MariaDB MaxScale and filtering plugins: how to build flexible database architectures.

MariaDB MaxScale has become a Release Candidate, for this achievement we must thank all the companies that agreed to be part of the MaxScale Beta test project and the entire MariaDB team that was involved in this study. This important step in the life of MaxScale has had a major impact on MaxScale's Quality Assurance process.

The test We decided to ask for help from several companies, to test MaxScale in "real" environments with customized settings, different configurations and with traffic load as close to reality as possible. The company Colt Engine srl, owner of the Joomlahost.it brand, is an Italian hosting company based in Turin that showed a lot of interest in this project right from the start, they were big fans of MariaDB MaxScale and were very enthusiastic about being the first testers of MaxScale starting from the beginning of 2014 when it was still in the Alpha version. In fact, they themselves suggested some filtering plugins which were then implemented.

In November, we started to develop a possible test environment together and Colt Engine decided to include MaxScale in the production of one of its projects. What I would like to show in this post is one of the possible infinite ways MaxScale can help database administrators and architects solve different problems and easily design a flexible architecture. Colt Engine is an Internet Service Provider, as well as the official Italian hosting provider for Joomla!, in my opinion one of the best testers.

Filtering plugins in Joomla! hosting , in most (if not all) cases there is no help that can indicate which applications are running on their servers and how these are accessing instances of MariaDB or MySQL (they are now using both MariaDB and MySQL, but will gradually move all servers to MariaDB). It is not easy to predict the traffic loads or the number of connections that a specific application will need over time and it is not easy to manage or distribute them.

Some Joomla! plugins that are available, use obsolete instructions, or that have been modified ("TYPE =" versus "ENGINE =" in the CREATE TABLE, to name just one of the most common). In this particular case, MaxScale can filter out all obsolete syntaxes and give Colt Engine the ability to decide which specific server with a particular MariaDB/MySQL release to direct requests to, or better yet, replace the obsolete keyword (as in the previous example) with the most up-to-date syntax and keep all servers aligned with the same database version.

It is easy to understand that if you need to monitor hundreds of servers it is important to have a reliable and scalable platform, however, when this is not possible, or during transition periods, MaxScale can give you the ability to integrate different database versions and constantly route queries to specific servers based on specific rules.

The Tee filter Another part of the test environment involves another important MaxScale filter, namely the Tee filter. This filter allows you to duplicate queries across different types of database servers, so you can create servers with different workloads with truly unique service balancing technology. In reality, the specific use of the Tee filter gave important feedback to our MaxScale engineers who, thanks to this, were happy to refine the original design of the Tee filter and allow a more advanced use of it.