Common performance issues

# Misconfiguration

Configuration errors are among the most common causes of performance issues—development settings in production, improper caching, or conflicting plugins can bottleneck a live app. These problems often go unnoticed during testing but surface immediately when deployed with real traffic and data volumes.

• All assets are re-generated with each deployment or even page load — see cached directories to preserve vendor folders across deploys
• The production environment is set to development
• A plugin creates a ton of load or conflicts with other config
• Slow MySQL queries — see database performance tips

# External sources

Applications depend on external APIs, CDNs, payment processors, and third-party services; when these fail or slow down, your app's performance suffers immediately. A single slow external service can create cascading delays throughout your application.

• A third party service is down or slow

# Data threshold reached

Apps that perform well with test data can hit performance walls with real-world data volumes. Queries fast with hundreds of records become slow with thousands—a common source of surprise performance degradation in production.

• A MySQL query that is fast locally with little testing data, is slow in production

# Usage patterns changed

Visitor traffic and bot activity patterns change over time; spikes, new workflows, or aggressive crawling can expose performance bottlenecks that weren't visible under normal conditions.

• A website was linked from a popular blog and gets more visits
• A new user is uploading images of a larger size
• Bots are aggressively curling all pages