Improving Unordered Distinct Efficiency in the Vectorized SQL Engine

Archer Zhang, a backend engineering intern at Cockroach Labs, has improved the algorithm behind some SQL operators in CockroachDB's vectorized execution engine to reduce memory usage and speed up query execution. Specifically, he focused on improving the unordered distinct operator by optimizing its performance and reducing its memory footprint. The new algorithms address existing inefficiencies and can provide a significant boost in speed for certain types of queries. These improvements are part of CockroachDB's 20.1 release.