Investigate mariadb support

[altmannmarcelo]

Description

Investigate what is required to suport mariadb. We have had some interest in the past and it seems to be a small lift to add support for it.

The biggest difference is that mariadb uses row events (update/delete/insert) v1, different from mysql, which uses v2.

Apart from that, GTID is also different from both.

Change in user-visible behavior

Requires documentation change

[nickchomey]

I would love support for MariaDB. And I think there's a much larger amount of people using it than commonly estimated.

DB-Engines seems to be the most "official" ranking, but their method uses things like mentions on the web, job postings, google trends etc...

However, due to their near-complete compatibility, I almost exclusively refer to mysql when I'm actually using mariadb. I have to figure most people are the same. Its like S3-compatible, Redis-compatible, etc... People just say S3/Redis. Chromium derivatives might even apply here too - when it comes to Browser APIs, you can generally just say Chrome vs Firefox vs Safari.

The latest Stack Overflow survey suggests a much higher usage rate (17% for Mariadb, 40% for mysql, 49% for postgres), and it's probably higher.

So, if it isn't too much of an effort to add support, I think it would be well worth implementing sooner than later.

[nickchomey]

There's also this existing issue asking about Mariadb support. Not sure if you want to merge them somehow.

#728