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Xingyuan Lin

PROFILE

Xingyuan Lin

Over six months, contributed to StarRocks/starrocks and crossoverJie/starrocks by building features that enhanced query profiling, pipeline reliability, and SQL analysis. Developed UI enhancements for query profile inspection, added materialization hints for CTEs, and introduced configurable logging thresholds to optimize performance and resource usage. Addressed a critical in-place mutation bug in the query planner, improving aggregation correctness. Enhanced profiling by integrating EXPLAIN COSTS with desensitized output for privacy. Strengthened streaming pipeline state management with defensive checks and robust sink notifications. Work spanned C++, Java, and SQL, demonstrating depth in backend development, pipeline management, and debugging complex distributed systems.

Overall Statistics

Feature vs Bugs

86%Features

Repository Contributions

8Total
Bugs
1
Commits
8
Features
6
Lines of code
920
Activity Months6

Work History

June 2026

2 Commits • 1 Features

Jun 1, 2026

In June 2026, focus was on strengthening streaming pipeline reliability and data integrity in the crossoverJie/starrocks repo. Delivered robust pipeline completion handling and sink notification enhancements, ensuring downstream sinks are reliably notified when the distinct aggregate source operator finishes, and reinforced state management with defensive checks in the pipeline driver.

May 2026

1 Commits • 1 Features

May 1, 2026

May 2026 (2026-05) performance and profiling uplift for StarRocks/starrocks. Key feature delivered: Query Profiling Enhancements to include EXPLAIN COSTS in query profiles, controlled by a new session variable, with output desensitized to protect sensitive SQL content. This improves debugging visibility and cost-aware optimization while maintaining data privacy. No major bugs fixed this month. Impact: clearer cost visibility across queries, safer profiling, and easier adoption for performance tuning. Technologies/skills demonstrated include feature flag design via session variable, profiling instrumentation, output desensitization, and commit-level traceability.

April 2026

1 Commits

Apr 1, 2026

Month: 2026-04 — Monthly summary for StarRocks/starrocks dev work focusing on correctness and stability of pushdown optimization. Key achievement: fixed a in-place mutation bug in PushDownAggregateRewriter that caused incorrect aggregation results when multiple aggregations referenced the same column. The fix ensures shared CaseWhenOperator and CallOperator instances are not mutated in place, preserving isolation across aggregations and preventing cross-query corruption. Impact: eliminates a class of incorrect results in complex aggregate queries, improving reliability of query execution paths that rely on pushdown aggregation. The change reduces data correctness risk and enhances stability for analytics workloads. Process and collaboration: committed the fix to StarRocks/starrocks (commit f90720c96e2e2cc6cc72416a8ad189984e33976b) and progressed through code review and validation to prevent regressions. Technologies/skills demonstrated: C++ code corrections in the query planner/execution path, debugging shared-object mutation, patch verification, and collaborative code review.

March 2026

1 Commits • 1 Features

Mar 1, 2026

March 2026 monthly summary for StarRocks/starrocks development focused on improving query optimization and correctness through materialization hints in CTEs. This period delivered a targeted feature with validation for recursive CTEs and SQL generation updates to honor materialization status, enabling more efficient query planning and potential runtime performance gains.

February 2026

2 Commits • 2 Features

Feb 1, 2026

February 2026 monthly performance summary focusing on performance optimizations in profiling workflows and log management across cross-repo work. Focus remained on business value, stability, and scalable telemetry. Deliverables contributed to reduced profiling overhead and improved log/resource efficiency, enabling better resource utilization and lower storage costs.

October 2025

1 Commits • 1 Features

Oct 1, 2025

Month: 2025-10. Focused on delivering a key performance engineering feature in StarRocks/starrocks: a Query Profile Analysis UI Enhancements that enables analysts to inspect query profiles, view and format SQL, and configure the display length. This work strengthens debugging workflows and accelerates performance investigations.

Activity

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Quality Metrics

Correctness93.8%
Maintainability85.0%
Architecture87.6%
Performance85.0%
AI Usage25.0%

Skills & Technologies

Programming Languages

C++JavaMarkdown

Technical Skills

Backend DevelopmentC++JavaPipeline ManagementSQLSQL FormattingSoftware DevelopmentUI Developmentback end developmentbackend developmentconfiguration managementlogging

Repositories Contributed To

2 repos

Overview of all repositories you've contributed to across your timeline

StarRocks/starrocks

Oct 2025 May 2026
5 Months active

Languages Used

JavaMarkdown

Technical Skills

Backend DevelopmentSQL FormattingUI DevelopmentJavabackend developmentconfiguration management

crossoverJie/starrocks

Feb 2026 Jun 2026
2 Months active

Languages Used

C++

Technical Skills

C++backend developmentPipeline ManagementSoftware Development