Add MariaDB compatibility tests

[hashhar]

Some duplication can be removed by adding a common base class for TestingMySqlServer and TestingMariaDBServer.

This will allow to remove the MariaDBQueryRunner but the amount of code overall ends up being similar so I left it as is.

Note that we are running the entire BaseConnectorTest against MariaDB to ensure compatibility (e.g. older versions of MariaDB had a different rename column syntax which won't be caught with the smoke tests).

[hashhar]

This change should allow us to safely upgrade our MySQL driver version without worrying about breaking compatibility unknowingly.

[findepi]

I hope that, using mariadb would fail to connect (the connector shouldn't use DriverManager to make the connection)

[hashhar]

It fails. But there isn't an explicit test added for it yet.

[findepi]

I am wondering that maybe we should add mariadb as a seaprate connector (same as mysql connector today), this would allow future compatibility, if eg we need to use different driver for MySQL and MariaDB or there are any other changes.

[findepi]

Should we run type mapping tests agains MariaDB as well, per #6910 (comment) ?

[findepi]

Let's go with current approach, i.e. without separate plugin code, except

• run type mapping tests against MariaDB as well
• add second ConnectorFactory with mariadb name
  • once done, we need to reflect this in docs somehow
• add a product test exercising the mariadb connector

[hashhar]

I'll do each of those over the coming weekend. 👍

[hashhar]

After all - MariaDB isn't very compatible with the MySQL client @findepi . 😞

There are two issues:

• MariaDB doesn't have a proper JSON type. It aliases JSON to LONGTEXT and hence the type mappings in MySqlClient for JSON don't work for MariaDB.
• MariaDB declares it's version as lower than 5.6.4 which causes MySQL driver to think that it doesn't support fractional seconds in temporal types (MySQL 5.6.4 was the first version to support them). This sadly has no solution other than using the MariaDB driver instead of MySQL driver. See https://issues.alfresco.com/jira/browse/MNT-17613 for a more detailed report.

[martint]

That’s a strong argument for having a separate connector for mariadb

[hashhar]

Superseded by #10046 which adds a dedicated MariaDB connector.