When database queries are slow a good approach is to use EXPLAIN to get the execution plan of the queries. But the result is not always obvious. In this post I show you how I use EXPLAIN to solve a real performance issue.

Today I tell you a little story about MariaDB and Doctrine2 sinking and how Redis, coming to save them, sinks them even faster. Feedback on my setbacks with Redis and Doctrine2 hoping to relieve a MariaDB out of breath.

Alter table operation can be a very long task, depending on your database. It's often that database administrator wait too run these operations and do it late in the night to avoid disturbing user. But solutions exist to allow alter table without locking table, pt-online-schema-change from Percona Toolkit is one of these solutions.