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Wenzhi Feng

PROFILE

Wenzhi Feng

Worked on core backend features for Apache Pulsar and BookKeeper, focusing on performance optimization, rate limiting, and failover efficiency. In apache/pulsar, introduced AtomicLong-based delayed message counting to reduce CPU usage and added observability for production diagnostics. Developed rate limiting for ledger deletions and metadata garbage collection in both Pulsar and apache/bookkeeper, using new configuration parameters to stabilize ZooKeeper load during heavy operations. Enhanced client failover logic to prevent unnecessary reconnections, improving resource usage across datastax/pulsar and apache/pulsar. Leveraged Java, concurrency control, and configuration management, with a test-driven approach to ensure reliability and maintainability in distributed system environments.

Overall Statistics

Feature vs Bugs

80%Features

Repository Contributions

7Total
Bugs
1
Commits
7
Features
4
Lines of code
291
Activity Months4

Your Network

800 people

Work History

January 2026

2 Commits • 1 Features

Jan 1, 2026

January 2026 monthly summary focusing on delivering efficiency improvements and stability for Pulsar client failover across two repositories. The work centered on preventing unnecessary reconnections during ControlledClusterFailover by initializing the current configuration from the Pulsar client and aligning connection management with scheduled checks, delivering measurable improvements in failover efficiency and resource usage.

October 2025

2 Commits • 1 Features

Oct 1, 2025

Month 2025-10 – Apache Pulsar (pulse/ledger deletions) Summary: Delivered Ledger Deletion Rate Limiting to prevent ZooKeeper pressure during large topic retention reductions. Introduced a new configuration parameter managedLedgerDeleteMaxConcurrentRequests to govern concurrency of ledger deletions at the broker level. The feature is backward/forward compatible and enabled by default, and is applied across Pulsar broker and BookKeeper broker to stabilize performance under heavy delete load. This work reduces operational risk during retention scale-down and improves overall cluster reliability. Key references: commits implementing PIP-444 for rate limiting the deletion of ledgers to alleviate zk pressure (60eb20d4b998171abde2e3d3750f41d4aeab21c7) and broker-focused changes (ee33c99606e8f573dc55f47529e7c209bd8194e3).

August 2025

1 Commits • 1 Features

Aug 1, 2025

2025-08 monthly summary for apache/bookkeeper. Key feature delivered: BookKeeper Metadata Garbage Collection Rate Limiting (gcMetadataOpRateLimit) to cap metadata operations during GC, reducing ZooKeeper load. Changes included updates to ScanAndCompareGarbageCollector.java and ServerConfiguration.java, plus a new test validating rate limiting. No major bugs fixed this month. Impact: improved cluster stability and throughput during GC, lower risk of ZooKeeper saturation. Technologies demonstrated: Java, ZooKeeper, GC orchestration, test-driven development, configuration management. Business value: more predictable maintenance windows, fewer GC-induced outages, and better operator experience.

June 2025

2 Commits • 1 Features

Jun 1, 2025

June 2025 monthly summary for apache/pulsar: Key feature delivery focused on performance optimization and observability in InMemoryDelayedDeliveryTracker. Replaced delayed messages count computation with an AtomicLong to reduce CPU usage and added observability by logging discrepancies when internal counts diverge from delayedMessagesCount. This work improves throughput under heavy delayed delivery loads and provides faster diagnosability in production.

Activity

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Quality Metrics

Correctness92.8%
Maintainability85.8%
Architecture80.0%
Performance90.0%
AI Usage20.0%

Skills & Technologies

Programming Languages

Java

Technical Skills

Backend DevelopmentBrokerConcurrencyConcurrency ControlConfiguration ManagementDistributed SystemsJavaLoggingMessage QueuesPerformance OptimizationRate LimitingSoftware DevelopmentSystem AdministrationUnit Testingclient-side development

Repositories Contributed To

3 repos

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

apache/pulsar

Jun 2025 Jan 2026
3 Months active

Languages Used

Java

Technical Skills

Backend DevelopmentBrokerConcurrencyLoggingMessage QueuesPerformance Optimization

apache/bookkeeper

Aug 2025 Aug 2025
1 Month active

Languages Used

Java

Technical Skills

Backend DevelopmentConfiguration ManagementRate LimitingSystem Administration

datastax/pulsar

Jan 2026 Jan 2026
1 Month active

Languages Used

Java

Technical Skills

JavaSoftware DevelopmentUnit Testing