facebook/CacheLib
Dec 2025 – Feb 2026
3 Months active
Languages Used
C++
Technical Skills
C++Object-Oriented ProgrammingSoftware DesignC++ developmentCode RefactoringSoftware Architecture
Fenchao Du
PROFILE
Fenchao Du
Over a three-month period, Fc Du enhanced facebook/CacheLib by building robust multi-range cache management features using C++ and object-oriented design. Fc refactored the core piecewise logic to support non-contiguous range requests, extracting shared state and behavior into a new base class to enable polymorphic handling and future scalability. By centralizing common logic and cleaning up legacy code, Fc improved maintainability and prepared the codebase for migration to MultiRangeCachePieces. Fc also corrected cache hit percentage calculations for non-contiguous ranges, introducing reliable piece counting and improving telemetry accuracy. The work demonstrated depth in system design and code optimization.
Overall Statistics
Feature vs Bugs
75%Features
Repository Contributions
10Total
Bugs
1
Commits
10
Features
3
Lines of code
636
Activity Months3
Your Network
2807 peopleSame Organization
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Work History
February 2026
1 Commits
Feb 1, 2026February 2026 (2026-02) – facebook/CacheLib: Corrected cache hit percentage calculation for non-contiguous ranges and strengthened piece-counting to improve reliability and telemetry. The change fixes incorrect hit-rate computation when ranges are non-contiguous and introduces a robust counting mechanism to support MultiRangeCachePieces. Key changes include: - Implementing a virtual getNumFetchedPieces() in GenericPiecesBase to correctly count fetched pieces for both contiguous and non-contiguous range types. - Updating HTTPResponseCache hit percentage calculation to account for gaps between ranges, ensuring accurate cache metrics. - Referenced commit 97020847e68dfc44887ec146c4c208f708ede6f8 and Differential Revision D92170058. Impact: - Improves cache reliability and accuracy of performance telemetry. - Reduces risk of misinterpreting hit rates, enabling better capacity planning and faster issue diagnosis. - Demonstrates robust range-handling and maintainability in CacheLib core.
1 Commits
Feb 1, 2026February 2026 (2026-02) – facebook/CacheLib: Corrected cache hit percentage calculation for non-contiguous ranges and strengthened piece-counting to improve reliability and telemetry. The change fixes incorrect hit-rate computation when ranges are non-contiguous and introduces a robust counting mechanism to support MultiRangeCachePieces. Key changes include: - Implementing a virtual getNumFetchedPieces() in GenericPiecesBase to correctly count fetched pieces for both contiguous and non-contiguous range types. - Updating HTTPResponseCache hit percentage calculation to account for gaps between ranges, ensuring accurate cache metrics. - Referenced commit 97020847e68dfc44887ec146c4c208f708ede6f8 and Differential Revision D92170058. Impact: - Improves cache reliability and accuracy of performance telemetry. - Reduces risk of misinterpreting hit rates, enabling better capacity planning and faster issue diagnosis. - Demonstrates robust range-handling and maintainability in CacheLib core.
February 2026
January 2026
8 Commits • 2 Features
Jan 1, 2026January 2026 focused on enabling scalable, polymorphic cache management in facebook/CacheLib, aligning with MultiRangeCachePieces migration and improving maintainability. Delivered polymorphic piece range handling, centralized common logic, and migration-ready refactors, while cleaning up legacy code paths to reduce risk and prepare for broader piece iteration.
January 2026
8 Commits • 2 Features
Jan 1, 2026January 2026 focused on enabling scalable, polymorphic cache management in facebook/CacheLib, aligning with MultiRangeCachePieces migration and improving maintainability. Delivered polymorphic piece range handling, centralized common logic, and migration-ready refactors, while cleaning up legacy code paths to reduce risk and prepare for broader piece iteration.
December 2025
1 Commits • 1 Features
Dec 1, 2025December 2025: Delivered foundational support for Piecewise Multi-Range logic in facebook/CacheLib by refactoring the piecewise execution path to support multi-range requests while preserving existing request and iteration semantics. Extracted generic piece-related state and behavior into a new base class (GenericPiecesBase) and updated GenericPieces to build on it. This establishes a robust multi-range piece iteration path and paves the way for future performance optimizations and feature enhancements in range-based cache-key processing.
1 Commits • 1 Features
Dec 1, 2025December 2025: Delivered foundational support for Piecewise Multi-Range logic in facebook/CacheLib by refactoring the piecewise execution path to support multi-range requests while preserving existing request and iteration semantics. Extracted generic piece-related state and behavior into a new base class (GenericPiecesBase) and updated GenericPieces to build on it. This establishes a robust multi-range piece iteration path and paves the way for future performance optimizations and feature enhancements in range-based cache-key processing.
December 2025
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Quality Metrics
Correctness96.0%
Maintainability90.0%
Architecture92.0%
Performance90.0%
AI Usage26.0%
Skills & Technologies
Programming Languages
C++
Technical Skills
C++C++ developmentCache ManagementCode RefactoringObject-Oriented ProgrammingSoftware ArchitectureSoftware DesignSoftware DevelopmentSystem DesignUnit Testingcode optimizationcode refactoringobject-oriented programmingpolymorphismsoftware engineering
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