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Overview of fragmented MySQL InnoDB tables

The major engine for MySQL is InnoDB, it complies with the ACID properties for a transactional database engine. Even if InnoDB is the most recommended engine for MySQL, it has also some caveats. The biggest criticism lies in the amount of disk space used. And even when we remove data, tablespaces don’t shrink. This post is about those tables that … Read More


pre-FOSDEM MySQL Day 2018

As last year, we will take advantage of the mass presence of our engineers during FOSDEM to organize a MySQL Day once again. The Agenda is not yet known, but save the date and schedule your trip to Brussels keeping in mind that Friday February 2nd 2018, there will be a full day dedicated to MySQL ! More to come … Read More


From MySQL 5.6 partitioning to 5.7 and beyond

As you may already know,  since MySQL 5.7.17, the generic partitioning handler in the MySQL server is deprecated, and is completely removed in MySQL 8.0. So now, in MySQL 5.7, the storage engine used for a given table is expected to provide its own (“native”) partitioning handler. Currently, only the InnoDB and NDB storage engines do. MySQL 5.7 supports generic … Read More


MySQL 8.0 Data Dictionary Tables… and why they should stay protected

With MySQL 8.0, one key feature is the new Data Dictionary. The system tables that were previously in MyISAM are now replaced by new protected ones in the DD. My friend Giuseppe already explained how you could see those tables using sandbox  and he also warned you that you should not mess up with them in this post too. I’ll … Read More


Where does my MySQL configuration variable value come from ?

As you may already know, there are many different places where a MySQL configuration variables can be initialized. In MySQL 8.0, we added in performance_schema a table allowing you to easily find where a variable was defined. Let’s check this in action with max_connections for example. I started mysqld and now I check the value of max_connections: mysql> show global … Read More


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