percona/percona-server-mongodb
Oct 2024 – Dec 2025
13 Months active
Languages Used
JavaScriptYAMLIDLC++yamlShellPython
Technical Skills
Backend DevelopmentConfiguration ManagementDatabase TestingShardingDatabase AdministrationDatabase Management
Janna Golden
PROFILE
Janna Golden
Janna Golden contributed to the percona/percona-server-mongodb repository by engineering robust backend features and reliability improvements for sharded clusters and resharding workflows. She implemented targeted mirrored reads, enhanced OpenTelemetry tracing, and modularized resharding logic to improve maintainability and observability. Using C++, JavaScript, and YAML, Janna refactored error handling, optimized test automation, and introduced new configuration management strategies to reduce operational risk and improve data consistency. Her work addressed concurrency, database internals, and distributed systems challenges, resulting in more stable migrations, clearer logging, and deterministic CI cycles. The depth of her contributions reflects strong system design and testing expertise.
Overall Statistics
Feature vs Bugs
78%Features
Repository Contributions
46Total
Bugs
6
Commits
46
Features
21
Lines of code
16,030
Activity Months13
Your Network
247 peopleShared Repositories
247
Work History
December 2025
1 Commits • 1 Features
Dec 1, 2025Month 2025-12: Focused on reducing log noise in the ReshardingCoordinator to improve operational clarity and troubleshooting efficiency in the percona-server-mongodb deployment.
1 Commits • 1 Features
Dec 1, 2025Month 2025-12: Focused on reducing log noise in the ReshardingCoordinator to improve operational clarity and troubleshooting efficiency in the percona-server-mongodb deployment.
December 2025
November 2025
5 Commits • 3 Features
Nov 1, 2025Month: 2025-11 summary for percona/percona-server-mongodb focusing on resharding and sharded-cluster data integrity. Delivered three core features to strengthen maintainability, data movement reliability, and future feature readiness: (1) Resharding modularization into a dedicated data_movement module with increased public API visibility to improve maintainability and future work; (2) Repair Sharded Collection Chunks History command, updating data_movement structures and IDL to support a robust data repair workflow; (3) Causal Consistency Module with Logical Time to improve data integrity and synchronization across sharded clusters. These changes reduce operational risk, accelerate feature delivery, and improve correctness under production workloads.
November 2025
5 Commits • 3 Features
Nov 1, 2025Month: 2025-11 summary for percona/percona-server-mongodb focusing on resharding and sharded-cluster data integrity. Delivered three core features to strengthen maintainability, data movement reliability, and future feature readiness: (1) Resharding modularization into a dedicated data_movement module with increased public API visibility to improve maintainability and future work; (2) Repair Sharded Collection Chunks History command, updating data_movement structures and IDL to support a robust data repair workflow; (3) Causal Consistency Module with Logical Time to improve data integrity and synchronization across sharded clusters. These changes reduce operational risk, accelerate feature delivery, and improve correctness under production workloads.
October 2025
9 Commits • 3 Features
Oct 1, 2025October 2025 — Three feature streams delivered in percona/percona-server-mongodb, delivering clear business value through observability, privacy, and test reliability. Key deliverables include end-to-end OpenTelemetry tracing across ingress/egress and builds, privacy-focused encapsulation for resharding internals, and hardened testing infrastructure with replication synchronization and causal-consistency controls. Major bugs fixed: none recorded this month; focus on feature delivery and reliability. Impact: faster incident diagnosis, safer data movement, and more deterministic CI cycles, accelerating safe deployments. Technologies/skills demonstrated: OpenTelemetry integration, trace context propagation, private visibility semantics, enhanced replication testing, and resmoke tracing.
9 Commits • 3 Features
Oct 1, 2025October 2025 — Three feature streams delivered in percona/percona-server-mongodb, delivering clear business value through observability, privacy, and test reliability. Key deliverables include end-to-end OpenTelemetry tracing across ingress/egress and builds, privacy-focused encapsulation for resharding internals, and hardened testing infrastructure with replication synchronization and causal-consistency controls. Major bugs fixed: none recorded this month; focus on feature delivery and reliability. Impact: faster incident diagnosis, safer data movement, and more deterministic CI cycles, accelerating safe deployments. Technologies/skills demonstrated: OpenTelemetry integration, trace context propagation, private visibility semantics, enhanced replication testing, and resmoke tracing.
October 2025
September 2025
2 Commits • 1 Features
Sep 1, 2025September 2025 monthly summary focused on delivering stability and robustness improvements for the MongoDB server within the Percona stack. Work concentrated on two critical areas: resharding process reliability and migration robustness, with concrete commits linked to established issues.
September 2025
2 Commits • 1 Features
Sep 1, 2025September 2025 monthly summary focused on delivering stability and robustness improvements for the MongoDB server within the Percona stack. Work concentrated on two critical areas: resharding process reliability and migration robustness, with concrete commits linked to established issues.
July 2025
2 Commits • 1 Features
Jul 1, 2025July 2025 highlights for percona/percona-server-mongodb: Delivered Targeted Mirrored Reads for MirrorMaestro, refactoring mirroring logic to support targeted and general modes; added helper utilities, statistics, and tests to validate targeted read behavior, enabling selective offloading of read operations and improved read scalability. This work provides a foundation for scalable read workloads across replica sets and reduces read pressure on primary nodes in high-traffic deployments.
2 Commits • 1 Features
Jul 1, 2025July 2025 highlights for percona/percona-server-mongodb: Delivered Targeted Mirrored Reads for MirrorMaestro, refactoring mirroring logic to support targeted and general modes; added helper utilities, statistics, and tests to validate targeted read behavior, enabling selective offloading of read operations and improved read scalability. This work provides a foundation for scalable read workloads across replica sets and reduces read pressure on primary nodes in high-traffic deployments.
July 2025
June 2025
2 Commits • 1 Features
Jun 1, 2025June 2025 (2025-06) monthly summary for percona/percona-server-mongodb: Key features delivered include Topology Version Observer Enhancements with a host cache for MirrorMaestro to improve mirrored reads, plus topology-change notifications to registered callbacks. A targeted-hosts cache based on replica set tags was implemented to optimize read routing. A test refactor ensures notifications are observed before assertions, improving reliability. These changes are backed by commits 5c52b3696738df94888ff5b02a297bf81f2e5022 and a89b4082a949a3c566482ed54ecaa045f336b6a3, including the messages 'SERVER-104848 Make MirrorMaestro track a cache of targeted hosts' and 'SERVER-104848 Wait for Notification before making assertion in topology observer test'. The work enhances read path performance and topology resilience while improving test reliability and traceability.
June 2025
2 Commits • 1 Features
Jun 1, 2025June 2025 (2025-06) monthly summary for percona/percona-server-mongodb: Key features delivered include Topology Version Observer Enhancements with a host cache for MirrorMaestro to improve mirrored reads, plus topology-change notifications to registered callbacks. A targeted-hosts cache based on replica set tags was implemented to optimize read routing. A test refactor ensures notifications are observed before assertions, improving reliability. These changes are backed by commits 5c52b3696738df94888ff5b02a297bf81f2e5022 and a89b4082a949a3c566482ed54ecaa045f336b6a3, including the messages 'SERVER-104848 Make MirrorMaestro track a cache of targeted hosts' and 'SERVER-104848 Wait for Notification before making assertion in topology observer test'. The work enhances read path performance and topology resilience while improving test reliability and traceability.
May 2025
7 Commits • 4 Features
May 1, 2025May 2025 monthly summary for percona/percona-server-mongodb focusing on business value and technical achievements. Key features delivered and major improvements: - Sharded cluster operations reliability improvements: increased migration reliability by waiting for chunk deletion in moveChunk-based tests and enabling a retry for resharding on WriteConcernTimeout with refined retry timing to avoid reset issues. This reduces migration-related failures and improves production stability.
7 Commits • 4 Features
May 1, 2025May 2025 monthly summary for percona/percona-server-mongodb focusing on business value and technical achievements. Key features delivered and major improvements: - Sharded cluster operations reliability improvements: increased migration reliability by waiting for chunk deletion in moveChunk-based tests and enabling a retry for resharding on WriteConcernTimeout with refined retry timing to avoid reset issues. This reduces migration-related failures and improves production stability.
May 2025
April 2025
3 Commits • 1 Features
Apr 1, 2025April 2025 monthly summary for percona/percona-server-mongodb. Delivered targeted fixes and code hygiene improvements that stabilize behavior, reduce error surface, and prepare the project for future resharding work. Key outcomes include reverting WriteConcern POC changes to restore prior behavior, enforcing shard-key stability during forceRedistribution with reshardCollection to prevent incorrect usage, and removing noexcept to simplify exception handling and improve maintainability. All changes included focused commits and accompanying tests where applicable, contributing to reduced risk in production and clearer maintenance paths.
April 2025
3 Commits • 1 Features
Apr 1, 2025April 2025 monthly summary for percona/percona-server-mongodb. Delivered targeted fixes and code hygiene improvements that stabilize behavior, reduce error surface, and prepare the project for future resharding work. Key outcomes include reverting WriteConcern POC changes to restore prior behavior, enforcing shard-key stability during forceRedistribution with reshardCollection to prevent incorrect usage, and removing noexcept to simplify exception handling and improve maintainability. All changes included focused commits and accompanying tests where applicable, contributing to reduced risk in production and clearer maintenance paths.
March 2025
2 Commits
Mar 1, 2025March 2025: Focused on improving replication reliability and shard-key immutability handling in percona/percona-server-mongodb. Implemented lastOp handling for no-op writes, refactored write concern accounting for aggregation paths, ensured secondaries do not wait for write concern on forwarded operations, and added tests for shard-key immutability scenarios. Improved test synchronization with awaitReplication and expanded coverage for shard-key updates, delivering measurable improvements in data consistency and operation reliability.
2 Commits
Mar 1, 2025March 2025: Focused on improving replication reliability and shard-key immutability handling in percona/percona-server-mongodb. Implemented lastOp handling for no-op writes, refactored write concern accounting for aggregation paths, ensured secondaries do not wait for write concern on forwarded operations, and added tests for shard-key immutability scenarios. Improved test synchronization with awaitReplication and expanded coverage for shard-key updates, delivering measurable improvements in data consistency and operation reliability.
March 2025
February 2025
5 Commits • 2 Features
Feb 1, 2025February 2025 monthly summary for percona/percona-server-mongodb focusing on testing improvements, shard key analysis, and write concern coverage. Delivered key features, fixed legacy test infrastructure, and enhanced reliability with broader test coverage across sharding configurations, supporting safer and more robust deployments.
February 2025
5 Commits • 2 Features
Feb 1, 2025February 2025 monthly summary for percona/percona-server-mongodb focusing on testing improvements, shard key analysis, and write concern coverage. Delivered key features, fixed legacy test infrastructure, and enhanced reliability with broader test coverage across sharding configurations, supporting safer and more robust deployments.
December 2024
4 Commits • 2 Features
Dec 1, 2024Monthly summary for 2024-12 focusing on business value and technical achievements for repo percona/percona-server-mongodb. Key features delivered: - Resilient sharding transaction handling: introduced automatic retries for TransientTransactionError in sharding tests; refactored helpers to manage transaction lifecycles, improving test stability and reliability when transient errors occur. Commits: 4834d4842935ff0a00fbe9a12997408a035671af; 0dddff182649f67b272edc32ef357d215837cf34. - Timeseries resharding enabled by default: re-enabled FeatureFlagReshardingForTimeseries by default and removed feature flag checks in tests, standardizing timeseries resharding and aligning with version 8.0. Commits: fa712d3518dc86f6c5a4bdc766d84fd1f0ccbbeb; 3f0d6b5a626ea69aeebf22e88b01fdfc777495ff. Major bugs fixed / quality improvements: - Significantly improved test stability for sharding workflows by adding automatic retries for TransientTransactionError and by refining transaction lifecycle helpers, reducing flaky CI failures. Overall impact and accomplishments: - Reduced test flakiness in sharded environments and established a standard behavior for timeseries resharding across versions, accelerating CI feedback and enabling more reliable release cycles. - Demonstrated end-to-end delivery of two high-impact features with clear traceability to specific issues and commits. Technologies/skills demonstrated: - MongoDB sharding, Transactions, and Timeseries features - Test automation and stabilization (transaction lifecycle helpers, test flag management) - Feature flag usage and defaulting, CI reliability improvements - Traceability to commits and issue IDs (SERVER-97381, SERVER-97896, SERVER-93149, SERVER-29916)
4 Commits • 2 Features
Dec 1, 2024Monthly summary for 2024-12 focusing on business value and technical achievements for repo percona/percona-server-mongodb. Key features delivered: - Resilient sharding transaction handling: introduced automatic retries for TransientTransactionError in sharding tests; refactored helpers to manage transaction lifecycles, improving test stability and reliability when transient errors occur. Commits: 4834d4842935ff0a00fbe9a12997408a035671af; 0dddff182649f67b272edc32ef357d215837cf34. - Timeseries resharding enabled by default: re-enabled FeatureFlagReshardingForTimeseries by default and removed feature flag checks in tests, standardizing timeseries resharding and aligning with version 8.0. Commits: fa712d3518dc86f6c5a4bdc766d84fd1f0ccbbeb; 3f0d6b5a626ea69aeebf22e88b01fdfc777495ff. Major bugs fixed / quality improvements: - Significantly improved test stability for sharding workflows by adding automatic retries for TransientTransactionError and by refining transaction lifecycle helpers, reducing flaky CI failures. Overall impact and accomplishments: - Reduced test flakiness in sharded environments and established a standard behavior for timeseries resharding across versions, accelerating CI feedback and enabling more reliable release cycles. - Demonstrated end-to-end delivery of two high-impact features with clear traceability to specific issues and commits. Technologies/skills demonstrated: - MongoDB sharding, Transactions, and Timeseries features - Test automation and stabilization (transaction lifecycle helpers, test flag management) - Feature flag usage and defaulting, CI reliability improvements - Traceability to commits and issue IDs (SERVER-97381, SERVER-97896, SERVER-93149, SERVER-29916)
December 2024
November 2024
3 Commits • 2 Features
Nov 1, 20242024-11 Monthly Summary for percona/percona-server-mongodb: Delivered two core features to improve reliability and scalability in shard deployments, plus reliability improvements to tests. Key outcomes include enabling retryable writes during shard transitions with refined retry logic to prevent duplicates, and enabling timeseries resharding by default to align with system version 8.0. These workstreams reduce operational risk, improve data consistency, and support higher throughput in production. Technical achievements include targeted test stabilization and feature-flag simplification, demonstrated through the following commits: 5527c52731b8024a750304b943b2f2bb40487ec6; 798b21f78ecf5996e6fc1f3cff876c4cf98e94b1; 863dff0fd7cd0d5754898393b0c30e017e3dbb87.
November 2024
3 Commits • 2 Features
Nov 1, 20242024-11 Monthly Summary for percona/percona-server-mongodb: Delivered two core features to improve reliability and scalability in shard deployments, plus reliability improvements to tests. Key outcomes include enabling retryable writes during shard transitions with refined retry logic to prevent duplicates, and enabling timeseries resharding by default to align with system version 8.0. These workstreams reduce operational risk, improve data consistency, and support higher throughput in production. Technical achievements include targeted test stabilization and feature-flag simplification, demonstrated through the following commits: 5527c52731b8024a750304b943b2f2bb40487ec6; 798b21f78ecf5996e6fc1f3cff876c4cf98e94b1; 863dff0fd7cd0d5754898393b0c30e017e3dbb87.
October 2024
1 Commits
Oct 1, 2024October 2024 — Delivered reliability improvements for bulkWrite retry during sharded config transitions in percona/percona-server-mongodb. Implemented resilient retry logic for bulkWrite errors with coverage across multiple retry scenarios and added new test configurations to validate robustness (commit 02cc37bf83436aeb0a4b747944e8583532f194a2; SERVER-95116). Result: improved stability and reduced operational risk during config changes in sharded environments. Technologies demonstrated include MongoDB bulkWrite operations, sharded config transitions, retry/backoff strategies, and expanded test configuration management.
1 Commits
Oct 1, 2024October 2024 — Delivered reliability improvements for bulkWrite retry during sharded config transitions in percona/percona-server-mongodb. Implemented resilient retry logic for bulkWrite errors with coverage across multiple retry scenarios and added new test configurations to validate robustness (commit 02cc37bf83436aeb0a4b747944e8583532f194a2; SERVER-95116). Result: improved stability and reduced operational risk during config changes in sharded environments. Technologies demonstrated include MongoDB bulkWrite operations, sharded config transitions, retry/backoff strategies, and expanded test configuration management.
October 2024
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Quality Metrics
Correctness90.2%
Maintainability86.8%
Architecture87.0%
Performance79.4%
AI Usage22.6%
Skills & Technologies
Programming Languages
C++IDLJavaScriptPythonShellYAMLyaml
Technical Skills
Backend DevelopmentBazelC++C++ DevelopmentC++ developmentC++ programmingCI/CDCode OrganizationCode RefactoringConcurrencyConfiguration ManagementDatabaseDatabase AdministrationDatabase InternalsDatabase Management
Repositories Contributed To
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