queryd - slow query detection for Node.js

Catching database performance regressions before they reach users requires both visibility into query execution and the discipline to enforce latency budgets. Queryd addresses this gap by instrumenting SQL queries in Node.js applications with measurable performance guardrails. The tool wraps database clients at multiple levels—supporting postgres.js tagged templates, raw query functions, or Prisma—to intercept queries and measure their execution time against configurable thresholds.

The product solves a real pain point for teams building latency-sensitive applications. Query performance degrades gradually, and without systematic detection, slow queries often go unnoticed until they cause visible impact. Queryd brings three mechanisms to prevent this: per-query latency thresholds that flag individual slow queries, per-request query budgets that set cumulative limits on database work within a single user request, and sampling controls that keep observability costs minimal in production.

What distinguishes queryd is its pragmatic design philosophy. Rather than requiring a complete database abstraction or architectural restructuring, it integrates at the query execution layer across multiple driver APIs. The sampling-first approach acknowledges that continuous monitoring of all queries in high-traffic applications becomes prohibitively expensive; instead, teams can set sampling rates to stay within their observability budget while still surfacing meaningful regressions. Optional EXPLAIN ANALYZE integration allows deeper investigation of offending queries when needed, shifting between cheap signal and expensive detail.

The implementation provides useful context awareness through request-scoped budgets—tracking not just individual query times but also cumulative query volume and duration within a single request. This catches a different class of performance issues: endpoints that perform many quick queries instead of fewer optimized ones. The configurable sink architecture suggests thoughtful extensibility, allowing teams to route alerts to their existing monitoring systems rather than forcing a new workflow.

As an early-stage open-source project, queryd makes a modest but useful contribution to the Node.js observability ecosystem. It fills a specific niche—SQL query latency monitoring with minimal overhead—without attempting to be a comprehensive database performance platform. Teams already running SQL databases in production and concerned with query regressions will find the tool immediately applicable to their latency budgeting workflow.