I diagnose and improve PostgreSQL databases used by production applications. The work can include slow-query analysis, EXPLAIN plan review, indexing strategy, schema and data-model improvements, connection and transaction tuning, API bottleneck tracing, migrations and reproducible benchmarks. I also work across C#/.NET, Python and Flutter backends, so I can follow performance problems beyond SQL into application code and infrastructure. You receive focused, tested changes, clear before/after measurements and practical documentation for future maintenance.