How to fix ERROR 1184: Aborted connection to database in MySQL

# Test connection with explicit credentials
mysql -h 127.0.0.1 -u root -p'yourpassword' mysql

# Check if the user exists and has proper host permissions
mysql> SELECT user, host FROM mysql.user WHERE user='yourusername';

# Grant privileges if needed
mysql> GRANT ALL PRIVILEGES ON *.* TO 'youruser'@'localhost' IDENTIFIED BY 'password';
mysql> FLUSH PRIVILEGES;

# On Linux, typical log location
sudo tail -50 /var/log/mysql/error.log

# On macOS with Homebrew
tail -50 /usr/local/var/mysql/$(hostname).err

# In MySQL client, check recent errors
mysql> SHOW ENGINE INNODB STATUS;

# Check current max_connections limit
mysql> SHOW VARIABLES LIKE 'max_connections';

# Temporarily increase for testing (resets on restart)
mysql> SET GLOBAL max_connections = 300;

# Make permanent by editing my.cnf or my.ini
[mysqld]
max_connections = 300

# Then restart MySQL
sudo systemctl restart mysql

# Test latency to MySQL server
ping -c 5 your-mysql-host

# Check if port 3306 is reachable
nc -zv your-mysql-host 3306

# On Linux, check firewall rules
sudo iptables -L -n | grep 3306
sudo firewall-cmd --list-all | grep 3306

# On Windows, check Windows Firewall
netsh advfirewall firewall show rule name="MySQL"

# Check server's TLS version settings
mysql> SHOW VARIABLES LIKE 'tls_version';

# Example output: tls_version = 'TLSv1.2,TLSv1.3'

# Check what the client is requesting
openssl s_client -connect your-mysql-host:3306 -tls1_2

# If you have an old client that only supports TLS 1.0, upgrade it
# OR lower the server's minimum TLS version (not recommended for security)

# Check current timeout settings
mysql> SHOW VARIABLES LIKE 'connect_timeout';
mysql> SHOW VARIABLES LIKE 'wait_timeout';
mysql> SHOW VARIABLES LIKE 'interactive_timeout';

# Increase connect_timeout (in seconds) in my.cnf
[mysqld]
connect_timeout = 30

# Then restart MySQL
sudo systemctl restart mysql

# For application-level pools, adjust pool connection timeout too
# Example: Node.js with mysql2
const connection = mysql.createConnection({
  host: 'localhost',
  user: 'root',
  password: 'password',
  connectTimeout: 30000, // 30 seconds in milliseconds
});

// Node.js example with mysql2/promise
const mysql = require('mysql2/promise');

const pool = mysql.createPool({
  host: 'localhost',
  user: 'root',
  password: 'password',
  database: 'mydb',
  waitForConnections: true,
  connectionLimit: 10, // Keep this well below server's max_connections
  queueLimit: 0,
});

// Good: Stagger connection creation
const connection = await pool.getConnection();
// ...
connection.release();

# Python example with mysql-connector
import mysql.connector
from mysql.connector import pooling

config = {
    "host": "localhost",
    "user": "root",
    "password": "password",
    "database": "mydb"
}

pool = pooling.MySQLConnectionPool(
    pool_name="mypool",
    pool_size=5, # Set well below server's max_connections
    pool_reset_session=True,
    **config
)

-- Check the current init_connect value
SHOW VARIABLES LIKE 'init_connect';

-- Reset to empty (via Azure portal or CLI)
-- Azure Portal: Settings > Server parameters > init_connect = ''

-- Via Azure CLI
az mysql server configuration set \
  --resource-group myResourceGroup \
  --server-name myserver \
  --name init_connect \
  --value ''