performance-optimization

name	performance-optimization
description	Drupal performance optimization guide covering Redis, caching, database optimization, and asset management.

Performance Optimization Skill

Comprehensive guide for optimizing Drupal performance.

Stack Overview

Component	Technology	Purpose
Database	PostgreSQL or MySQL/MariaDB	Primary data store
Cache	Redis (or Memcached)	Object/session cache
Search	Apache Solr (or Elasticsearch)	Full-text search
Web Server	Apache or Nginx	HTTP serving
PHP	8.2+	Application runtime

Quick Diagnostics

# Overall health
./vendor/bin/drush core:status

# Cache status
./vendor/bin/drush cache:list

# Redis stats
redis-cli INFO memory | grep used_memory_human
redis-cli INFO stats | grep -E "keyspace_hits|keyspace_misses"

# Database size (PostgreSQL)
./vendor/bin/drush sql:query "SELECT pg_size_pretty(pg_database_size(current_database()))"

# Database size (MySQL)
./vendor/bin/drush sql:query "SELECT table_schema AS db, ROUND(SUM(data_length + index_length) / 1024 / 1024, 2) AS 'Size (MB)' FROM information_schema.tables WHERE table_schema = DATABASE() GROUP BY table_schema"

---

1. Redis Caching

Configuration Location

sites/default/settings.redis.php (or inline in settings.php)

Recommended Settings

// Enable Redis
$settings['redis.connection']['interface'] = 'PhpRedis';
$settings['redis.connection']['host'] = '127.0.0.1';
$settings['redis.connection']['port'] = '6379';

// Cache bins to use Redis
$settings['cache']['default'] = 'cache.backend.redis';

// High-value cache bins
$settings['cache']['bins']['render'] = 'cache.backend.redis';
$settings['cache']['bins']['dynamic_page_cache'] = 'cache.backend.redis';
$settings['cache']['bins']['page'] = 'cache.backend.redis';
$settings['cache']['bins']['bootstrap'] = 'cache.backend.redis';
$settings['cache']['bins']['config'] = 'cache.backend.redis';
$settings['cache']['bins']['discovery'] = 'cache.backend.redis';

// Keep some bins in database (rarely accessed)
$settings['cache']['bins']['migrate'] = 'cache.backend.database';

Redis Memory Optimization

# Check memory
redis-cli INFO memory

# Set max memory (in redis.conf)
# maxmemory 512mb
# maxmemory-policy allkeys-lru

# Monitor real-time
redis-cli MONITOR

# Clear Redis cache
redis-cli FLUSHDB

Hit Rate Analysis

redis-cli INFO stats | grep -E "keyspace_hits|keyspace_misses"
# Calculate: hits / (hits + misses) * 100 = hit rate %
# Target: > 90%

---

2. Drupal Caching Layers

Cache Hierarchy

1. Page Cache - Full page for anonymous users
2. Dynamic Page Cache - Partial pages for authenticated users
3. Render Cache - Individual render elements
4. Internal Cache - Discovery, config, bootstrap

Views Caching

# In views configuration
display:
  cache:
    type: tag  # Invalidates on content change
    # OR
    type: time
    options:
      results_lifespan: 3600   # 1 hour
      output_lifespan: 3600

# For static content
display:
  cache:
    type: time
    options:
      results_lifespan: 86400  # 24 hours
      output_lifespan: 86400

Block Caching

// In Block plugin
public function getCacheMaxAge() {
  return 3600; // 1 hour
}

public function getCacheContexts() {
  return ['user.roles', 'url.path'];
}

public function getCacheTags() {
  return ['node_list:article'];
}

BigPipe

# Enable BigPipe for better perceived performance
./vendor/bin/drush en big_pipe -y

---

3. Database Optimization

PostgreSQL Tuning

-- Check slow queries (requires pg_stat_statements)
SELECT query, calls, total_time, mean_time
FROM pg_stat_statements
ORDER BY total_time DESC
LIMIT 10;

-- Table sizes
SELECT relname, pg_size_pretty(pg_total_relation_size(relid))
FROM pg_catalog.pg_statio_user_tables
ORDER BY pg_total_relation_size(relid) DESC
LIMIT 20;

-- Index usage
SELECT indexrelname, idx_scan, idx_tup_read, idx_tup_fetch
FROM pg_stat_user_indexes
ORDER BY idx_scan DESC;

-- Unused indexes
SELECT indexrelname, idx_scan
FROM pg_stat_user_indexes
WHERE idx_scan = 0;

-- Vacuum and analyze
VACUUM ANALYZE;

MySQL/MariaDB Tuning

-- Check slow queries (enable slow_query_log in my.cnf)
-- slow_query_log = 1
-- long_query_time = 2

-- Table sizes
SELECT table_name,
       ROUND(((data_length + index_length) / 1024 / 1024), 2) AS 'Size (MB)'
FROM information_schema.tables
WHERE table_schema = DATABASE()
ORDER BY (data_length + index_length) DESC
LIMIT 20;

-- Index usage
SELECT * FROM sys.schema_unused_indexes
WHERE object_schema = DATABASE();

-- Check for missing indexes
SELECT * FROM sys.statements_with_full_table_scans
WHERE db = DATABASE()
ORDER BY no_index_used_count DESC
LIMIT 10;

-- Optimize tables
OPTIMIZE TABLE cache_default, cache_render, cache_page;

Query Optimization

// BAD: N+1 queries
foreach ($nids as $nid) {
  $node = Node::load($nid);
}

// GOOD: Batch loading
$nodes = Node::loadMultiple($nids);

// BAD: Load all fields
$nodes = $storage->loadMultiple($nids);

// GOOD: Only load needed data
$query = $storage->getQuery()
  ->condition('type', 'article')
  ->condition('status', 1)
  ->range(0, 50);
$nids = $query->execute();

Entity Query Best Practices

// Use accessCheck appropriately
$query = \Drupal::entityQuery('node')
  ->accessCheck(TRUE)  // Required in Drupal 10+
  ->condition('type', 'article')
  ->condition('status', 1)
  ->sort('created', 'DESC')
  ->range(0, 10);

// Add caching tags
$nodes = Node::loadMultiple($query->execute());
$build['#cache']['tags'] = Cache::mergeTags(
  $build['#cache']['tags'] ?? [],
  ['node_list:article']
);

---

4. Asset Optimization

CSS/JS Aggregation

// settings.php (production)
$config['system.performance']['css']['preprocess'] = TRUE;
$config['system.performance']['js']['preprocess'] = TRUE;

Image Optimization

# responsive_image.style.*.yml
responsive_image_style:
  id: wide
  breakpoints:
    - media: '(min-width: 1200px)'
      image_style: wide_desktop
    - media: '(min-width: 768px)'
      image_style: wide_tablet
    - media: ''
      image_style: wide_mobile

Lazy Loading

{# In templates #}
<img loading="lazy" src="{{ image_url }}" alt="{{ alt }}">

{# Or via preprocess #}
$variables['attributes']['loading'] = 'lazy';

---

5. Common Performance Issues

Issue: Slow Views

Diagnosis:

./vendor/bin/drush views:analyze

Solutions:

1. Add caching to view display
2. Reduce fields to minimum needed
3. Add appropriate filters
4. Use pager or limit results
5. Consider using Search API instead

Issue: Heavy Preprocess Functions

Diagnosis:

grep -r "entityTypeManager\|database" themes/custom/*/\*.theme

Solutions:

1. Move logic to services
2. Cache expensive computations
3. Use lazy builders

Issue: Too Many Modules

Diagnosis:

./vendor/bin/drush pm:list --status=enabled | wc -l

Solutions:

1. Disable unused modules
2. Combine functionality
3. Use lazy loading where possible

Issue: Large Sessions

Diagnosis:

redis-cli --scan --pattern '*session*' | head -10

Solutions:

1. Reduce session data
2. Clean old sessions
3. Use Redis for sessions

---

6. Monitoring & Profiling

Built-in Tools

# Enable performance logging
./vendor/bin/drush config:set system.logging error_level verbose -y

# Check recent slow pages
./vendor/bin/drush watchdog:show --severity=warning

Database Query Logging

// settings.local.php (development only)
$settings['container_yamls'][] = DRUPAL_ROOT . '/sites/development.services.yml';
$config['system.logging']['error_level'] = 'verbose';

Memory Profiling

# PHP memory
php -i | grep memory_limit

# Drupal memory usage
./vendor/bin/drush php:eval "echo 'Memory: ' . round(memory_get_peak_usage() / 1024 / 1024, 2) . 'MB';"

---

7. Performance Checklist

Before Deployment

• CSS/JS aggregation enabled
• Page cache enabled for anonymous
• Views have appropriate caching
• Images use responsive styles
• Redis (or Memcached) configured and working
• No development modules enabled
• Error logging set to production level

Regular Maintenance

• Clear stale cache entries
• Prune old revisions
• Clean watchdog logs
• Run database maintenance (VACUUM for PostgreSQL, OPTIMIZE for MySQL)
• Check Redis memory usage
• Review slow query log

Commands

# Full cache clear
./vendor/bin/drush cr

# Rebuild only specific cache
./vendor/bin/drush cache:rebuild router

# Database maintenance (PostgreSQL)
./vendor/bin/drush sql:query "VACUUM ANALYZE"

# Database maintenance (MySQL)
# Run OPTIMIZE TABLE on large cache/log tables via drush sql:cli

# Clear old logs
./vendor/bin/drush watchdog:delete all