March 2026 monthly summary for spiceai/datafusion: Delivered Parquet NDV-based cardinality estimation to improve query optimization. Extracts distinct_count from Parquet metadata to inform the cost-based optimizer, supporting both single-row-group and multi-row-group Parquet files. Implemented conservative NDV propagation (max NDV as lower bound when multiple groups) and preserved NDV in projections. Added comprehensive test coverage (7 unit tests plus an integration test) validating end-to-end NDV handling and integration with Parquet metadata. This work enhances join/aggregation planning in both single-node and distributed contexts, delivering faster, more efficient query execution without breaking existing APIs. Demonstrates strong Rust/Parquet metadata handling, test-driven development, and data fusion architecture skills.

January 2026 monthly summary for substrait-io/substrait-java: Delivered a targeted enhancement to the DECIMAL type handling in the Substrait type system. Defined maximum precision and scale for DECIMAL and added tests to verify correctness, improving data accuracy for financial and analytical workloads and reducing downstream errors in serialization/deserialization of decimal values. No major bugs reported this month; the focus was on delivering a precise, tested improvement that strengthens API reliability and interoperability.

February 2025 (2025-02) monthly summary for OpenLineage/OpenLineage: Delivered feature to enhance path extraction for ArrayBuffer data in ParallelCollectionRDDs, with test coverage to validate ArrayBuffer handling. Strengthened RddPathUtils extraction logic to improve reliability of lineage data for Spark workloads. This work tightens data lineage accuracy and reduces need for manual data wrangling in downstream analytics.