Month: 2025-10 Key features delivered: - Transaction management enhancements for indirect transactions (sync and async) in iTwin/itwinjs-core: support for nested indirect calls via a reference counter; direct mode is now set only after all indirect calls complete; added withIndirectTxnModeAsync for asynchronous indirect transactions. - Expanded test coverage for EDE graph operations, topological sorting, and cycle detection to validate correctness under concurrent/workflow scenarios. Major bugs fixed: - iTwin/imodel-native: ECSqlReader concurrent queries do not observe latest file state; fix uses file data versioning and cache invalidation to ensure latest state is visible during concurrent queries. - iTwin/imodel-native: Crash on cycles in EDE change propagation; introduce dedicated error code and have the transaction manager return it instead of abort, boosting robustness. - iTwin/itwinjs-core: ECSqlReader not seeing modifications after saveChanges; fixes visibility after insert/save and added tests simulating concurrent queries. - iTwin/itwinjs-core: Crash in EDE change propagation on cycle detection; add new error codes for propagation failures and not-open states; update saveChanges handling; comprehensive tests for topological sorting, cycle detection, and EDE graph operations. Overall impact and accomplishments: - Significantly improved data consistency for concurrent ECSqlReader queries by ensuring modifications are visible, reducing data staleness in multi-threaded scenarios. - Increased robustness of change propagation by safely handling cycles and returning explicit error codes, minimizing crashes and rollback risks. - Safer and more deterministic indirect transaction management, reducing risky operations during rebasing and nested calls. - Expanded test coverage validated against realistic concurrent/workflow scenarios, boosting confidence for future changes. Technologies/skills demonstrated: - Concurrency control, cache invalidation, and data versioning in ECSqlReader paths. - Graph algorithms for EDE: cycle detection and topological sorting. - Transaction management: nested indirect transactions, indirect mode lifecycle, and async support. - Error-code design and test-driven validation of propagation and saveChanges workflows.

September 2025: Delivered critical database modernization and safer multi-user collaboration enhancements across iTwin-native and itwinjs-core. Upgraded embedded SQLite to 3.50.4 with changeset fixes and introduced in-memory changeset APIs; strengthened multi-user pull-merge/rebase workflows with improved transaction management and data integrity; added restore-point and stash management for safer merges; enabled in-memory reading of unsaved changes. These changes improve reliability, security conformity, and developer productivity, accelerating collaborative workflows and reducing risk during complex merges.

August 2025: Delivered critical schema management improvements across core SDKs with a focus on cross-client consistency and test reliability. Implemented a multi-user Schema Dropping Synchronization Validation Test in iTwinJS Core to validate that dropping a schema on one client is reflected in others after pull, preventing access to dropped schema classes. Enhanced iModel Native Schema Remap Tests with refactored test structure, updated XML schemas to include new properties/classes, and adjusted import options for schema upgrades, boosting test robustness and accuracy. Overall impact: increased confidence in schema evolution workflows, reduced risk of post-release regressions, and better alignment between client and server schema states. Technologies/skills: C++, test frameworks, XML schema modeling, multi-repo test orchestration, and CI-ready test design.

July 2025: Focused on correctness and test coverage for the pullChange workflow in iTwinJS core. Delivered a bug fix that prevents unintended pending transactions when there are no local modifications, and added a simulated multi-user test to validate proper behavior, leading to more reliable synchronization across clients. This reduces reconciliation complexity and improves data integrity in multi-user scenarios.

June 2025 performance highlights across iTwin/imodel-native and iTwin/itwinjs-core. Delivered core features, robust build fixes, and data-integrity improvements that accelerate development velocity, reduce downstream risks, and enable scalable handling of large changesets. The work demonstrates strong cross‑repo collaboration, API modernization, and platform-specific reliability improvements that directly impact product stability, developer experience, and customer value.

Concise monthly developer summary for May 2025 across iTwin/imodel-native and iTwin/itwinjs-core focused on high-value features, stability fixes, and technical excellence reflected in code quality, tests, and performance improvements.

In April 2025, the iTwin/imodel-native team focused on improving the robustness of ECDb schema evolution and expanding the ECDb API surface, delivering changes with clear business value and strong technical merit. The work enhances upgrade stability, enables more efficient data handling, and lays groundwork for TS-driven logic integration.

March 2025: Implemented cross-database attachment capabilities for IModelDb across two repos to enable multi-database querying. In iTwin/imodel-native, added attach/detach databases support with new management methods, concurrency synchronization for query managers, and a PRAGMA to list attached databases (commit 56621b98a5b6254f8a3ba5b65814d5e9b605c41b). In iTwin/itwinjs-core, added external database attachment support to IModelDb, exposing new methods on ECDb and IModelDb and adding tests (commit bf6ba49da3964a5b75cc7624442614926534e102). Business value: enables integrated analytics across multiple databases, simplifies data access patterns, and reduces operational overhead for multi-database scenarios. Technical impact: new APIs, tests, synchronization logic, and cross-repo collaboration.

February 2025 monthly summary for iTwin/itwinjs-core: Delivered a critical bug fix to robustly handle interrupted queries during preparation and shutdown, improving reliability of query processing and error handling. Enhanced statistics collection for query execution, including preparation time, enabling better performance visibility and capacity planning. Added testing arguments to validate interruption scenarios, increasing resilience and test coverage. Commit reference f5485d71394f8ce6de37fe0ad953584ddd8223e7 (#7592).

January 2025 focused on strengthening pull/merge workflows with robust rebase strategies, improving query performance and stability, and upgrading core IO/DB subsystems to support higher throughput and reliability. The work spans iTwin/imodel-native and iTwin/itwinjs-core, delivering consistent enhancements for conflict handling, thread-safety, and performance optimizations.

Month: 2024-12 | Focused on stabilizing CI and improving test reliability in iTwin/itwinjs-core. Delivered a targeted change to disable a flaky MergeConflict.test.ts, preventing intermittent CI/CD failures and unreliable test reports. This work reduces noise in CI dashboards, accelerates triage, and strengthens release readiness.

November 2024 monthly summary focusing on delivering upgrade-ready database capabilities, robust schema migration tooling, and reliability improvements across two repos. The work prioritized business value: safer upgrade paths, stronger data integrity during migrations, and reduced operational risk in production deployments for iTwin/imodel-native and iTwinjs-core.