v.23.12Improvement

Fix and Enhance Query Transformation for External Databases

Fix and improve transforming queries for external databases, to recursively obtain all compatible predicates. #57888 (flynn).
Fixes and improves the transformation of queries for external databases by recursively extracting all compatible predicates.

Why it matters

This feature addresses issues with query transformations when ClickHouse interacts with external databases, ensuring that all compatible predicates are recursively obtained. This enhances the accuracy and efficiency of predicate pushdown, leading to better query performance and correctness when querying external data sources.

How to use it

The improvements are applied internally when ClickHouse generates queries for external databases. Users benefit automatically from enhanced predicate extraction without any additional configuration.