March 2026 monthly summary for the Velox project (facebookincubator/velox): Delivered a major performance optimization for the FlatNoNulls expression evaluation fast path by removing the batch size limit, and introduced a workload-driven configuration to enable or disable the optimization. This change unlocks higher throughput on common workloads and provides flexibility to disable the optimization when needed.

January 2026 delivered targeted improvements across two major repositories (apache/incubator-gluten and facebookincubator/velox) to strengthen memory management in Spark workloads and enhance JSON parsing robustness. Key work included a fix to ensure dynamicOffHeapSizingEnabled is applied on executors, and an enhancement to Spark's get_json_object in Velox with escape-sequence validation and expanded test coverage. These changes reduce runtime failures, improve stability for large-scale data processing, and demonstrate strong cross-repo collaboration and testing discipline.

2025-12 Monthly Summary: Focused on enhancing scalability and reliability for large-scale data processing. Key features delivered include enabling a new integer division function (div) in gluten with input validation and division-by-zero handling, supported by tests. Major bugs fixed include correcting an integer overflow in PrefixSort memory estimation in velox by changing maxRequiredBytes() return type from uint32_t to uint64_t, preventing underestimation and potential OOM on large datasets. Overall impact: safer, more scalable data processing pipelines with reduced risk of spills/OOM, enabling workloads beyond prior limits. Technologies/skills demonstrated: C++ memory management and type-safety improvements, testing, code reviews, and cross-repo collaboration across gluten and velox.

2025-11 Monthly Summary focusing on stability, performance, and feature parity across the Gluten and Velox stacks. Delivered memory-management refactor for Velox ShuffleWriter to improve robustness of columnar shuffles; fixed a 13-bit pageNumber overflow in VeloxSortShuffleWriter to prevent runtime instability; enhanced test coverage for cardinality errors in GlutenDeltaBasedMergeIntoTableSuite, aligning with Spark-4.0 expectations; added Spark IntegralDivide support for integral and decimal types with ANSI mode, broadening arithmetic compatibility in Spark pipelines. These changes reduce runtime failures, improve data throughput, and strengthen cross-repo reliability, enabling more predictable Spark workloads and easier maintenance.

October 2025 performance summary focusing on reliability and performance improvements in Velox and Gluten, with a strong emphasis on robust error handling, macro-level efficiency, and data-path optimization. Delivered concrete changes with visible business value: more stable error reporting, reduced runtime overhead in hot paths, and lower memory copying during columnar-to-row conversions. Also added regression coverage to prevent known crash scenarios and improved overall system reliability for production workloads.

September 2025 performance overview for IBM/velox and apache/incubator-gluten focusing on DST-aware time handling and Spark integration reliability; implemented DST-aware conversions, cleaned Spark dayofyear alias, and aligned decimal offload with Spark precision config.

August 2025 performance summary for Velox and Gluten Focused on delivering key features for nested data handling, strengthening plan validation, and correcting data correctness in Parquet-based reads. The work delivered improves analytics expressiveness, data reliability, and cross-repo collaboration with measurable business value.

Concise monthly summary for 2025-07 focusing on key accomplishments, business value, and technical achievements across IBM/velox and apache/incubator-gluten.

June 2025 performance summary focusing on stability, correctness, and throughput improvements across Velox and Gluten. Delivered critical data-parsing fixes, a new data-decoding utility, performance optimizations, and enhanced offload diagnostics. These changes improve reliability of data ingestion and Spark workloads, enable more robust handling of edge cases, and provide clearer visibility into offload decisions.

May 2025 summary focusing on stability and reliability improvements in the ObjectStore creation path for the gluten project.

April 2025 performance summary for IBM/velox: Delivered key Spark integration features, broadened type support, performance improvements, and correctness fixes. Business value: more robust Spark workloads, reduced overhead, and clearer test/docs coverage.

March 2025 delivered significant Spark SQL compatibility and numeric accuracy improvements across Velox and Gluten, expanding functionality, stabilizing edge cases, and enabling safer data ingestion. Key work included introducing new array-related functions and robust handling in Spark integration, adding a sign function in the compatibility layer, aligning decimal casting semantics with Spark/Presto, and enabling from_json in the Velox backend with comprehensive validation tests. These changes enhance business value by enabling richer analytical queries, improving correctness for numeric operations, and widening data ingestion capabilities while maintaining stability through explicit option validation.

February 2025 monthly summary focusing on key accomplishments, business impact, and technical milestones across gluten and velox repositories. Highlights include new backend function support, hash-join reliability improvements, enhanced JSON parsing, decimal arithmetic coverage, and stronger benchmark stability.

January 2025 monthly summary for IBM/velox focusing on delivering storage integration, SQL function enhancements, and join robustness. Key outcomes include adding ADLS Gen2 via ABFS sink support, expanding Spark SQL function surface with safer semantics and broader numeric support, and hardening hash join behavior for left semi joins with filters. These efforts reduce data ingestion friction, improve query correctness under ANSI off mode, and increase overall system reliability for production workloads.

Month: 2024-12 — IBM/velox delivered two high-value features that enhance security, deployment flexibility, and performance for large-scale data processing. The ABFS connector now supports SAS and OAuth authentication, the AbfsConfig has been extended to parse and handle authentication types (SharedKey, OAuth, SAS), the build now depends on azure-identity, and tests were added for the new configurations. Prefix Sorting has been enhanced with a dynamic string length configuration (prefixsort_max_string_length) and improved null-byte handling to omit the null byte for columns without nulls, reducing memory usage and improving sort performance. No major bugs were reported this month; emphasis was on feature delivery, test coverage, and performance improvements. Overall impact: expanded Azure authentication options, improved data-processing performance and memory efficiency, and strengthened maintainability through testing. Technologies/skills demonstrated: ABFS connector enhancements, Azure identity integration, configuration parsing, dynamic configuration, and memory/perf optimization.

Month: 2024-11 | IBM/velox Concise monthly summary focusing on reliability, performance, and cloud capability improvements: Key features delivered: - Decimal support for unary minus in Spark SQL: extended to decimal types (short and long decimals); documentation and comprehensive tests added. Commit: f34035b0337c25a25a61561e39cfec872404f293. (#11454) - HashJoin performance optimization: batch-wise accumulation of filtered rows to reduce sparse vectors and data copies by combining low-selectivity vectors from the join filter; improved throughput. Commit: 935d30ee1db44bddc380022abfcc02bf10f48f32. (#10987) - Azure ABFS authentication support: adds azure-identity-cpp dependency and updates shell scripts/configs to enable authentication with Azure storage services. Commit: f33b40da09441d542f32ee9ed9fb2e340d3c2a75. (#11633) Major bugs fixed: - Prefix sort layout max normalized key size safeguard: refactors to ensure the prefix length does not exceed the configured maximum, preventing inclusion of a column when total encoded size would exceed the limit; added tests for multi-key scenarios. Commit: d4bdc3b0e44bb896cc05c447b743f7f539ac2d8d. (#11496) Overall impact and accomplishments: - Improved correctness and stability for key size handling, reducing risk of incorrect query plans and data truncation. - Enhanced Spark SQL capabilities with decimal support for unary minus, expanding analytical coverage and correctness for decimal data. - Achieved measurable performance gains in join workloads through batch-wise filtering, reducing memory copies and vector sparsity. - Enabled cloud storage authentication with Azure ABFS, broadening deployment options and security posture. Technologies/skills demonstrated: - Refactoring and test-driven development to enforce key-size constraints. - SQL dialect extension and comprehensive validation for decimal inputs. - Hash join performance engineering and vectorized processing optimizations. - Dependency management and cloud authentication integration with Azure ABFS. Business value: - Safer encoding limits reduce runtime risk and troubleshooting; decimal support removes edge-case gaps in Spark-based analytics; performance improvements scale hash-join-heavy workloads; Azure ABFS support enables secure, cloud-based data lake usage.