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farhad-celo

PROFILE

Farhad-celo

Worked on the StarRocks/starrocks repository over five months, focusing on SQL engine performance and correctness. Delivered features such as dictification optimizations for UNION ALL queries, struct data types, and ARRAY_AGG low-cardinality aggregation, using C++, Java, and SQL. Enhanced query execution by improving constant tracking, memory efficiency, and optimizer support for string functions and CTEs. Addressed bugs in dictification for aggregates, UNNEST operations, and CTE-based projections, ensuring accurate data processing and reliable SQL generation. Emphasized maintainability and scalability through collaborative code reviews, targeted testing, and system configuration, contributing to more efficient analytics and robust backend development workflows.

Overall Statistics

Feature vs Bugs

67%Features

Repository Contributions

13Total
Bugs
3
Commits
13
Features
6
Lines of code
5,969
Activity Months5

Work History

May 2026

1 Commits

May 1, 2026

2026-05 monthly summary for StarRocks/starrocks: Fixed a dictification bug in CTE-based projections, improving correctness of generated SQL and stability of CTEProduce projections. This work reduces risk of incorrect results and simplifies maintenance of the projection logic across the repository.

April 2026

6 Commits • 2 Features

Apr 1, 2026

April 2026 performance summary for StarRocks/starrocks: Delivered targeted SQL optimizer enhancements and correctness fixes that improve performance on low-cardinality data, accelerate dictification workflows, and strengthen type handling for UNNEST operations. Key outcomes include expanded low-cardinality string function support, cross-component dictification propagation across physical filters and CTEs, and fixes to dictification in aggregates and UNNEST-defined types. Updated tests accompany these changes, increasing reliability for complex query plans and global dictionary usage. Skills demonstrated include SQL optimizer design, dictification techniques, CTE/physical plan integration, and test-driven validation, delivering measurable business value through faster, more correct analytics.

March 2026

2 Commits • 1 Features

Mar 1, 2026

March 2026 monthly summary for StarRocks/starrocks: Focused on performance improvements for union operations and memory efficiency. Delivered enhancements to UnionDictManager constant tracking and introduced a degree-of-parallelism aware configuration to cap local exchange buffer memory, enabling more scalable and predictable execution of union-heavy queries.

February 2026

1 Commits • 1 Features

Feb 1, 2026

February 2026 monthly summary for StarRocks/starrocks: Delivered ARRAY_AGG Low-Cardinality Optimization (Dictification) to optimize aggregations by introducing dictification for low-cardinality inputs, improving performance and memory efficiency. The change was implemented as an enhancement (referenced as #68842) and committed by Farhad Shahmohammadi. Focused on performance and scalability with minimal API impact, and validated through targeted testing to ensure backward compatibility.

January 2026

3 Commits • 2 Features

Jan 1, 2026

January 2026 performance-focused monthly summary for pinterest/starrocks. Focused on delivering performance-oriented dictification enhancements to expand optimization coverage, with contributions to UNION ALL queries and struct data types. No explicit bug fixes were reported in this month; primary work targeted efficiency, scalability, and maintainability.

Activity

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Quality Metrics

Correctness86.2%
Maintainability80.0%
Architecture81.6%
Performance81.6%
AI Usage40.0%

Skills & Technologies

Programming Languages

C++JavaSQL

Technical Skills

C++ developmentData OptimizationData ProcessingData StructuresDatabase ManagementJavaJava DevelopmentJava developmentJava programmingSQLSQL OptimizationSQL optimizationTestingUnit TestingUnit testing

Repositories Contributed To

2 repos

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

StarRocks/starrocks

Feb 2026 May 2026
4 Months active

Languages Used

JavaC++SQL

Technical Skills

SQLback end developmentdata optimizationC++ developmentJavaUnit Testing

pinterest/starrocks

Jan 2026 Jan 2026
1 Month active

Languages Used

Java

Technical Skills

Data OptimizationData ProcessingData StructuresDatabase ManagementJavaJava Development