The Complete Guide to WordPress Multisite Database Management
Understanding WordPress Multisite Database Architecture
WordPress Multisite’s database structure differs significantly from standard WordPress installations. Where single sites use one set of tables, Multisite introduces:
- Shared tables (network-wide settings)
- Per-site tables (individual site content)
- Global vs local data separation
Key Multisite Database Tables
| Table Type | Example Tables | Purpose |
|---|---|---|
| Network Core | wp_blogs, wp_site, wp_sitemeta | Stores network structure and settings |
| Shared Content | wp_users, wp_usermeta | Centralized user management |
| Site-Specific | wp_2_posts, wp_3_options | Individual site data (prefix = blog ID) |
Essential Multisite Database Management Techniques
1. Optimizing Multisite Database Performance
a. Table Indexing Strategy
-- Add index to frequently queried columns ALTER TABLE wp_blogs ADD INDEX (domain(50), path(50));
b. Cache Configuration
Enable persistent object caching (Redis/Memcached). Our YouTube channel; https://www.youtube.com/@easythemestore
Configure
wp-config.php:define('WP_CACHE', true); define('WP_REDIS_HOST', '127.0.0.1');
c. Automated Maintenance
# Add to cron (weekly) wp db optimize --network wp db repair --network
2. Managing Large-Scale Multisite Migrations
a. Exporting Specific Sites
# Export site ID 5 while preserving table prefixes wp db export --tables=wp_5_* --result-file=single-site-export.sql
b. Merging Multiple Single Sites into Multisite
Use the Mergebot plugin for conflict-free merging
Manual process:
// In wp-config.php before migration define('WP_ALLOW_MULTISITE', true);
3. Advanced Querying Across Multiple Sites
a. Network-Wide User Search
SELECT * FROM wp_users u JOIN wp_usermeta um ON u.ID = um.user_id WHERE um.meta_key = 'first_name' AND um.meta_value LIKE '%John%';
b. Find Duplicate Content Across Sites
SELECT p1.post_title, p1.guid, b1.domain FROM wp_2_posts p1 INNER JOIN wp_3_posts p2 ON p1.post_content = p2.post_content JOIN wp_blogs b1 ON p1.blog_id = b1.blog_id;
Security Hardening for Multisite Databases
1. Table Encryption
-- Encrypt sensitive user data ALTER TABLE wp_usermeta MODIFY COLUMN meta_value VARBINARY(255) ENCRYPTED=YES;
2. Permission Isolation
// wp-config.php addition define('DB_HOST', 'localhost:/tmp/mysql.sock'); define('DB_USER', 'multisite_limited_user'); // Grant only SELECT, INSERT, UPDATE, DELETE
Troubleshooting Common Multisite Database Issues
Problem: “Table doesn’t exist” errors after site creation
Solution:
// Run network repair define('WP_ALLOW_REPAIR', true); // Visit: /wp-admin/maint/repair.php
Problem: Slow network admin dashboard
Fix:
-- Optimize the sitemeta table OPTIMIZE TABLE wp_sitemeta;
Multisite Database Scaling Strategies
| Approach | When to Use | Implementation |
|---|---|---|
| Sharding | 100+ sites | Assign sites to different database servers |
| Read Replicas | High-traffic networks | Configure in wp-config.php |
| Table Partitioning | Large user tables | Split wp_usermeta by user_id ranges |
Essential Plugins for Multisite DB Management
- WP Sync DB Multisite – Handles cross-site migrations
- Network Shared Media – Centralizes media library
- Multisite Clone Duplicator – Site template system
Backup Strategy for Multisite
#!/bin/bash # Network-wide backup script DATE=$(date +%Y-%m-%d) mysqldump --single-transaction --quick \ --ignore-table=wp_*.wp_options \ --ignore-table=wp_*.wp_postmeta \ --databases wp_multisite > full-backup-$DATE.sql
This comprehensive approach ensures your Multisite database remains secure, optimized, and scalable as your network grows. Regular maintenance combined with proper architecture planning prevents 90% of common Multisite database issues.