Slow Site Performance Diagnosis

Diagnosing Slow WordPress Performance

If your BlitzPress site is loading slowly, follow this systematic approach to identify the bottleneck. Performance issues usually fall into caching, database, PHP, or resource categories.

Check LSCache Status

BlitzPress uses LiteSpeed Cache (LSCache) for full-page caching. Verify it is working:

curl -I https://YOUR_DOMAIN/ 2>/dev/null | grep -i x-litespeed

You should see X-LiteSpeed-Cache: hit. If you see miss on every request, the cache is not functioning properly. Check the LiteSpeed Cache plugin settings in WordPress.

Check OPcache

OPcache stores compiled PHP bytecode in memory. Verify it is enabled and has good hit rates:

php -r "print_r(opcache_get_status(false));" | grep -E "hits|misses|memory"

A high miss rate means OPcache is too small. Increase it in your PHP configuration.

Check Redis Object Cache

Verify Redis is connected and serving object cache:

redis-cli ping         # Should return PONG
redis-cli info stats   # Check hit rate

In WordPress, ensure the Redis Object Cache plugin shows “Connected” status.

Enable PHP Slow Log

The PHP slow log records functions that take longer than a threshold:

# In php.ini or pool config
request_slowlog_timeout = 5s
slowlog = /home/YOUR_DOMAIN/logs/php-slow.log

Review the slow log to find which PHP functions are bottlenecks.

Check MySQL Slow Queries

sudo mysql -e "SHOW VARIABLES LIKE 'slow_query_log%';"
sudo mysql -e "SHOW VARIABLES LIKE 'long_query_time';"

Enable and review slow queries to find database bottlenecks. See the MySQL Slow Query Log article for details.

Server Resource Check

top -bn1 | head -20           # CPU and memory overview
df -h                          # Disk space
iostat -x 1 3                  # Disk I/O
ss -tlnp | grep -E "80|443"   # Connection counts

Quick Performance Checklist

• LSCache plugin installed and enabled with proper cache rules
• Redis object cache connected and active
• OPcache enabled with sufficient memory (128MB+)
• No resource-heavy plugins (broken link checkers, real-time analytics)
• Images optimized (use ShortPixel or Imagify)
• Database optimized (clean transients and revisions)