What's New in CockroachDB’s Cost-Based Query Optimizer

CockroachDB has implemented a cost-based query optimizer from scratch, which is continually being improved. In the latest release (v20.1), significant improvements have been made in various areas such as foreign key checks, limit "hints", recursive common table expressions and statement diagnostics bundle. The new implementation of foreign key checks allows for locality-sensitive index selection, while soft limits provide more accurate cost estimations by considering early execution completion. Additionally, the support for recursive CTEs has been added, making SQL a Turing-complete language. A statement diagnostics bundle has also been introduced to simplify the collection of information when reporting issues.