How to fix ERROR 1152: Aborted connection in MySQL

# On Linux/Mac, common locations:
cat /var/log/mysql/error.log | grep "Aborted connection"

# Example output:
# 2024-01-15 10:23:45 [Warning] Aborted connection 45123 to db: 'myapp' user: 'appuser' host: '192.168.1.100' (Got timeout reading communication packets)

SET GLOBAL wait_timeout = 28800;
SET GLOBAL interactive_timeout = 28800;
SET GLOBAL net_read_timeout = 300;
SET GLOBAL net_write_timeout = 300;

[mysqld]
wait_timeout = 28800
interactive_timeout = 28800
net_read_timeout = 300
net_write_timeout = 300

sudo systemctl restart mysql

SET GLOBAL max_allowed_packet = 67108864;

[mysqld]
max_allowed_packet = 67108864

sudo systemctl restart mysql

SHOW VARIABLES LIKE 'max_allowed_packet';

// Node.js example with mysql2
const connection = await mysql.createConnection({ ... });
try {
  const result = await connection.execute('SELECT * FROM users');
  return result;
} finally {
  await connection.end(); // Always close
}

const pool = mysql.createPool({
  host: 'localhost',
  user: 'appuser',
  password: 'password',
  database: 'myapp',
  waitForConnections: true,
  connectionLimit: 10,
  queueLimit: 0,
});

pool.getConnection((err, connection) => {
  if (err) throw err;
  connection.query('SELECT * FROM users', (err, result) => {
    connection.release();
  });
});

// Ping every 5 minutes to keep connection alive
setInterval(() => {
  connection.ping((err) => {
    if (err) console.error('Ping error:', err);
  });
}, 5 * 60 * 1000);

# From client to MySQL server
ping <mysql-host>
telnet <mysql-host> 3306
nc -zv <mysql-host> 3306

# On Linux, check if port 3306 is open
sudo ufw status
sudo iptables -L -n | grep 3306

# On Linux, edit /etc/mysql/my.cnf:
[mysqld]
interactive_timeout = 28800
wait_timeout = 28800

# Watch log in real-time
tail -f /var/log/mysql/error.log | grep -E "Aborted|ERROR"

# Count aborted connections in last hour
grep --text "Aborted connection" /var/log/mysql/error.log | wc -l

SHOW STATUS LIKE 'Aborted%';

+-----------------------+-------+
| Variable_name         | Value |
+-----------------------+-------+
| Aborted_clients       | 5     | -- Client aborted (app didn't close)
| Aborted_connects      | 2     | -- Failed connection attempts
+-----------------------+-------+