February 2026 performance summary across OpenSearch and Lucene. Key focus: reliability, modernization, and maintainability with tangible business value realized through improved test stability and a cleaner API surface. Key features delivered: - OpenSearch: Flaky tests fixed to improve parallel execution reliability by refactoring test setup to remove shared index creation and moving index creation into individual tests, enabling safe parallel CI runs. Commit 76c7b66bf7fba7691e76efd1c5e415b1993ffd73. - Lucene: API modernization implemented via deprecations and removal of legacy Automaton operations to encourage faster, modern usage and better performance. Commits include removal of deprecated RegExp complement syntax (b18af560da6e954cde6b9e673ee5d2dd0e32cb6a), removal of Operations.concatenate and Operations.union (94b01922a54bf1186f1b910c6b3920950ab0ca64), deprecation of Operations.minus() with testing utility replacement (e1d9149c1ce4dfe25e7556550e33e6359ed9c68c), and deprecation of Operations.complement() (cf3545b71cb4f9ad597c3608cf0f6fd8e52f69f7). Major bugs fixed: - Flaky tests in OpenSearch core tests addressed, reducing CI noise and improving reliability in parallel test execution. Overall impact and accomplishments: - Significantly improved CI stability and test throughput through reliable parallel test execution. - Modernized core APIs in Lucene, enabling faster migrations and reduced maintenance burden for downstream users. - Strengthened cross-repo collaboration by aligning changes with migration guidance and test utilities. Technologies/skills demonstrated: - Test refactoring for parallel environments, CI reliability improvements, and resource isolation. - API modernization, deprecation strategy, and migration planning. - Cross-repo coordination between OpenSearch and Lucene teams; maintained clear commit history and documentation alignment.