Expand description
Join graph: nodes are individual relations (a single table or a materialised CTE / subquery output), edges are equijoin predicates. The DPccp enumerator walks this graph to pick a join order.
The graph is dense by design (u64 bitmask side sets) so DP cache
lookups can use bitmasks directly. With 64 relations max this
suffices for every shape the UQA SQL compiler can build.