If you (or your customer) are paying customers (not using the Free edition) then you can use SingleStore Replicate to move data over from Oracle.
It can save quite a bit of labor. E.g. some of our sales engineers reported that what would have taken 2 weeks using dumps to CSV could be done in 2-3 days with Replicate.
Have your customer contact their account team (or team@singlestore.com) to get access to the software.