QueryDiff

QueryDiff is a web app + CLI that automatically detects SQL query performance regressions across schema changes, ORM upgrades, and data growth. You point it at a staging database (Postgres/MySQL to start), and it runs a repeatable benchmark suite: your top queries from logs, plus a curated set of synthetic workloads. It snapshots EXPLAIN plans, key stats (rows, buffers, temp spills), and latency distributions, then compares builds as a “performance diff” with clear blame signals (index dropped, cardinality shift, plan flip). It’s not a full APM replacement; it’s a focused gate in CI/CD for database performance. Teams get a simple pass/fail threshold, a report link for code review, and a short list of recommended indexes or query rewrites. The goal is fewer surprise slowdowns after migrations—without hiring a dedicated DBA.