Free, open-source SQL Server performance monitoring and diagnostics

Performance Monitor for SQL Server is a WPF desktop application that collects and visualizes SQL Server performance data including wait stats, query plans, deadlocks, blocking, index usage, and more. It comes in two editions: a Full Edition with server-side collection into a central database, and a standalone Lite Edition using embedded DuckDB. Both include a built-in MCP server for AI-assisted diagnostics.