Summer 2023: Fuzzing Vitess at PlanetScale

This post details the development of a random query fuzzer for Vitess's planner. The fuzzer randomly selects tables and columns to generate queries with clauses like SELECT, GROUP BY, WHERE, and ORDER BY. It also includes enhancements for random expression generation and query simplification, comparing results against MySQL to identify discrepancies. The work contributes to improving the robustness and correctness of Vitess releases by identifying and fixing bugs in the query planner.