This is the issue for the initial merge of the Clustrix plugin code.
Here is the outline of the functionality:

CRUD operations are supported except for UPDATE using engine API.
Select and derived handlers are both suported.
Conditions pushdown is not supported.
Statistics isn't provided.
Bulk operations aren't supported.
To use the plugin one has to run a custom build of Clustrix that hasn't been merged in Clustrix mainline yet.