Why MariaDB 10.2 uses again InnoDB instead of Percona XtraDB?

Question

MariaDB homepage says that they use Percona XtraDB until 10.1 and from 10.2 on they are going to use normal InnoDB again (https://mariadb.com/kb/en/mariadb/xtradb-and-innodb/).

This does not seem reasonable to me, because XtraDB seems to be the better / improved version of InnoDB (https://www.percona.com/software/mysql-database/percona-server/feature-comparison). So is this a typo, are there any legal issues, or is the new version of InnoDB simply better than XtraDB?

There is even a question on MariaDB page, but it has not been answered for weeks now.

Sry, could not append all related links because of Stackoverflow rules.

Answer 1

As far as I have seen, they did it for better compatibility from mysql. During my training at M17 they did not say anything about it. I had discovered this during that last 10 minutes of the social hour as I was providing feedback.

I'm sure its because its not GA yet.

Answer 2

Keeping InnoDB (or XtraDB) up to date with MySQL (Percona) is a complex task. It took us more than half a year to migrate from InnoDB-5.6 to InnoDB-5.7 in 10.2. Doing it again for XtraDB would probably have required only slightly less than this. For us to embark on such project, it must bring significant benefits to our users.

XtraDB had many great improvements over InnoDB in 5.1 and 5.5. But over time, MySQL has implemented almost all of them. InnoDB has caught up and XtraDB is only marginally better. Not enough to justify a multi-month merge that would delay 10.2-GA for everyone.

In particular, the only real improvement that XtraDB 5.7 seems to have is for a write-intensive I/O-bound workload, where innodb_thread_concurrency control is disabled.

With a proper innodb_thread_concurrency, XtraDB is only marginally better. We didn't want to delay 10.2-GA by up to half a year for the sake of those few users who have write-intensive I/O-bound InnoDB workload and don't know how to configure innodb_thread_concurrency.

Note, we still consider incorporating XtraDB optimizations, but as patches, rather than XtraDB as a whole, which no longer has numerous all-over-the-code improvements.

https://mariadb.com/kb/en/library/why-does-mariadb-102-use-innodb-instead-of-xtradb/