The Case for Cardinality Lower Bounds — mentioned by mihailstoian

Wed, 28 Jan 2026 17:36:27 GMT

If you're referring to estimating join sizes, i.e., the stuff you have to estimate before you actually build the query plan, we're _almost_ there (but not yet). Do check out the following papers that show that you can obtain provable bounds on your join sizes. Basically, given a SQL query, they'll tell you how many tuples (max and min, respectively) the query will return. 1. LpBound: join size upper bounds. It still doesn't have full SQL coverage, e.g., string predicates, window functions, subqueries etc., but as with all cool stuff, it takes time to build it. 2. xBound: join size lower…

Paper and discussion history. A mention is not an endorsement.

The Case for Cardinality Lower Bounds · HackerPapers discussions

The Case for Cardinality Lower Bounds — mentioned by mihailstoian