percona/percona-server-mongodb
Oct 2024 – Jun 2026
18 Months active
Languages Used
C++YAMLJavaScriptIDLMarkdownBazel
Technical Skills
Change StreamsCode RefactoringDatabase ManagementSystem AdministrationBackend DevelopmentC++
Haley Connelly
PROFILE
Haley Connelly
Over 18 months, contributed to percona/percona-server-mongodb by designing and delivering features that improved replication, storage engine reliability, and operational observability. Focused on backend development in C++ and JavaScript, the work included refactoring catalog management, implementing UUID-based identifier generation, and enhancing change stream compatibility for replicated collections. Introduced real-time metrics tracking and logical size lifecycle management, leveraging IDL schema design to support hot and cold storage tiers. Addressed test stability and code maintainability through targeted cleanups and robust CI integration. These efforts strengthened data consistency, streamlined system architecture, and enabled safer, more predictable operations in distributed MongoDB environments.
Overall Statistics
Feature vs Bugs
73%Features
Repository Contributions
55Total
Bugs
9
Commits
55
Features
24
Lines of code
22,896
Activity Months18
Your Network
643 peopleWork History
June 2026
8 Commits • 2 Features
Jun 1, 2026June 2026 — Percona Server for MongoDB: Delivered real-time metrics and storage visibility enhancements that improve operations, planning, and reliability. Real-time tailable checkpointing enables oplog-driven updates for size and count metrics, increasing accuracy and responsiveness. Introduced a hot/cold storage lifecycle with LogicalSizeTracker and IDL-based snapshots, plus a feature flag to enable/disable tracking, providing visibility into storage usage across tiers and facilitating future deprecation of legacy infrastructure. Achieved substantial reliability improvements, stabilizing tests and invariants to reduce risk in metric reporting and checkpointing flows.
8 Commits • 2 Features
Jun 1, 2026June 2026 — Percona Server for MongoDB: Delivered real-time metrics and storage visibility enhancements that improve operations, planning, and reliability. Real-time tailable checkpointing enables oplog-driven updates for size and count metrics, increasing accuracy and responsiveness. Introduced a hot/cold storage lifecycle with LogicalSizeTracker and IDL-based snapshots, plus a feature flag to enable/disable tracking, providing visibility into storage usage across tiers and facilitating future deprecation of legacy infrastructure. Achieved substantial reliability improvements, stabilizing tests and invariants to reduce risk in metric reporting and checkpointing flows.
June 2026
May 2026
1 Commits • 1 Features
May 1, 2026May 2026 monthly summary for percona/percona-server-mongodb focused on feature delivery and impact. Key features delivered: - Prepared Transaction Metrics Tracking (size and count deltas) during commit, improving visibility and state management of metrics for transactions in the oplog. This enables accurate aggregation of metrics for collections involved in transactions. - End-to-end traceability to commit 0b6bb7f48629abf63243086b22095613c6867a50 addressing SERVER-124064. Major bugs fixed: - No explicit major bugs fixed were documented in this month for this repository. Overall impact and accomplishments: - Improves observability and accuracy of transactional metrics, enabling faster issue detection, better capacity planning, and informed performance tuning for transactional workloads. - Strengthens data-driven decision making by providing precise size and count deltas for prepared transactions. Technologies/skills demonstrated: - Database internals familiarity (transactions, oplog handling) - Metrics instrumentation and observability - Git-based traceability and issue linking (SERVER-124064) - Cross-functional collaboration to deliver a focused feature across the repository
May 2026
1 Commits • 1 Features
May 1, 2026May 2026 monthly summary for percona/percona-server-mongodb focused on feature delivery and impact. Key features delivered: - Prepared Transaction Metrics Tracking (size and count deltas) during commit, improving visibility and state management of metrics for transactions in the oplog. This enables accurate aggregation of metrics for collections involved in transactions. - End-to-end traceability to commit 0b6bb7f48629abf63243086b22095613c6867a50 addressing SERVER-124064. Major bugs fixed: - No explicit major bugs fixed were documented in this month for this repository. Overall impact and accomplishments: - Improves observability and accuracy of transactional metrics, enabling faster issue detection, better capacity planning, and informed performance tuning for transactional workloads. - Strengthens data-driven decision making by providing precise size and count deltas for prepared transactions. Technologies/skills demonstrated: - Database internals familiarity (transactions, oplog handling) - Metrics instrumentation and observability - Git-based traceability and issue linking (SERVER-124064) - Cross-functional collaboration to deliver a focused feature across the repository
April 2026
4 Commits • 1 Features
Apr 1, 2026In April 2026, delivered end-to-end transaction size metadata tracking in replication for percona/percona-server-mongodb. This feature adds an OplogEntry SizeMetadata variant, tracks cumulative size and operation counts for involved collections within a transaction, persists size metadata in config.transactions for centralized observability, and writes size information to commitTransaction oplog entries for prepared transactions. These changes enhance observability, capacity planning, durability, and auditability of replicated transactions, enabling better recovery and governance. The work spanned storage, replication, and IDL/schema updates, implemented via four commits to the feature branch.
4 Commits • 1 Features
Apr 1, 2026In April 2026, delivered end-to-end transaction size metadata tracking in replication for percona/percona-server-mongodb. This feature adds an OplogEntry SizeMetadata variant, tracks cumulative size and operation counts for involved collections within a transaction, persists size metadata in config.transactions for centralized observability, and writes size information to commitTransaction oplog entries for prepared transactions. These changes enhance observability, capacity planning, durability, and auditability of replicated transactions, enabling better recovery and governance. The work spanned storage, replication, and IDL/schema updates, implemented via four commits to the feature branch.
April 2026
March 2026
4 Commits • 2 Features
Mar 1, 2026Monthly work summary for 2026-03: Implemented critical oplog enhancements and code cleanups for improved replication reliability and maintainability in percona/percona-server-mongodb. Focus was on features that directly enhance replication performance metrics, reduce code complexity, and lay groundwork for future telemetry and optimization.
March 2026
4 Commits • 2 Features
Mar 1, 2026Monthly work summary for 2026-03: Implemented critical oplog enhancements and code cleanups for improved replication reliability and maintainability in percona/percona-server-mongodb. Focus was on features that directly enhance replication performance metrics, reduce code complexity, and lay groundwork for future telemetry and optimization.
February 2026
3 Commits • 2 Features
Feb 1, 2026February 2026 monthly summary for percona/percona-server-mongodb: Delivered two tightly scoped features that strengthen cross-node consistency and transaction lifecycle visibility, supported by targeted tests and opt-in configurability. These changes reduce the risk of replicated ID leakage during resharding, provide an opt-in mechanism to include replicated IDs in dbhash for cross-node checks, and improve tracking of uncommitted changes in multi-document transactions via a Snapshot decoration, preserving state across lifetimes.
3 Commits • 2 Features
Feb 1, 2026February 2026 monthly summary for percona/percona-server-mongodb: Delivered two tightly scoped features that strengthen cross-node consistency and transaction lifecycle visibility, supported by targeted tests and opt-in configurability. These changes reduce the risk of replicated ID leakage during resharding, provide an opt-in mechanism to include replicated IDs in dbhash for cross-node checks, and improve tracking of uncommitted changes in multi-document transactions via a Snapshot decoration, preserving state across lifetimes.
February 2026
January 2026
1 Commits • 1 Features
Jan 1, 2026January 2026 monthly summary for percona/percona-server-mongodb: Delivered Change Stream Compatibility with recordIdsReplicated collections, enabling robust change stream behavior for collections with the recordIdsReplicated option. Implemented adjustments to tests (removed incompatibility tags and updated assertions) to reflect the new behavior, improving test reliability and coverage. No separate critical bug fixes were recorded; primary focus on feature delivery and test hygiene. Business impact: reduces integration risk for clients relying on change streams with recordIdsReplicated, enabling broader adoption and more predictable stream behavior. Technical highlights: changes to change streams, test suite updates (jstests), commits: 7ebacfca8c5d9cad38682f132752f80378452778; GitOrigin-RevId: 998c7f3872eefd6e696f28d4e256fb0341e62bc6. Repository: percona/percona-server-mongodb.
January 2026
1 Commits • 1 Features
Jan 1, 2026January 2026 monthly summary for percona/percona-server-mongodb: Delivered Change Stream Compatibility with recordIdsReplicated collections, enabling robust change stream behavior for collections with the recordIdsReplicated option. Implemented adjustments to tests (removed incompatibility tags and updated assertions) to reflect the new behavior, improving test reliability and coverage. No separate critical bug fixes were recorded; primary focus on feature delivery and test hygiene. Business impact: reduces integration risk for clients relying on change streams with recordIdsReplicated, enabling broader adoption and more predictable stream behavior. Technical highlights: changes to change streams, test suite updates (jstests), commits: 7ebacfca8c5d9cad38682f132752f80378452778; GitOrigin-RevId: 998c7f3872eefd6e696f28d4e256fb0341e62bc6. Repository: percona/percona-server-mongodb.
December 2025
2 Commits • 1 Features
Dec 1, 2025Monthly summary for 2025-12: Focused delivery in percona/percona-server-mongodb on test infrastructure stabilization and enhanced collection management for replicated deployments. Key outcomes include re-enabled and stabilized tests for the replicated record IDs variant on Amazon Linux 2023 and the introduction of support to create capped collections with the replicate record IDs option. These efforts improved test reliability, reduced regression risk in AL2023 environments, and extended data-management capabilities for replicated setups. Highlights include contributions tied to commits c88293704242578c887c7980133402a7a56d8154 and 7ce708b0d921b603c87b340171611d716979a086, with co-authored collaboration by Yuhong Zhang. Technologies exercised include test infrastructure stabilization, Linux environment validation, and expansion of MongoDB-compatible collection management features.
2 Commits • 1 Features
Dec 1, 2025Monthly summary for 2025-12: Focused delivery in percona/percona-server-mongodb on test infrastructure stabilization and enhanced collection management for replicated deployments. Key outcomes include re-enabled and stabilized tests for the replicated record IDs variant on Amazon Linux 2023 and the introduction of support to create capped collections with the replicate record IDs option. These efforts improved test reliability, reduced regression risk in AL2023 environments, and extended data-management capabilities for replicated setups. Highlights include contributions tied to commits c88293704242578c887c7980133402a7a56d8154 and 7ce708b0d921b603c87b340171611d716979a086, with co-authored collaboration by Yuhong Zhang. Technologies exercised include test infrastructure stabilization, Linux environment validation, and expansion of MongoDB-compatible collection management features.
December 2025
October 2025
1 Commits • 1 Features
Oct 1, 2025Concise monthly summary for 2025-10 focused on feature delivery and its business value for the Percona Server for MongoDB project. No major bugs reported this month; feature work concentrated on WiredTiger engine configurability and its impact on performance tuning and maintainability.
October 2025
1 Commits • 1 Features
Oct 1, 2025Concise monthly summary for 2025-10 focused on feature delivery and its business value for the Percona Server for MongoDB project. No major bugs reported this month; feature work concentrated on WiredTiger engine configurability and its impact on performance tuning and maintainability.
September 2025
1 Commits • 1 Features
Sep 1, 2025September 2025: Delivered a targeted optimization in the Percona Server MongoDB project by removing tenantId tracking from the pre-image truncation logic to enforce single-tenant operation, simplifying the codebase and reducing cross-tenant risk. The change is implemented in percona/percona-server-mongodb with commit b6588f5eaeae5b9e8220a6aaebf336989918507a (SERVER-109191; PR #41003). No major bugs were fixed this month; the focus was a high-value architectural improvement with clear business impact.
1 Commits • 1 Features
Sep 1, 2025September 2025: Delivered a targeted optimization in the Percona Server MongoDB project by removing tenantId tracking from the pre-image truncation logic to enforce single-tenant operation, simplifying the codebase and reducing cross-tenant risk. The change is implemented in percona/percona-server-mongodb with commit b6588f5eaeae5b9e8220a6aaebf336989918507a (SERVER-109191; PR #41003). No major bugs were fixed this month; the focus was a high-value architectural improvement with clear business impact.
September 2025
July 2025
4 Commits • 1 Features
Jul 1, 2025July 2025 monthly summary for percona/percona-server-mongodb focused on strengthening distributed catalog metadata handling, data consistency, and operational robustness across the server core. Delivered concrete changes in catalog ID management, cursor lifecycle for multi-node comparisons, and drop-pending ident hygiene. The work enhances reliability in disaggregated storage configurations and reduces risk of metadata inconsistencies during createCollection and validation workflows.
July 2025
4 Commits • 1 Features
Jul 1, 2025July 2025 monthly summary for percona/percona-server-mongodb focused on strengthening distributed catalog metadata handling, data consistency, and operational robustness across the server core. Delivered concrete changes in catalog ID management, cursor lifecycle for multi-node comparisons, and drop-pending ident hygiene. The work enhances reliability in disaggregated storage configurations and reduces risk of metadata inconsistencies during createCollection and validation workflows.
June 2025
3 Commits • 1 Features
Jun 1, 2025June 2025 monthly summary for percona/percona-server-mongodb: Delivered targeted fixes and enhancements to oplog-based collection creation and replication fidelity, plus improvements to test utilities. These changes strengthen data consistency during oplog replay, reduce operational risk in replicated deployments, and improve maintainability.
3 Commits • 1 Features
Jun 1, 2025June 2025 monthly summary for percona/percona-server-mongodb: Delivered targeted fixes and enhancements to oplog-based collection creation and replication fidelity, plus improvements to test utilities. These changes strengthen data consistency during oplog replay, reduce operational risk in replicated deployments, and improve maintainability.
June 2025
May 2025
5 Commits • 2 Features
May 1, 2025May 2025 performance review for percona/percona-server-mongodb: Delivered two high-impact changes that strengthen reliability, maintainability, and cross-node consistency in the storage catalog. First, a DurableCatalog internal refactor reorganized the catalog codebase by introducing MDBCatalog and a durable_catalog namespace, relocating catalog-related files, and simplifying index management signatures while aligning RecordStore options. Commits include 4085a07816b9bf106ff7a27cc8183a5ebcba9817; 4cad604863c3b4ae8ce70057c26f0f62e8d43918; 66d4466af38e0dcf90337431a50f98fa053f348d; 14cc97aaf66884fc9e4a742431ecb905672b31ce. Second, introduced a replication consistency feature flag featureFlagReplicateLocalCatalogIdentifiers to enable replication of local catalog identifiers across replica set nodes, ensuring consistent _mdb_catalog and ident mappings. Commit: 135539bb0a153422c37131edda05a1f1bf540f2e. Major bugs fixed: none explicitly listed; however, the refactor reduces defect risk through clearer separation of catalog concerns and streamlined signatures. Overall impact: improved modularity, maintainability, and cross-node consistency, laying groundwork for safer future catalog evolutions and faster feature delivery. Technologies/skills demonstrated: large-scale codebase refactoring, namespace/module organization, feature flag design and rollout, cross-repo collaboration, and thorough commit tracing.
May 2025
5 Commits • 2 Features
May 1, 2025May 2025 performance review for percona/percona-server-mongodb: Delivered two high-impact changes that strengthen reliability, maintainability, and cross-node consistency in the storage catalog. First, a DurableCatalog internal refactor reorganized the catalog codebase by introducing MDBCatalog and a durable_catalog namespace, relocating catalog-related files, and simplifying index management signatures while aligning RecordStore options. Commits include 4085a07816b9bf106ff7a27cc8183a5ebcba9817; 4cad604863c3b4ae8ce70057c26f0f62e8d43918; 66d4466af38e0dcf90337431a50f98fa053f348d; 14cc97aaf66884fc9e4a742431ecb905672b31ce. Second, introduced a replication consistency feature flag featureFlagReplicateLocalCatalogIdentifiers to enable replication of local catalog identifiers across replica set nodes, ensuring consistent _mdb_catalog and ident mappings. Commit: 135539bb0a153422c37131edda05a1f1bf540f2e. Major bugs fixed: none explicitly listed; however, the refactor reduces defect risk through clearer separation of catalog concerns and streamlined signatures. Overall impact: improved modularity, maintainability, and cross-node consistency, laying groundwork for safer future catalog evolutions and faster feature delivery. Technologies/skills demonstrated: large-scale codebase refactoring, namespace/module organization, feature flag design and rollout, cross-repo collaboration, and thorough commit tracing.
April 2025
3 Commits • 1 Features
Apr 1, 2025April 2025: Delivered Storage Engine API and Catalog Improvements for Percona Server MongoDB, consolidating API and catalog changes to improve configuration handling, data integrity, and API clarity across DurableCatalog, record store creation, and storage engine interactions. This work reduces configuration complexity, enforces data integrity, and simplifies record store creation flows across the storage engine.
3 Commits • 1 Features
Apr 1, 2025April 2025: Delivered Storage Engine API and Catalog Improvements for Percona Server MongoDB, consolidating API and catalog changes to improve configuration handling, data integrity, and API clarity across DurableCatalog, record store creation, and storage engine interactions. This work reduces configuration complexity, enforces data integrity, and simplifies record store creation flows across the storage engine.
April 2025
March 2025
5 Commits • 2 Features
Mar 1, 2025March 2025 monthly summary for percona/percona-server-mongodb. Focused on strengthening storage layer consistency, test stability, and maintainability through UUID-based identifier generation, targeted test management, and code cleanup. Key contributions centered on unified ident generation, temporary test management for investigation, and signature simplification to reduce future risks.
March 2025
5 Commits • 2 Features
Mar 1, 2025March 2025 monthly summary for percona/percona-server-mongodb. Focused on strengthening storage layer consistency, test stability, and maintainability through UUID-based identifier generation, targeted test management, and code cleanup. Key contributions centered on unified ident generation, temporary test management for investigation, and signature simplification to reduce future risks.
February 2025
1 Commits • 1 Features
Feb 1, 2025February 2025 monthly summary for percona/percona-server-mongodb: Focused on code quality and maintainability in the indexing path. Delivered a targeted code cleanup that removes a redundant invariant check in createIndexOnEmptyCollection, with no change to behavior. This aligns with ongoing efforts to simplify critical code paths and reduce maintenance burden.
1 Commits • 1 Features
Feb 1, 2025February 2025 monthly summary for percona/percona-server-mongodb: Focused on code quality and maintainability in the indexing path. Delivered a targeted code cleanup that removes a redundant invariant check in createIndexOnEmptyCollection, with no change to behavior. This aligns with ongoing efforts to simplify critical code paths and reduce maintenance burden.
February 2025
January 2025
4 Commits • 1 Features
Jan 1, 2025January 2025 monthly summary for percona/percona-server-mongodb focused on delivering targeted reliability improvements and test stability across Change Streams, TTL index handling, and timeseries tests. Delivered a new lifecycle service for pre-image expiry, simplified TTL index monitoring by removing a fixer, and stabilized timeseries tests to reduce flaky behavior. These changes enhance data correctness, reduce maintenance burden, and improve CI reliability, supporting safer rollbacks and more predictable replica set operations.
January 2025
4 Commits • 1 Features
Jan 1, 2025January 2025 monthly summary for percona/percona-server-mongodb focused on delivering targeted reliability improvements and test stability across Change Streams, TTL index handling, and timeseries tests. Delivered a new lifecycle service for pre-image expiry, simplified TTL index monitoring by removing a fixer, and stabilized timeseries tests to reduce flaky behavior. These changes enhance data correctness, reduce maintenance burden, and improve CI reliability, supporting safer rollbacks and more predictable replica set operations.
November 2024
4 Commits • 2 Features
Nov 1, 2024Month: 2024-11 — Delivered targeted improvements to pre-image handling and codebase hygiene in percona/percona-server-mongodb, with focused test stability work. Business value centers on improved expiration accuracy for pre-images, robust sampling, maintainable code, and more reliable tests for ongoing development.
4 Commits • 2 Features
Nov 1, 2024Month: 2024-11 — Delivered targeted improvements to pre-image handling and codebase hygiene in percona/percona-server-mongodb, with focused test stability work. Business value centers on improved expiration accuracy for pre-images, robust sampling, maintainable code, and more reliable tests for ongoing development.
November 2024
October 2024
1 Commits • 1 Features
Oct 1, 2024Month: 2024-10 — Focused on simplifying the change stream feature set for percona-server-mongodb by removing the deprecated ChangeCollectionTruncateMarkers functionality. This included deleting related configuration, tests, and code, resulting in a cleaner, more maintainable change stream surface and reduced support burden. All changes were reviewed and validated through CI, with no regressions observed in change stream workflows.
October 2024
1 Commits • 1 Features
Oct 1, 2024Month: 2024-10 — Focused on simplifying the change stream feature set for percona-server-mongodb by removing the deprecated ChangeCollectionTruncateMarkers functionality. This included deleting related configuration, tests, and code, resulting in a cleaner, more maintainable change stream surface and reduced support burden. All changes were reviewed and validated through CI, with no regressions observed in change stream workflows.
Activity
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Quality Metrics
Correctness95.8%
Maintainability90.2%
Architecture93.4%
Performance84.0%
AI Usage24.8%
Skills & Technologies
Programming Languages
BazelC++IDLJavaScriptMarkdownYAML
Technical Skills
API DesignBackend DevelopmentBazelBuild System ManagementBuild SystemsC++C++ DevelopmentC++ developmentC++ programmingCI/CDCatalog ManagementChange Data CaptureChange StreamsCode CleanupCode Organization
Repositories Contributed To
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