Performance

Caching layers

Browser cache (Cloudflare TTLs)
  → Cloudflare edge cache (static assets + cached HTML)
    → Nginx FastCGI cache (full-page HTML, 1h TTL)
      → Redis object cache (DB query results, 1h TTL)
        → MySQL (last resort)

Nginx FastCGI cache

Full-page HTML is cached at the Nginx level. Cache is bypassed for:

• Logged-in users (wordpress_logged_in_* cookie present)
• Cart / checkout pages
• POST requests

To purge the Nginx cache manually:

# SSH into the server
sudo nginx -s reload        # soft reload (keeps connections)
sudo rm -rf /var/cache/nginx/ENV_NAME/*   # nuke full-page cache

Redis object cache

WordPress object cache is backed by Redis via wp-redis. This caches wp_cache_get/set calls — database query results, transients, etc.

wp cache flush   # flush Redis object cache (safe to run anytime)

Cloudflare

• Static assets (JS, CSS, images): Cache Everything rule, 30-day TTL
• HTML pages: Cache Level: Standard, respects Cache-Control headers from Nginx
• Image optimisation: Polish enabled (lossless for PNG, lossy for JPEG)
• Minification: handled by the build pipeline, not Cloudflare

What to avoid

• Avoid wp_query inside loops — each creates a new DB query. Use get_posts() with a transient wrapper.
• Avoid autoloaded options — don’t add large data to wp_options with autoload=yes. Check autoload size: wp eval 'echo size_format(strlen(serialize(wp_load_alloptions())));'
• Avoid uncached external HTTP calls — wrap wp_remote_get() calls in a transient with a reasonable TTL.
• Don’t flush cache on every save — scope clean_post_cache() to the affected post, not site-wide.