December 2025: DataFusion SQL parser parameter handling hardened. Implemented case sensitivity behavior for named parameters, ensured unquoted identifiers are matched case-insensitively while quoted identifiers are matched case-sensitively, and added tests to validate both paths. Changes include normalizing signature parameter names during lookup and introducing an ArgumentName struct to preserve quote semantics. The work aligns with SQL standards and improves reliability for function calls with mixed-case parameter names.

November 2025: Delivered named arguments for aggregate and window UDFs in DataFusion, enabling users to specify arguments by name, improving readability and reducing errors from argument ordering. The change is additive and non-breaking, with accompanying documentation and tests to ease adoption. PR 1ed6e5138f6e18f2325739af7f03af6fc9611e53 implements the feature and closes portions of https://github.com/apache/datafusion/issues/17379, aligning DataFusion’s UDF API with the existing named-argument approach used for scalar UDFs.

2025-10 Monthly summary: Focused on delivering a high-value feature for DataFusion: PostgreSQL-style named arguments for scalar functions, with robust argument resolution, improved diagnostics, and end-to-end test coverage. Extended signatures with parameter_names to support named arguments; feature is integrated into the physical planning phase. Comprehensive unit and integration tests validate correctness and user-facing error messages. Business impact includes improved usability, reduced miscalls, and faster development cycles for UDF authors.