First they picked up infinidb a while back and have been working to mainline "mariadb columnstore". Now the acquisition of Clustrix and discussion of mainlining that also. It looks like MySQLs separation of the storage engines is paying off in their ability to keep one interface but allowing significantly different backends to meet the different workload requirements.

There has been a lot of work expanding the storage engine API so columnstore can be mainlined and work so spider can progress. I imagine that progress has showed them that they are likely to be able to integrate a much larger and less connected (to existing mariadb) code base like clusterix. I can only open they decide to open source (BSL license?) the clusterix solution eventually.

Between MyRocks (replacing tokudb), columnstore, spider and eventually clustrix seems that mariadb is trying to making the case that they can handle any size workload being through at it.