Performance Anti-Patterns for Code Review

Overview

Performance anti-patterns are recurring mistakes that degrade throughput, latency, or resource efficiency. They often go undetected in development and surface only under production load. This catalog focuses on signals a reviewer can spot in a PR diff.

Use alongside anti-patterns-catalog (structural problems) and review-code-quality-process (review workflow).

When to Use

• PR touches database queries, HTTP clients, or any I/O layer
• p95 latency or memory usage increased without obvious cause
• Load testing shows non-linear scaling
• PR introduces loops, recursion, or collection transforms
• PR modifies caching logic or connection management

Quick Reference