Scaling Dynamic
WordPress Websites
WordCamp US Dec. 5th, 2015

Who am I?
Aaron Edwards
@UglyRobotDev
https://profiles.wordpress.org/uglyrobot
, , and CAMPUSPRESS
• CTO of Incsub
• WordPress developer
since 2.6, specializing in
Multisite
• Creator of lots of plugins
and services

One size doesn’t fit all
• Most caching plugins and performance talks
focus on Full Page Caching
• Does nothing for dynamic websites!
Membership Sites
WordPress Multisite

Page Generation Time (ms)
0 100 200 300 400 500 600
29ms200ms300ms
PHP Database Web External
Google Pagespeed recommends 200ms max!
Page Generation Time

Database Optimization
• Limit and optimize queries
• https://wordpress.org/plugins/query-monitor/
• Optimize MySQL config
• Query cache
• MySQLTuner
• Convert high-write tables to InnoDB
• Switch to MariaDB (10-20%) or AWS Aurora (2-3x)
or keep the queries from ever getting to your DB…

Disk
Memory
WordPress Object Cache

Object Caching Plugins
• Memcached - Recommended
• http://wordpress.org/extend/plugins/memcached/ or W3TC
• Redis - Recommended
• https://wordpress.org/plugins/redis-cache/
• APC
• https://wordpress.org/plugins/apc/ or W3TC
• File Based - not recommended
wp-content/object-cache.php

PHP Optimization: Code Profiling
• Beginners: P3 (Plugin Performance Profiler)
• https://wordpress.org/plugins/p3-profiler/
• Advanced: Xdebug + (web/win/k)cachegrind
• Easiest way is the VVV local development
environment
• On Production:

PHP Optimization: Worst Offenders
1. Unnecessary/unoptimized queries
1. Use wp_cache_* functions (object cache required)
2. Per-pageload database writes (stats, redirection, logging
plugins)
2. Watch out for remote requests!
1. Use low timeouts
2. Cache as long as possible, not in transients
3. Flushing rewrite rules poorly
4. Direct filesystem access

Speeding Up PHP
• Use NGINX instead of Apache
• In Multisite use a CDN or Varnish
• Move Session storage to RAM
• Upgrade PHP to 5.5 or 5.6
• Enable and configure OPcache
• Make sure code base fits in cache size:
• opcache.memory_consumption
• opcache.max_accelerated_files
• Increase revalidation frequency:
• opcache.revalidate_freq

Switch to HHVM or PHP7!
http://talks.php.net/fluent15#/wpbench

App Monitoring at Scale
StatsD + StatsD
WordPress Client +
Grafana
https://github.com/etsy/statsd
https://wordpress.org/plugins/statsd/
http://grafana.org/
•Live application
profiling

Too technical for you?
• Hire an experienced SysAdmin
• Use a cutting-edge managed WordPress host

Thank you #WCUS!
@UglyRobotDev
Drag&drop site building, 100+ WordPress plugins and 24/7 expert
WordPress support