WoltLab has written a software that queries a database server with a standardized language: The Structured Query Language, SQL
Well, OK, but so has... phpBB, MyBB, vBulletin, IP.Board, XenForo, WordPress... ect....
Furthermore they are setting a MySQL option which is defined in its API and using MySQLs feature of prepared statements through PDO.
Alright so they use the API. There are 3 common API's to get your php software to speak to SQL. They happen to use PDO as opposed to mysqli or mysqlnd.
Using an API isn't new.... phpBB, MyBB, vBulletin, IP.Board, XenForo, WordPress... ect.... All use an API.
Now there is a query which conforms to the SQL standard and is sent to a MariaDB server but instead of answering with a result the server crashes. Who’s fault is it?
That particularly query (or line of code). Because I can send a bunch of queries using different forum software and nothing crashes.