Advanced WordPress Development

Chapter 9: Performance Optimization

9.1 Caching Strategies

Implement caching to improve performance.

• Page Caching: Cache full page output
• Object Caching: Cache database queries
• Browser Caching: Cache static assets
• CDN: Content Delivery Network

9.2 Database Query Optimization

Optimize database queries for better performance.

// Use transients for expensive queries
$data = get_transient('expensive_query');

if (false === $data) {
    $data = expensive_database_query();
    set_transient('expensive_query', $data, HOUR_IN_SECONDS);
}

9.3 Image Optimization

Optimize images for web performance.

• Use appropriate image formats (WebP, JPEG, PNG)
• Compress images before upload
• Use responsive images (srcset)
• Lazy load images
• Use image CDN

9.4 Script and Style Optimization

Optimize JavaScript and CSS loading.

// Defer JavaScript
wp_enqueue_script('script', 'url', array(), '1.0', true);

// Minify CSS/JS
wp_enqueue_style('style', 'url', array(), '1.0', 'all');

// Remove unused scripts
wp_dequeue_script('unused-script');

9.5 Performance Monitoring

Monitor and measure site performance.

• Use tools like GTmetrix, PageSpeed Insights
• Monitor Core Web Vitals
• Use Query Monitor plugin
• Monitor server resources
• Track page load times