Mateusz Matan <mateuszmatan@gmail.com> writes:

We designed a custom Storage Engine (CLDB) for MySQL/MariaDB which now pass all premature tests. I wonder, how can we solve license problem... We would not share our sources, but we will just use shared library (*.so)... Which licenses should our customer who bought MariaDB with CLDB use to stay legally... If it is possible, can we use in corporation use MariaDB on GPL and just sell CLDB (storage engine) on other license (which one) ??

The central issue here is if your storage engine is considered a "derived work" of MySQL and/or MariaDB under the copyright law of your country. If it is, then you need a licence to distribute it. The GPL grants you such a licence, but only if you offer the source code to your storage engine also under the GPL licence, which you wrote you do not want to do. Therefore, if your engine is a derived work of MySQL, you need to obtain a separate licence from Oracle to distribute it. Similarly, if your engine is in addition a derived work of MariaDB (which is perhaps unlikely), you need in addition a separate licence from Monty Program for the MariaDB part. If your engine would not be considered a derived work of MySQL/MariaDB, then you do not need any licence at all. In either case, your users will be free to use your engine with MySQL/MariaDB, as the GPL grants an unrestricted licence for usage without distribution. As to whether your engine is a derived work of MySQL/MariaDB, in the end you will have to make up your own mind on this. But the usual understanding in the Open Source world is that something like a storage engine would normally be considered a derived work, especially the interface part (ha_xxx.cc). If needed, I know that separate licence is available for both MySQL and MariaDB. There was also some discussion that Oracle would offer such separate licence for free, but I do not know if this is true or any other details. - Kristian.