April 2026 (2026-04) – lancedb/lance: Delivered a critical correctness fix for Merge Insert when handling NULL key columns, significantly improving data integrity and reliability for upsert-like workflows. Implemented a sentinel-based approach to robustly detect source rows during outer joins, preventing silent drops of rows with NULL keys and ensuring correct Insert behavior across all ON-column scenarios. The sentinel is non-persistent (not written to disk) and is stripped before write, with propagation through DataFusion projection pushdown to avoid downstream impact. Key impact: eliminating data loss in merge flows involving NULL keys, reducing the risk to business-critical analytics and ETL pipelines that rely on correct upsert semantics. Commits reference: 46650e6f47a37977940e25062f239df1f41d2e16. Co-authored-by notes reflect collaboration across the write and planning modules to ensure end-to-end correctness.

March 2026: Two major features delivered in lancedb/lancedb, delivering business value through API flexibility, safer query construction, and cross-language parity.