Connection timeout error
Check host, port, username, password, and database name configuration. Verify database server is running.
Tip: Try connecting using mysqladmin ping or PostgreSQL's psql to test connectivity.
🔌 Connection Problems
Access denied for user
Verify database credentials are correct. Check user permissions in the database management system.
# MySQL check
mysql -u your_username -p
PDOException: could not find driver
Enable the required PDO extension in php.ini for your database type (e.g., extension=pdo_mysql).
Try running php -m | grep pdo to verify driver is loaded.
� Display Problems
No database tables shown
Ensure you've selected the correct database from the dropdown. Some databases require SHOW TABLES permission.
Check database schema selection - PostgreSQL users need to select the correct schema.
Columns not displayed correctly
Verify that Adminer version matches your database requirements. Some PostgreSQL types need recent Adminer versions for proper display.
Try clearing browser cache or using incognito mode to rule out display caching issues.
🔐 Security Concerns
CSRF/XSS concerns
Adminer uses PHP's internal session handling. Ensure session.cookie_secure is set to true in production.
Use HTTPS for secure connections when using Adminer in production environments.
Brute force attacks
Use HTTP authentication in front of Adminer or restrict access with IPs. Adminer itself doesn't implement login throttling.
⚙️ Advanced Troubleshooting
Performance issues
Add $dual = true; to Adminer config to enable dual queries. Some operations are much faster.
Monitor PHP memory limit and increase if necessary for large database operations: memory_limit=256M
UTF-8 Encoding problems
Ensure all layers (DB, Adminer, connection) use same charset. For MySQL add ->set_charset('utf8'); to connection.