performance

Domain 3: Performance Analysis

3.1 Database Performance

• Identify N+1 query patterns (queries inside loops)
• Flag meta_query without proper indexing
• Detect unnecessary LIKE '%value%' queries (leading wildcard prevents index use)
• Check for missing indexes on custom tables
• Identify excessive wp_options autoloading (total autoloaded data size)
• Review transient usage — orphaned or never-expiring transients
• Detect SELECT * where specific columns would suffice
• Flag ORDER BY RAND() on large datasets
• Check post revision accumulation and recommend limits
• Review wp_postmeta table bloat

3.2 PHP Performance

• Identify expensive operations in init, wp_loaded, or admin_init hooks that should run conditionally
• Detect heavy computation on every page load vs lazy/on-demand execution
• Flag blocking HTTP API calls without timeouts
• Identify missing object caching for repeated expensive operations
• Check for excessive use of get_option() on non-autoloaded options (each triggers a DB query)
• Detect memory-intensive operations (loading all posts, large arrays in memory)
• Review cron jobs for efficiency and proper scheduling
• Identify duplicate plugin functionality (multiple SEO plugins, multiple caching layers)

3.3 Frontend Performance

• Audit render-blocking CSS and JavaScript
• Check proper use of wp_enqueue_script() / wp_enqueue_style() (not hardcoded in templates)
• Verify scripts load in footer where possible (in_footer parameter)
• Identify scripts/styles loaded globally that should be conditional
• Check for proper async/defer attributes
• Review image optimization (WebP support, proper sizing, lazy loading)
• Identify excessive DOM size from page builder bloat
• Check for unused CSS/JS being loaded
• Verify proper use of WordPress asset dependency system
• Core Web Vitals impact assessment (LCP, FID/INP, CLS)

3.4 Caching Analysis

• Page caching configuration and effectiveness
• Object caching (Redis/Memcached) configuration
• Browser caching headers (Cache-Control, Expires, ETag)
• CDN configuration and cache hit rates
• Fragment caching for dynamic content areas
• Transient API usage patterns
• OPcache configuration for PHP

Tool Usage: Performance Analysis Commands

Database Analysis

# Analyze autoloaded options size
wp db query "SELECT option_name, LENGTH(option_value) as size FROM wp_options WHERE autoload='yes' ORDER BY size DESC LIMIT 20;"

# Count orphaned transients
wp db query "SELECT COUNT(*) FROM wp_postmeta WHERE meta_key LIKE '_transient_%';"

# Count post revisions
wp db query "SELECT COUNT(*) FROM wp_posts WHERE post_type='revision';"

# Analyze wp_postmeta table size
wp db query "SELECT COUNT(*) as total_rows, SUM(LENGTH(meta_value)) as total_size FROM wp_postmeta;"

# Find slow queries (requires query log enabled)
wp db query "SELECT * FROM mysql.slow_log ORDER BY query_time DESC LIMIT 10;"

WordPress CLI Diagnostics

# Database optimization
wp db optimize
wp db repair

# Transient cleanup
wp transient delete --expired
wp transient delete --all

# Cron inspection
wp cron event list
wp cron schedule list

# Cache management
wp cache flush
wp cache type  # Show cache type (Redis, Memcached, etc.)

Query Monitoring

# Enable Query Monitor plugin for development
wp plugin install query-monitor --activate

# Check for slow queries in debug log
tail -f /path/to/wp-content/debug.log | grep "Slow query"