apache/druid
May 2025 – Mar 2026
10 Months active
Languages Used
JavaSQLShellPropertiesHTMLPythonYAMLXML
Technical Skills
API DesignBackend DevelopmentConcurrencyCore JavaData ProcessingData Querying
Cece Mei
PROFILE
Cece Mei
Yingqian Mei contributed to the Apache Druid repository by engineering robust backend features and enhancements focused on data segmentation, query optimization, and security. Over ten months, Yingqian designed and implemented improvements such as row-based compaction policies, segment-specific querying, and strict JSON type validation, using Java and SQL to ensure data correctness and efficient analytics. Their work included refactoring for modularity, expanding test coverage, and optimizing memory and storage management. By addressing concurrency, authorization, and benchmarking, Yingqian delivered solutions that improved system reliability and maintainability, demonstrating a deep understanding of distributed systems and backend development in a complex data platform.
Overall Statistics
Feature vs Bugs
71%Features
Repository Contributions
36Total
Bugs
8
Commits
36
Features
20
Lines of code
20,478
Activity Months10
Your Network
65 peopleWork History
March 2026
1 Commits • 1 Features
Mar 1, 2026March 2026 — Apache Druid (apache/druid): Delivered Data Segment Compaction Policy Enhancements to streamline data maintenance and boost query performance. Implemented row-based compaction eligibility filtering and updated rules based on row counts and segment fragmentation to reduce fragmentation and improve analytics throughput. The changes were implemented in a focused commit (5f77596d42bc38173dbff3a491d9a035094d9d6c) with accompanying documentation updates. No major bugs fixed this month; ongoing work focused on stability and performance around compaction.
1 Commits • 1 Features
Mar 1, 2026March 2026 — Apache Druid (apache/druid): Delivered Data Segment Compaction Policy Enhancements to streamline data maintenance and boost query performance. Implemented row-based compaction eligibility filtering and updated rules based on row counts and segment fragmentation to reduce fragmentation and improve analytics throughput. The changes were implemented in a focused commit (5f77596d42bc38173dbff3a491d9a035094d9d6c) with accompanying documentation updates. No major bugs fixed this month; ongoing work focused on stability and performance around compaction.
March 2026
February 2026
1 Commits • 1 Features
Feb 1, 2026February 2026 – Apache Druid: Delivered MSQ Compaction Reliability and Test Coverage Improvements in the indexing-service. Focused on stabilizing MSQ compaction state, native interval locking, and expanding test coverage to ensure correct handling of non-aligned intervals and segment locking. The changes enhance robustness and correctness of compaction tasks, reducing operational risk in the indexing pipeline. Key commit references provided for traceability.
February 2026
1 Commits • 1 Features
Feb 1, 2026February 2026 – Apache Druid: Delivered MSQ Compaction Reliability and Test Coverage Improvements in the indexing-service. Focused on stabilizing MSQ compaction state, native interval locking, and expanding test coverage to ensure correct handling of non-aligned intervals and segment locking. The changes enhance robustness and correctness of compaction tasks, reducing operational risk in the indexing pipeline. Key commit references provided for traceability.
January 2026
2 Commits • 1 Features
Jan 1, 20262026-01 monthly summary: Delivered data segmentation enhancements in the Apache Druid repository, introducing totalRows metadata to DataSegment and enabling segment-specific querying in TableInputSpec with validation for non-empty segment lists. Implemented thorough tests and aligned changes to maintain stability while expanding capabilities. These improvements deliver tangible business value by providing accurate row counts for analytics, enabling more targeted queries, and reducing risk of invalid segment queries, which supports better reporting, capacity planning, and dashboard performance. The work demonstrates strong collaboration, code quality hygiene, and end-to-end validation across the data segmentation path.
2 Commits • 1 Features
Jan 1, 20262026-01 monthly summary: Delivered data segmentation enhancements in the Apache Druid repository, introducing totalRows metadata to DataSegment and enabling segment-specific querying in TableInputSpec with validation for non-empty segment lists. Implemented thorough tests and aligned changes to maintain stability while expanding capabilities. These improvements deliver tangible business value by providing accurate row counts for analytics, enabling more targeted queries, and reducing risk of invalid segment queries, which supports better reporting, capacity planning, and dashboard performance. The work demonstrates strong collaboration, code quality hygiene, and end-to-end validation across the data segmentation path.
January 2026
December 2025
4 Commits • 2 Features
Dec 1, 2025December 2025: Strengthened data correctness and storage efficiency in Apache Druid through targeted nested data enhancements, improved serialization/deserialization reliability, and backward-compatibility fixes. Key outcomes include expanded test coverage for object-storage encoding, configurable bitmap index types for nested numeric fields, and Java 11 compatibility across the codebase.
December 2025
4 Commits • 2 Features
Dec 1, 2025December 2025: Strengthened data correctness and storage efficiency in Apache Druid through targeted nested data enhancements, improved serialization/deserialization reliability, and backward-compatibility fixes. Key outcomes include expanded test coverage for object-storage encoding, configurable bitmap index types for nested numeric fields, and Java 11 compatibility across the codebase.
October 2025
6 Commits • 3 Features
Oct 1, 2025October 2025 (2025-10) focused on delivering safer JSON processing, memory-efficient data handling, and release-readiness while strengthening security and performance observability. Key outcomes include new strict JSON type validation, the ability to compute JSON from dictionaries to reduce storage footprints, memory safeguards for dictionary building, a major release prep through version bump, and enhanced benchmarking for encoding formats to guide choices. Security and licensing updates addressed CVE concerns and ensured toolchain compatibility.
6 Commits • 3 Features
Oct 1, 2025October 2025 (2025-10) focused on delivering safer JSON processing, memory-efficient data handling, and release-readiness while strengthening security and performance observability. Key outcomes include new strict JSON type validation, the ability to compute JSON from dictionaries to reduce storage footprints, memory safeguards for dictionary building, a major release prep through version bump, and enhanced benchmarking for encoding formats to guide choices. Security and licensing updates addressed CVE concerns and ensured toolchain compatibility.
October 2025
September 2025
2 Commits • 2 Features
Sep 1, 2025September 2025: Delivered two feature enhancements for apache/druid that improve time-based analytics accuracy and query result ordering, underpinned by careful refactors to granularity mapping and projection compatibility. These changes reduce inconsistencies in aggregations and provide more flexible query ordering, delivering measurable business value to dashboards and analytical workflows.
September 2025
2 Commits • 2 Features
Sep 1, 2025September 2025: Delivered two feature enhancements for apache/druid that improve time-based analytics accuracy and query result ordering, underpinned by careful refactors to granularity mapping and projection compatibility. These changes reduce inconsistencies in aggregations and provide more flexible query ordering, delivering measurable business value to dashboards and analytical workflows.
August 2025
3 Commits • 3 Features
Aug 1, 2025Month: 2025-08 — Security hardening, architectural refactors, and testability improvements in apache/druid. Delivered three targeted changes that strengthen authorization controls, decouple resource query result creation, and optimize projection filter handling. All changes accompanied by updated tests to ensure correctness and reduce regression risk, laying groundwork for future feature work and performance improvements.
3 Commits • 3 Features
Aug 1, 2025Month: 2025-08 — Security hardening, architectural refactors, and testability improvements in apache/druid. Delivered three targeted changes that strengthen authorization controls, decouple resource query result creation, and optimize projection filter handling. All changes accompanied by updated tests to ensure correctness and reduce regression risk, laying groundwork for future feature work and performance improvements.
August 2025
July 2025
8 Commits • 3 Features
Jul 1, 2025July 2025 focused on strengthening data integrity, query robustness, and release readiness for apache/druid. Key features include adding a backward-compatible DataSegment projections field and preserving projection data during reindexing, while preventing duplicates; improvements to the Timeseries Query engine for Granularities.ALL to reduce unnecessary constraints; and robustness enhancements in CountAggregator and required-column handling. In addition, CI/Test Infrastructure stabilization reduced flakiness by updating the base image to OpenJDK 17-slim, removing hard-coded driver configurations, and resolving resource issues. Overall impact: more reliable projection metadata, safer incremental indexes, more correct and performant time-series queries, and faster, more deterministic CI feedback for releases.
July 2025
8 Commits • 3 Features
Jul 1, 2025July 2025 focused on strengthening data integrity, query robustness, and release readiness for apache/druid. Key features include adding a backward-compatible DataSegment projections field and preserving projection data during reindexing, while preventing duplicates; improvements to the Timeseries Query engine for Granularities.ALL to reduce unnecessary constraints; and robustness enhancements in CountAggregator and required-column handling. In addition, CI/Test Infrastructure stabilization reduced flakiness by updating the base image to OpenJDK 17-slim, removing hard-coded driver configurations, and resolving resource issues. Overall impact: more reliable projection metadata, safer incremental indexes, more correct and performant time-series queries, and faster, more deterministic CI feedback for releases.
June 2025
3 Commits • 2 Features
Jun 1, 2025Monthly work summary for 2025-06 focused on delivering secure, maintainable, and auditable data tooling within the Apache Druid project. Key outcomes include security policy enforcement improvements for restricted data sources in join paths, modularization to improve testability, and metadata accuracy enhancements in SegmentAnalysis. The work drives safer data access, faster testing cycles, and more reliable analytics metadata, enabling more confident data sharing and policy enforcement.
3 Commits • 2 Features
Jun 1, 2025Monthly work summary for 2025-06 focused on delivering secure, maintainable, and auditable data tooling within the Apache Druid project. Key outcomes include security policy enforcement improvements for restricted data sources in join paths, modularization to improve testability, and metadata accuracy enhancements in SegmentAnalysis. The work drives safer data access, faster testing cycles, and more reliable analytics metadata, enabling more confident data sharing and policy enforcement.
June 2025
May 2025
6 Commits • 2 Features
May 1, 2025Concise monthly summary for 2025-05 focusing on business value and technical achievements in the Apache Druid repository. Highlights include correctness hardening for non-table-backed segments, engine compatibility improvements for UnionDataSource with native and MSQ engines, search query processing refinements, and strengthened test reliability. These changes reduce runtime errors, improve query accuracy and stability, and prepare the ground for smoother future engine transitions across data workloads.
May 2025
6 Commits • 2 Features
May 1, 2025Concise monthly summary for 2025-05 focusing on business value and technical achievements in the Apache Druid repository. Highlights include correctness hardening for non-table-backed segments, engine compatibility improvements for UnionDataSource with native and MSQ engines, search query processing refinements, and strengthened test reliability. These changes reduce runtime errors, improve query accuracy and stability, and prepare the ground for smoother future engine transitions across data workloads.
Activity
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Quality Metrics
Correctness87.2%
Maintainability84.4%
Architecture84.2%
Performance77.2%
AI Usage26.6%
Skills & Technologies
Programming Languages
HTMLJavaPropertiesPythonSQLShellXMLYAML
Technical Skills
API DesignAPI DevelopmentAuthorizationBackend DevelopmentBenchmarkingBuild AutomationBuild ScriptingCI/CDCode RefactoringColumnar StorageConcurrencyCore JavaData AnalysisData EngineeringData Processing
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