In May 2026, delivered a core enhancement to the Apache Paimon merge workflow by introducing a Sequence-Aware LookupMergeFunction for multi-level record merging. This feature enables selecting high-level records using a user-defined sequence field and a sequence comparator, ensuring the latest records are prioritized and data quality for hierarchical datasets is improved. A targeted fix also updated the LookupMergeFunction to use sequence.field for high-level record selection, addressing edge cases in complex merges (commit a84c3826b8fee6fc854a95a86299088e57c7770b, PR #7221).

February 2026 monthly summary for apache/paimon: Focused on correctness and stability in the record comparator codegen path. Implemented a fix to the cache key for record comparators to include sort order, preventing collisions between ascending and descending comparators and ensuring correct sorting across orders. Added a regression test validating comparator behavior for both sort orders. This work strengthens the reliability of paimon's sorting semantics and reduces potential customer-support incidents related to incorrect sorting.