DPconv: Super-Polynomially Faster Join Ordering

Abstract

We revisit the join ordering problem in query optimization. The standard exact algorithm, DPccp, has a worst-case running time of O(3 n ). This is prohibitively expensive for large queries, which are not that uncommon anymore. We develop a new algorithmic framework based on subset convolution. DPconv achieves a super-polynomial speedup over DPccp, breaking the O(3 n ) time-barrier for the first time. We show that the framework instantiation for the C max cost function is up to 30x faster than DPccp for large clique queries.