April 2026: Delivered the Global Timestamp Oracle (TSO) Service for apache/doris, introducing a global, monotonically increasing timestamp generator to support distributed transaction commits. The feature calibrates and maintains a time window, with a master-only TSOService daemon. Commit workflow now fetches a commit TSO during transaction commit and persists it with rowsets; per-rowset commit_tso is stored in RowsetMeta and surfaced via information_schema.rowsets (COMMIT_TSO). A REST API at /api/tso returns current TSO state, including window end time and decomposed physical/logical parts. Tables can enable TSO per CREATE/ALTER TABLE via enable_tso; default off to preserve backward compatibility. New metrics (tso_clock_drift_detected, tso_clock_updated, etc.) improve observability. Comprehensive unit and regression tests validate TSOTimestamp, TSOService behavior, commit TSO propagation, and /api/tso. Reference: commit 03290d2399acede451e461c532804969b688b340.

December 2025 monthly performance summary for GreptimeTeam/greptimedb: Delivered a unified approach to database compaction by unifying TTL options across regions and enabling dynamic fetch in a single API call. This reduces round-trips, simplifies configuration, and enhances observability; updates to unit tests and added debug logging improve traceability and maintainability. A bug fix established consistent TTL/compaction behavior across components (commit cea578244cb64833e416dda20be10b270da24800).

Monthly performance summary for 2025-11 (repository: crossoverJie/starrocks). Key feature delivered: Dynamic defaults for lag and lead window functions, enabling a column as the third argument to provide per-row default values. This enhances analytics and dashboarding flexibility by removing the need for constant defaults and allowing data-driven defaults. Commit reference: ee4af17fce3d22ce2ea0e4b99e290848aaca61b3 (PR #60209). Major bugs fixed: No major bugs reported/fixed in this period. Overall impact and accomplishments: Expanded query expressiveness and robustness in analytics workloads; reduced manual data prep for default values; improved user experience for analytic queries and dashboards; demonstrated end-to-end feature delivery from design to commit, with clear documentation in commit messages. Strengthened repository quality through targeted feature work aligned with product needs. Technologies/skills demonstrated: SQL window functions, per-row dynamic defaults, column-based argument support, code reviews, Git-based collaboration, feature delivery lifecycle, attention to backward compatibility and query planning impact.

2025-04 monthly summary for StarRocks/starrocks: Implemented SQL EXCLUDE syntax in SELECT statements to omit specified columns, significantly improving query flexibility for wide tables. The feature is tracked as #57411 and committed in 40cb5b9a3f3b27e7cc0a633fa396ca677ffc7336. Documentation has been updated across multiple languages to reflect the new functionality. No major bugs fixed this month. Overall impact: reduces data transfer and client-side filtering, enabling leaner queries and improved BI/analytics workflows. Demonstrated technologies/skills include SQL parsing/AST transformation, code quality, testing discipline, and multi-language documentation localization.

Month 2025-03: Feature-driven progress on flow observability across greptime-proto and greptimedb. Implemented cross-language FlowStat timing enhancements and richer flows metadata to improve monitoring, troubleshooting, and analytics. No major bugs fixed this period; focus on reliable, scalable design and codegen readiness.