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PROFILE

Daidai

Chang Yuwei developed and optimized core data processing features for the apache/doris repository, focusing on robust external table integration, schema evolution, and high-performance query execution. Over 16 months, Chang engineered solutions for complex data ingestion, including enhancements to Parquet and ORC readers, lazy materialization for Top-N queries, and resilient handling of Hive, Hudi, and MaxCompute sources. Using C++, Java, and SQL, Chang addressed distributed systems challenges, improved error handling, and expanded test coverage to ensure reliability. The work demonstrated deep technical understanding, balancing performance optimization with data correctness, and resulted in more stable, scalable analytics pipelines for diverse data workloads.

Overall Statistics

Feature vs Bugs

51%Features

Repository Contributions

72Total
Bugs
24
Commits
72
Features
25
Lines of code
119,312
Activity Months16

Work History

February 2026

4 Commits • 2 Features

Feb 1, 2026

February 2026 monthly summary for apache/doris development focusing on reader robustness, error reporting, and query planning visibility. Delivered targeted Parquet/ORC reader improvements and enhanced EXPLAIN VERBOSE metrics to improve reliability, debugging efficiency, and performance tuning visibility for data-intensive workloads.

January 2026

8 Commits • 2 Features

Jan 1, 2026

January 2026 (2026-01) monthly summary for apache/doris: Delivered core data processing improvements and stability enhancements across JNI usage, Iceberg ingestion, Parquet reading, and test infrastructure. Focused on increasing data correctness, throughput, and release confidence through targeted feature work, bug fixes, and reliability improvements.

December 2025

4 Commits • 1 Features

Dec 1, 2025

2025-12 monthly summary for apache/doris: Key stability and performance improvements across Parquet/Hudi data paths, with two critical bug fixes and a major Parquet reader enhancement deployed to production. The changes reduce runtime errors, increase data processing throughput, and improve query accuracy for complex Parquet workloads.

November 2025

2 Commits • 2 Features

Nov 1, 2025

Concise monthly overview for 2025-11: Delivered performance-focused features and fixes in Doris, targeting Parquet query performance and JNI scanner efficiency. Key outcomes include enhanced Parquet predicate pushdown with min-max filtering and dynamic runtime filters, deferral of filter application until row group reader instantiation, and JNI Scanners timing optimizations reducing CPU usage during data append operations. These changes improve query latency, lower resource usage, and provide better profiling visibility for ongoing optimizations.

October 2025

2 Commits • 1 Features

Oct 1, 2025

October 2025 monthly summary for apache/doris: Delivered stability improvements and architectural enhancements that reduce outages and improve data workflows. Implemented HDFS Reader stability fix to prevent core dumps during profile collection and added MaxCompute namespace/schema support to enable the new project-schema-table hierarchy with backward compatibility.

September 2025

9 Commits • 4 Features

Sep 1, 2025

September 2025 performance summary focusing on delivering business value through robust data access, performance optimizations, and improved reliability. The month emphasized accelerating data workloads (especially external tables), expanding test coverage, and ensuring international users have seamless access to MaxCompute. Key outcomes include increased reliability of exports, faster query paths for TVFs, and reduced operational risk through stabilized tests and clearer telemetry.

August 2025

2 Commits • 1 Features

Aug 1, 2025

Monthly summary for 2025-08: Delivered performance and reliability improvements in Doris. Implemented TopN runtime filter pushdown for Parquet/ORC and refined row-group filtering to support OR conditions and IN_FILTER pushdown, accelerating analytical queries. Fixed JSON import bug to properly convert boolean values to integers, restoring data correctness for boolean columns loaded from JSON. These changes enhance BI analytics performance and data ingestion reliability, showcasing expertise in performance optimization, data formats, and code refactoring.

July 2025

4 Commits • 1 Features

Jul 1, 2025

July 2025 performance summary for apache/doris. Focused on delivering external table data access enhancements, JNI safety, and build/deploy reliability to improve data ingestion, stability, and cross-environment compatibility. Key features delivered: - Doris External Table Readers: Schema Evolution and Type Conversions. Introduced TableSchemaChangeHelper to enable reading Hudi, Paimon, and Iceberg tables after schema changes, and implemented DATETIMEV2 to numeric conversions for Hive tables in Parquet/ORC formats. (Commits: b66c78cbbe014a7a6251971b1c71fd79f0134765; 2d48f1a229292b3e59358409637f2dd7a14aa75b) Major bugs fixed: - JNI Safety and Exception Handling Improvements: Added comprehensive exception checking and returning Status objects; enhances runtime error detection via -Xcheck:jni. (Commit: 192e9ae3731df41a11df6f406c23d0d5b3dadb1d) - Docker Pipeline Stability and Paimon Version Upgrade: Fixed pipeline instability by upgrading Paimon and uploading JARs to object storage to ensure reliable Maven repository access across environments. (Commit: 5f5aa50fb6b62349795e05e2dd7988eff4526b0e) Overall impact and accomplishments: - Enabled cross-format schema evolution for external tables, improving data freshness and correctness when reading Hudi/Paimon/Iceberg sources; ensured Hive compatibility for DATETIMEV2 in Parquet/ORC. - Reduced runtime JNI errors and improved error visibility, leading to more reliable native interactions. - Stabilized builds and deployments across environments by ensuring artifact availability and consistent Paimon versions, reducing deployment risk. Technologies/skills demonstrated: - C++ JNI safety, Java/C++ interop, error handling patterns, Parquet/ORC data formats, and cross-format schema evolution. - Data ingestion and governance with external tables, and robust CI/CD via Dockerized pipelines and Maven artifacts.

June 2025

3 Commits

Jun 1, 2025

June 2025 monthly summary for apache/doris focusing on stabilizing external table workflows and ensuring accurate schema handling for Hudi-backed data. Delivered critical fixes that boost reliability in distributed deployments, improve data integrity, and reduce query-time anomalies across multi-backend configurations.

May 2025

1 Commits • 1 Features

May 1, 2025

Concise monthly summary for 2025-05 focusing on delivering a high-impact feature for Top-N query performance, strong test coverage, and measurable improvements in memory usage and execution speed. Highlights business value delivered to the apache/doris project and the technical work completed this month.

April 2025

5 Commits • 2 Features

Apr 1, 2025

April 2025 monthly summary for apache/doris. Focused on delivering robust JSON ingestion through Hive JsonSerDe, stabilizing Parquet/ORC readers, and enhancing deserialization safety. The work improves data ingestion reliability, reduces runtime crashes, and broadens test coverage for core data reading paths.

March 2025

5 Commits • 2 Features

Mar 1, 2025

March 2025 performed targeted reliability and interoperability work for the apache/doris repository, focusing on data ingestion robustness, cross-format schema evolution, and MaxCompute integration. Key outcomes include Parquet ingestion robustness improvements, expanded MaxCompute timestamp support with safe handling, and unified top-level schema changes across Iceberg, Paimon, and Hudi. These efforts reduce ingestion failures, broaden external data source compatibility, and streamline schema migrations for analytics pipelines.

February 2025

4 Commits • 1 Features

Feb 1, 2025

February 2025 highlights for apache/doris: Delivered a targeted feature to standardize cross-format type conversions during schema changes (ORC/Parquet), and fixed three critical reliability issues impacting data correctness and query reliability: HMS events stability with meta cache disabled, Parquet complex type cross-page null-map accuracy, and MaxCompute partition column ordering. These changes improve data correctness, partition pruning reliability, and cross-format compatibility, reducing post-change errors and enhancing operational stability for users relying on ORC/Parquet schemas and MaxCompute external tables.

January 2025

6 Commits • 2 Features

Jan 1, 2025

Month: 2025-01 – This period delivered reliability, data correctness, and Hive compatibility improvements for apache/doris. Key features delivered include HTTP API resilience in Kubernetes (followers now directly request the master for API calls, reducing client-to-master failure risk), Hive 4 transactional tables support with ACID optimizations (read support for Hive 4 transactional tables, insert_only read fixes, and full-ACID query optimizations), and MetaCache invalidation correctness improvements. Major bugs fixed encompassed metaCache stale data issues, Hive translation instability cases, hive catalog follower event delivery, and edge-case fixes for full-ACID queries (e.g., select count(*)). Overall impact: increased stability and reliability in Kubernetes deployments, expanded Hive transactional workload support, and stronger metadata correctness, leading to better operational efficiency and data integrity. Technologies/skills demonstrated: Kubernetes API routing resilience, Hive 4/ACID, metadata caching (metaCache), and regression testing.

December 2024

11 Commits • 2 Features

Dec 1, 2024

December 2024: Delivered targeted performance, reliability, and data-source compatibility enhancements for apache/doris, focusing on faster MaxCompute reads, safer handling of non-UTF-8 data, and more robust multi-backend query operations. Completed several partition pruning hardening for Hudi/Iceberg and improved startup and test stability.

November 2024

2 Commits • 1 Features

Nov 1, 2024

Monthly summary for 2024-11 (apache/doris): delivered key stability and data-access improvements including a memory-leak fix in JVM metrics monitoring and enhanced Hive JSON reader for JSON tables. These changes reduce memory pressure, improve reliability, and broaden data access via Hive catalogs. Technologies used include JNI/JVM metrics, Java, JSON parsing, and Hive catalog integration. Business value includes improved production stability, faster data loading, and better compatibility with Hive-backed JSON datasets.

Activity

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Quality Metrics

Correctness88.4%
Maintainability81.6%
Architecture81.6%
Performance78.8%
AI Usage23.4%

Skills & Technologies

Programming Languages

C++GroovyHQLJavaSQLShellThrift

Technical Skills

ACID TransactionsAPI DesignAPI IntegrationBackend DevelopmentBug FixBug FixingBuild SystemsC++C++ DevelopmentC++ developmentC++ programmingCI/CDCachingCloud ComputingCloud Integration

Repositories Contributed To

2 repos

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

apache/doris

Nov 2024 Feb 2026
16 Months active

Languages Used

C++JavaSQLGroovyThriftHQLShell

Technical Skills

Complex Data Types HandlingData Serialization/DeserializationDebuggingDistributed SystemsFile Format HandlingHive Integration

doris

Sep 2025 Sep 2025
1 Month active

Languages Used

GroovySQL

Technical Skills

Backend DevelopmentSQLTesting