DPconv: Super-Polynomially Faster Join Ordering

TL;DR

This paper introduces DPconv, a novel algorithmic framework that significantly accelerates join ordering in query optimization, breaking the traditional exponential time barrier and achieving up to 30x speedups for large queries.

Contribution

The paper presents a new subset convolution-based framework, DPconv, that outperforms the standard DPccp algorithm with super-polynomial speedups for large join queries.

Findings

DPconv achieves up to 30x faster performance than DPccp.

Breaks the $O(3^n)$ time barrier for join ordering algorithms.

Demonstrates super-polynomial speedup for large clique queries.

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 instantiation of our framework for the $C_\max$ cost function is up to 30x faster than DPccp for large clique queries.