “MySQL Query Patterns, Optimized” for Percona MySQL Webinars.  If you missed it, you can still register to view the recording and my slides. Thanks to everyone who attended, and especially to folks who asked the great questions.  I answered as many as we had time for  during the session, but here […]

The small improvements of MySQL 5.6: Duplicate Index Detection

Here at the MySQL Performance Blog, we’ve been discussing the several new features that MySQL 5.6 brought: GTID-based replication, InnoDB Fulltext, Memcached integration, a more complete performance schema, online DDL and several other InnoDB and query optimizer improvements. However, I plan to focus on a series of posts on the small but handy improvements – […]

MySQL 5.6 vs MySQL 5.5 and the Star Schema Benchmark

So far most of the benchmarks posted about MySQL 5.6 use the sysbench OLTP workload.  I wanted to test a set of queries which, unlike sysbench, utilize joins.  I also wanted an easily reproducible set of data which is more rich than the simple sysbench table.  The Star Schema Benchmark (SSB) seems ideal for this. […]

MySQL 5.5 and MySQL 5.6 default variable values differences

As the part of analyzing surprising MySQL 5.5 vs MySQL 5.6 performance results I’ve been looking at changes to default variable values. To do that I’ve loaded the values from MySQL 5.5.30 and MySQL 5.6.10 to the different tables and ran the query:

Lets go over to see what are the most important changes […]

Review of MySQL 5.6 Defaults Changes

James Day just posted the great summary of defaults changes in MySQL 5.6 compared to MySQL 5.5 In general there are a lot of good changes and many defaults are now computed instead of hardcoded. Though some of changes are rather puzzling for me. Lets go over them: back_log = 50 + ( max_connections / […]

A case for MariaDB’s Hash Joins

MariaDB 5.3/5.5 has introduced a new join type “Hash Joins” which is an implementation of a Classic Block-based Hash Join Algorithm. In this post we will see what the Hash Join is, how it works and for what types of queries would it be the right choice. I will show the results of executing benchmarks […]

Percona Live MySQL Conference & Expo Was A Great Event

Thanks to all of our sponsors, speakers, speaker selection committee, event staff, and especially the attendees for making last week’s conference a resounding success. With over a thousand people, the event made a good comeback after last year’s event, but more importantly, the mood was strongly optimistic. I think a lot of people arrived with […]

Eventual Consistency in MySQL

We’re told that foreign key constraints are the best way to enforce logical referential integrity (RI) in SQL, preventing rows from becoming orphaned.  But then we learn that the enforcement of foreign keys incurs a significant performance overhead.1,2 MySQL allows us to set FOREIGN_KEY_CHECKS=0 to disable enforcement of RI when the overhead is too high.  But […]

Is there a performance difference between JOIN and WHERE?

I’ve heard this question a lot, but never thought to blog about the answer. “Is there a performance difference between putting the JOIN conditions in the ON clause or the WHERE clause in MySQL?” No, there’s no difference. The following queries are algebraically equivalent inside MySQL and will have the same execution plan.

Personally, […]

Announcing Percona Performance Conference 2009 on April 22 & 23

…any sessions this year; Peter, Vadim, and the rest of us at Percona submitted over a dozen session proposals, which were initially declined. As …Cabral is organizing.

That’s the back story — now on to the Percona Performance Conference! This is not “another MySQL conference.” It’s a performance…to Santa Clara.

We will not be the only ones speaking at Percona Performance Conference; other experts will join us in making presentations too. …to propose a session, please do so through the Percona Performance Conference website.

The Percona team looks forward to greeting you face to face …