Introduction
Performance issues rarely announce themselves with obvious errors. More often, they appear as subtle increases in latency that gradually worsen as data volume grows.
While working on a Node.js and PostgreSQL application, I noticed a user-facing API endpoint consistently taking approximately 2.8 seconds to respond. The endpoint was functionally correct, but its performance was unacceptable for production use.
This article walks through the investigation process, root cause analysis, optimization strategy, and the changes that reduced response time to 74 milliseconds.
The Problem
