June 2026 monthly summary: Focused on Iceberg V3 interoperability, schema evolution, and visibility improvements across Nimble, Velox, and Prestissimo. Delivered cross-repo features that enable per-column metadata, field-id-based schema handling, and efficient data routing for inserts and deletes. Enhanced query planning with per-column statistics and fixed data visibility gaps while strengthening tests to ensure forward/backward compatibility.

May 2026 performance highlights: Delivered critical Iceberg and Parquet reading improvements across Velox and Nimble, expanded format support, and strengthened correctness and test coverage. Key features included TIME_MICROS support in Velox Parquet reader, Nimble WriterOptionsAdapter for NIMBLE format, Iceberg V3 typed fields and dataSequenceNumber for HiveIcebergSplit, and PUFFIN format entry for Iceberg V3 Puffin containers. Major bug fix: Iceberg Equality-Delete Projection Bug Fix that preserves partition values for augmented columns and prevents query failures when equality-deletes reference non-projected columns. Overall impact: improved query correctness across Iceberg reads, broader format interoperability, and deeper test coverage with minimal churn. Technologies/skills demonstrated: Iceberg, Parquet, deletion vectors, Hive Iceberg integration, Velox-Arrow bridge, Nimble DWIO, cross-repo collaboration.

April 2026 monthly summary: Delivered substantive feature work and Iceberg ecosystem groundwork across presto and Velox, improving historical data querying, data-format interoperability, and Java-era readiness. Key contributions include Prism time travel syntax support, Iceberg V3 Java readiness via an Iceberg 1.10.1 upgrade, PUFFIN file format support, DWRF data-sink integration, and Velox V3 deletion vector/equality delete capabilities, establishing a solid foundation for correct, SQL-friendly analytics and cross-format data pipelines.

March 2026 — Prestodb/presto: Delivered end-to-end support for SQL:2011 MERGE WHEN MATCHED THEN DELETE. Completed the missing DELETE path in MERGE INTO, enabling conditional deletions during upserts and aligning Presto with the standard. Work spanned the full stack: grammar (mergeDelete), AST (MergeDelete node), parser/AstBuilder, visitors, formatter, planner (DELETE_OPERATION_NUMBER), analyzer (access control), and tests (parser round-trips and Iceberg integration tests). Release notes published.

January 2026 - Nimble (facebookincubator/nimble): Stability and correctness improvements focused on DeduplicatedColumnStatistics merge paths. The accounting/ statistics-driven logic now remains reliable after merges, reducing downstream inconsistencies in deduped statistics.