January 2026 performance monthly summary for paradedb/paradedb. Key feature delivered: TopN Scan usage diagnostic through a new GUC paradedb.check_topn_scan that warns when a LIMIT query should use TopN scan but falls back to a slower execution method, enabling early detection of performance regressions in production. Implementation includes changes to the TopN validation logic and integration with the query planner. Tests added to validate behavior under multiple scenarios. Major bugs fixed: None reported in this scope. Impact and accomplishments: Improves production performance visibility for LIMIT queries by surfacing missed TopN optimizations, reducing latency in critical paths, and enabling targeted remediation. The feature helps prevent 100–1000x slowdowns observed in production when TopN optimizations are not applied. It also enhances observability and operator confidence through explicit warnings and tests. Technologies/skills demonstrated: Rust (GUCs and custom scan logic), Postgres extension development (TopN validation, choose_exec_method integration), performance testing and regression testing (pg_regress tests), code maintenance and documentation for production readiness.