percona/percona-server-mongodb
Nov 2024 – Mar 2026
15 Months active
Languages Used
C++JavaScriptBazelShellIDLYAMLMarkdown
Technical Skills
Backend DevelopmentBuild System ManagementC++ DevelopmentCode RefactoringDatabase InternalsDebugging
HanaPearlman
PROFILE
Hanapearlman
Hana Pearlman contributed to the percona/percona-server-mongodb repository by engineering features and fixes that advanced query optimization, diagnostics, and privacy in MongoDB’s backend. Over 15 months, she delivered enhancements such as privacy-focused log redaction, robust join and query planner improvements, and expanded test coverage for aggregation and join operations. Her work involved deep C++ development, JavaScript testing, and build automation, emphasizing type safety, observability, and maintainability. By refactoring core components and introducing new diagnostic and optimization utilities, Hana addressed performance, reliability, and compliance challenges, demonstrating a thorough understanding of database internals and a methodical approach to backend system evolution.
Overall Statistics
Feature vs Bugs
72%Features
Repository Contributions
59Total
Bugs
9
Commits
59
Features
23
Lines of code
25,140
Activity Months15
Your Network
586 peopleSame Organization
@mongodb.com339
Shared Repositories
247
Work History
March 2026
1 Commits • 1 Features
Mar 1, 2026March 2026 monthly summary for percona/percona-server-mongodb: - Focus on implementing safer node handling in the join graph with a new NodeSet type and accompanying tests. This reduces implicit NodeId usage, improving API safety and maintainability. - Major bugs fixed: none reported for this repository this month. - Impact: strengthens core data-structure safety in the join graph, reduces risk of subtle construction errors, and provides regression protection through tests, enabling more reliable query planning and future feature work. - Technologies/skills demonstrated: C++ type-safety patterns, unit testing, test-driven development, and integration with join-graph architecture.
1 Commits • 1 Features
Mar 1, 2026March 2026 monthly summary for percona/percona-server-mongodb: - Focus on implementing safer node handling in the join graph with a new NodeSet type and accompanying tests. This reduces implicit NodeId usage, improving API safety and maintainability. - Major bugs fixed: none reported for this repository this month. - Impact: strengthens core data-structure safety in the join graph, reduces risk of subtle construction errors, and provides regression protection through tests, enabling more reliable query planning and future feature work. - Technologies/skills demonstrated: C++ type-safety patterns, unit testing, test-driven development, and integration with join-graph architecture.
March 2026
February 2026
4 Commits • 2 Features
Feb 1, 2026February 2026 highlights for percona/percona-server-mongodb: focused on reliability of input handling and performance improvements in the join optimizer. Delivered a bug fix to preserve input integrity in the jstest helper, enabling callers to rely on unmodified data. Implemented two key optimizer enhancements to boost join performance and flexibility: (1) MongoDB Join Optimization: Enable $lookup without explicit join predicates, reducing planner constraints and broadening usable join patterns; and (2) NDV-based Join Optimization Enhancements, introducing a helper to detect NDV-based uniqueness and a short-circuit path for NDV estimation when uniqueness is known, speeding up join planning and execution. These changes are supported by targeted commits across the repository and align with business goals around faster query performance and more robust data tooling. Key achievements include improved reliability of test pipelines, more flexible and efficient join processing, and reduced compute overhead in planning complex aggregations.
February 2026
4 Commits • 2 Features
Feb 1, 2026February 2026 highlights for percona/percona-server-mongodb: focused on reliability of input handling and performance improvements in the join optimizer. Delivered a bug fix to preserve input integrity in the jstest helper, enabling callers to rely on unmodified data. Implemented two key optimizer enhancements to boost join performance and flexibility: (1) MongoDB Join Optimization: Enable $lookup without explicit join predicates, reducing planner constraints and broadening usable join patterns; and (2) NDV-based Join Optimization Enhancements, introducing a helper to detect NDV-based uniqueness and a short-circuit path for NDV estimation when uniqueness is known, speeding up join planning and execution. These changes are supported by targeted commits across the repository and align with business goals around faster query performance and more robust data tooling. Key achievements include improved reliability of test pipelines, more flexible and efficient join processing, and reduced compute overhead in planning complex aggregations.
January 2026
11 Commits • 2 Features
Jan 1, 2026January 2026 monthly summary focused on delivering stable, observable, and explainable improvements to the join optimizer and plan visibility in Percona Server for MongoDB. Key outcomes include robust support for cycles, disconnected graphs, and absorbed filters with safe fallbacks; expanded test coverage and enhanced logging; and enhanced explain plans with cardinality and cost estimates to improve planning and performance visibility. These changes reduce the risk of suboptimal or unsafe optimizations, increase reliability for graph-based workloads, and provide clearer performance signals for customers.
11 Commits • 2 Features
Jan 1, 2026January 2026 monthly summary focused on delivering stable, observable, and explainable improvements to the join optimizer and plan visibility in Percona Server for MongoDB. Key outcomes include robust support for cycles, disconnected graphs, and absorbed filters with safe fallbacks; expanded test coverage and enhanced logging; and enhanced explain plans with cardinality and cost estimates to improve planning and performance visibility. These changes reduce the risk of suboptimal or unsafe optimizations, increase reliability for graph-based workloads, and provide clearer performance signals for customers.
January 2026
December 2025
8 Commits • 2 Features
Dec 1, 2025December 2025 — Focused advancement of the query optimization stack in percona/percona-server-mongodb. Delivered two feature streams that enhance planning visibility, accuracy, and graph support, with clear traceability to server tickets and commits. The work lays groundwork for faster, more reliable query planning on complex workloads and large data graphs.
December 2025
8 Commits • 2 Features
Dec 1, 2025December 2025 — Focused advancement of the query optimization stack in percona/percona-server-mongodb. Delivered two feature streams that enhance planning visibility, accuracy, and graph support, with clear traceability to server tickets and commits. The work lays groundwork for faster, more reliable query planning on complex workloads and large data graphs.
November 2025
2 Commits • 1 Features
Nov 1, 2025November 2025 highlights for percona/percona-server-mongodb: delivered a targeted MongoDB query planner enhancement and a test compatibility fix to improve reliability and performance across versions. The changes strengthen business value by accelerating complex query execution and stabilizing the test suite during version upgrades.
2 Commits • 1 Features
Nov 1, 2025November 2025 highlights for percona/percona-server-mongodb: delivered a targeted MongoDB query planner enhancement and a test compatibility fix to improve reliability and performance across versions. The changes strengthen business value by accelerating complex query execution and stabilizing the test suite during version upgrades.
November 2025
October 2025
10 Commits • 2 Features
Oct 1, 2025Concise monthly summary for 2025-10 focusing on NDV estimation enhancements for MongoDB queries, related testing infrastructure improvements, and targeted bug fixes in percona/percona-server-mongodb. The work delivered improved NDV accuracy, multi-field capabilities, and robust tests, enabling more reliable query planning and analytics with reduced risk in production.
October 2025
10 Commits • 2 Features
Oct 1, 2025Concise monthly summary for 2025-10 focusing on NDV estimation enhancements for MongoDB queries, related testing infrastructure improvements, and targeted bug fixes in percona/percona-server-mongodb. The work delivered improved NDV accuracy, multi-field capabilities, and robust tests, enabling more reliable query planning and analytics with reduced risk in production.
September 2025
3 Commits • 1 Features
Sep 1, 2025Monthly summary for 2025-09 focused on delivering business value through targeted MongoDB query optimization and query planner correctness improvements in percona/percona-server-mongodb, with strong collaboration and test coverage.
3 Commits • 1 Features
Sep 1, 2025Monthly summary for 2025-09 focused on delivering business value through targeted MongoDB query optimization and query planner correctness improvements in percona/percona-server-mongodb, with strong collaboration and test coverage.
September 2025
June 2025
2 Commits • 1 Features
Jun 1, 2025June 2025 — percona/percona-server-mongodb: Delivered stability and performance improvements focused on CI reliability and aggregation query processing. Outcomes include (1) CI stability for the TSAN essential variant by excluding TSAN-incompatible tests to prevent known CI failures, and (2) a significant optimization improvement in the Query Optimizer with Nested Path Tracking in MatchExpression to enable safer and more effective reordering of aggregation pipeline stages, supported by new tests for scenarios where $match predicates on group keys cannot be pushed down. Overall impact: Reduced CI noise and faster feedback cycles, improved correctness and performance of common aggregation workloads, and strengthened test coverage for complex path tracking in expressions. Technologies/skills demonstrated: TSAN/CI test hygiene, query optimizer internals, path tracking in expression trees, test generation and validation for optimizer rewrites, commit discipline.
June 2025
2 Commits • 1 Features
Jun 1, 2025June 2025 — percona/percona-server-mongodb: Delivered stability and performance improvements focused on CI reliability and aggregation query processing. Outcomes include (1) CI stability for the TSAN essential variant by excluding TSAN-incompatible tests to prevent known CI failures, and (2) a significant optimization improvement in the Query Optimizer with Nested Path Tracking in MatchExpression to enable safer and more effective reordering of aggregation pipeline stages, supported by new tests for scenarios where $match predicates on group keys cannot be pushed down. Overall impact: Reduced CI noise and faster feedback cycles, improved correctness and performance of common aggregation workloads, and strengthened test coverage for complex path tracking in expressions. Technologies/skills demonstrated: TSAN/CI test hygiene, query optimizer internals, path tracking in expression trees, test generation and validation for optimizer rewrites, commit discipline.
May 2025
2 Commits • 1 Features
May 1, 2025May 2025 highlights for percona/percona-server-mongodb: Improved stability and reduced configuration complexity through targeted code changes in the BSON cursor path and SBE knobs. Implemented a bug fix to initialize BSONObjCursorAppender.objSize to 0, preventing issues from uninitialized data (SERVER-104917). Removed deprecated SBE query knobs to simplify configuration and reduce maintenance burden (SERVER-105471). These changes contribute to safer defaults, fewer runtime errors, and smoother onboarding for engineers. Commits touched include fe27f241aac257b76c5a1e012b952fd46567d221 and 176875d13821ee26827f45ec444398bf721cd352.
2 Commits • 1 Features
May 1, 2025May 2025 highlights for percona/percona-server-mongodb: Improved stability and reduced configuration complexity through targeted code changes in the BSON cursor path and SBE knobs. Implemented a bug fix to initialize BSONObjCursorAppender.objSize to 0, preventing issues from uninitialized data (SERVER-104917). Removed deprecated SBE query knobs to simplify configuration and reduce maintenance burden (SERVER-105471). These changes contribute to safer defaults, fewer runtime errors, and smoother onboarding for engineers. Commits touched include fe27f241aac257b76c5a1e012b952fd46567d221 and 176875d13821ee26827f45ec444398bf721cd352.
May 2025
April 2025
1 Commits • 1 Features
Apr 1, 2025April 2025: Implemented privacy-focused log redaction in percona-server-mongodb to mask sensitive data in logs, including query-owned and pipeline execution details. This directly reduces exposure risk and supports privacy/compliance objectives in production environments. The change is tracked under SERVER-103319 with commit bb9afabfb7e03e080981ded57d21aa7f65fde0f5 and associated work referenced by #35247.
April 2025
1 Commits • 1 Features
Apr 1, 2025April 2025: Implemented privacy-focused log redaction in percona-server-mongodb to mask sensitive data in logs, including query-owned and pipeline execution details. This directly reduces exposure risk and supports privacy/compliance objectives in production environments. The change is tracked under SERVER-103319 with commit bb9afabfb7e03e080981ded57d21aa7f65fde0f5 and associated work referenced by #35247.
March 2025
1 Commits • 1 Features
Mar 1, 2025March 2025 focused on enhancing query diagnostics and reliability for the Percona Server for MongoDB repository. Delivered a targeted feature set that improves visibility into query planning and debugging, enabling faster issue triage and more stable releases. The work lays groundwork for deeper observability and maintainability in future sprints, directly contributing to reduced MTTR and higher confidence in production deployments.
1 Commits • 1 Features
Mar 1, 2025March 2025 focused on enhancing query diagnostics and reliability for the Percona Server for MongoDB repository. Delivered a targeted feature set that improves visibility into query planning and debugging, enabling faster issue triage and more stable releases. The work lays groundwork for deeper observability and maintainability in future sprints, directly contributing to reduced MTTR and higher confidence in production deployments.
March 2025
February 2025
3 Commits • 3 Features
Feb 1, 2025February 2025 for percona/percona-server-mongodb delivered targeted reliability and validation enhancements: expanded unit test coverage for plan statistics, enhanced explain-plan diagnostics for failures, and added retry resilience in the query-tester sparse-checkout flow. These changes improve correctness validation, accelerate debugging of failing queries, and increase CI/test stability, delivering measurable business value in plan accuracy, reliability, and throughput of test cycles.
February 2025
3 Commits • 3 Features
Feb 1, 2025February 2025 for percona/percona-server-mongodb delivered targeted reliability and validation enhancements: expanded unit test coverage for plan statistics, enhanced explain-plan diagnostics for failures, and added retry resilience in the query-tester sparse-checkout flow. These changes improve correctness validation, accelerate debugging of failing queries, and increase CI/test stability, delivering measurable business value in plan accuracy, reliability, and throughput of test cycles.
January 2025
3 Commits • 2 Features
Jan 1, 2025January 2025 monthly summary for percona/percona-server-mongodb focusing on delivering privacy-first logging improvements and enhanced diagnostics tooling. Implemented data redaction enhancements in query logs and restructured diagnostic logging for maintainability and clearer observability across deployments.
3 Commits • 2 Features
Jan 1, 2025January 2025 monthly summary for percona/percona-server-mongodb focusing on delivering privacy-first logging improvements and enhanced diagnostics tooling. Implemented data redaction enhancements in query logs and restructured diagnostic logging for maintainability and clearer observability across deployments.
January 2025
December 2024
2 Commits • 1 Features
Dec 1, 2024Monthly summary for 2024-12 focusing on observability improvements in percona/percona-server-mongodb. Key features delivered include enhanced diagnostic logging for tassert failures across CRUD, explain, and sharded operations, driven by a refactor of the tassert logging mechanism and the introduction of a centralized diagnostic helper utility.
December 2024
2 Commits • 1 Features
Dec 1, 2024Monthly summary for 2024-12 focusing on observability improvements in percona/percona-server-mongodb. Key features delivered include enhanced diagnostic logging for tassert failures across CRUD, explain, and sharded operations, driven by a refactor of the tassert logging mechanism and the introduction of a centralized diagnostic helper utility.
November 2024
6 Commits • 2 Features
Nov 1, 20242024-11 monthly summary for percona/percona-server-mongodb: Key features delivered and major fixes, with business value and technical impact. Focus on test reliability, shard-key query robustness, maintenance cleanup, and enhanced diagnostics/logging with privacy redaction. Demonstrated skills in code maintenance, refactoring, observability, and privacy-conscious logging.
6 Commits • 2 Features
Nov 1, 20242024-11 monthly summary for percona/percona-server-mongodb: Key features delivered and major fixes, with business value and technical impact. Focus on test reliability, shard-key query robustness, maintenance cleanup, and enhanced diagnostics/logging with privacy redaction. Demonstrated skills in code maintenance, refactoring, observability, and privacy-conscious logging.
November 2024
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Quality Metrics
Correctness93.0%
Maintainability85.8%
Architecture88.2%
Performance82.2%
AI Usage23.8%
Skills & Technologies
Programming Languages
BazelC++IDLJavaScriptMarkdownShellYAML
Technical Skills
Aggregation FrameworkBackend DevelopmentBuild AutomationBuild System ConfigurationBuild System ManagementC++C++ DevelopmentC++ developmentC++ programmingCI/CD ConfigurationCode OrganizationCode RefactoringData RedactionDatabase AdministrationDatabase Debugging
Repositories Contributed To
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