Thanks for the clarification. I basically wanted to know if database systems could make use of existing distributed-memory HPC programming models, and it seems that there is a possibility, however engineering efforts might be significant.
I really have no experience with database engineering, and I am not sure if MPI and Citus will play out well.
I hope you are considering submitting a paper/poster at HPEC'19 for your current work (http://www.ieee-hpec.org/), I think that's a good venue to engage with the GraphBLAS community in person.
