Has there ever been any exploration to doing recursive queries (e.g.

WITH RECURSIVE ...

) to traverse tuples? I'm assuming no because you want to hydrate the application-level cache for subproblems in between, but just curious.

I think this aligns with the whole "why not a graph DB" question. Zanzibar's is designed to decompose everything as subproblems, so traversing does not fit well that model. We've discussed doing joins to spare some dispatches, e.g. when dispatch is a terminal subject

it also wouldn't work unless the arrow pointed only to another relation, as @vroldanbet said

Yeah that makes sense I think–in other words I'm assuming you would have trouble trying to model the set algebra in recursive SQL queries

sometimes yes, sometimes no