How to fix ERROR 1030: Got an error reading communication packets in MySQL

# On Linux/Unix:
tail -200 /var/log/mysql/error.log

# On Windows:
type "C:\ProgramData\MySQL\MySQL Server 8.0\error.log"

# Or query MySQL directly:
show variables like 'log_error';

SHOW STATUS LIKE 'Aborted%';

# Check current timeout settings:
mysql> SHOW VARIABLES LIKE '%timeout%';

# Interactive connections (usually clients, like mysql CLI):
# Default: 28800 seconds (8 hours)
set global interactive_timeout = 86400;

# Non-interactive connections (usually applications):
# Default: 28800 seconds (8 hours)
set global wait_timeout = 86400;

# Connection setup timeout:
# Default: 10 seconds
set global connect_timeout = 20;

[mysqld]
wait_timeout = 86400
interactive_timeout = 86400
connect_timeout = 20

sudo systemctl restart mysql

# Check current limit (default: 64 MB in MySQL 8.0):
mysql> SHOW VARIABLES LIKE 'max_allowed_packet';

# Increase the limit temporarily:
set global max_allowed_packet = 268435456;  # 256 MB

# Persist in configuration:
# Edit /etc/mysql/mysql.conf.d/mysqld.cnf:
[mysqld]
max_allowed_packet = 256M

# Restart MySQL:
sudo systemctl restart mysql

# Check current values (default: 30 seconds):
mysql> SHOW VARIABLES LIKE 'net_\w*_timeout';

# Increase for slow networks or high-latency connections:
set global net_read_timeout = 60;
set global net_write_timeout = 60;

# Persist in configuration:
# Edit /etc/mysql/mysql.conf.d/mysqld.cnf:
[mysqld]
net_read_timeout = 60
net_write_timeout = 60

# Restart:
sudo systemctl restart mysql

import mysql.connector
conn = mysql.connector.connect(host="localhost", user="user", password="pass", database="db")
try:
    cursor = conn.cursor()
    cursor.execute("SELECT * FROM users")
    results = cursor.fetchall()
finally:
    cursor.close()
    conn.close()  # CRITICAL: Always close

const connection = mysql.createConnection({host: 'localhost', user: 'user', password: 'pass'});
try {
    const results = await connection.execute('SELECT * FROM users');
finally {
    await connection.end();  // CRITICAL: Always close
}

$pdo = new PDO('mysql:host=localhost;dbname=db', 'user', 'pass');
try {
    $stmt = $pdo->prepare('SELECT * FROM users');
    $stmt->execute();
} finally {
    $pdo = null;  // Close connection
}

backend mysql_backend
    timeout connect 10s
    timeout server 300s   # Must be longer than MySQL wait_timeout
    timeout client 300s   # Must be longer than MySQL interactive_timeout

# Test direct connection to MySQL:
mysql -h 127.0.0.1 -P 3306 -u user -p

# From a remote client, test through the proxy:
mysql -h proxy.example.com -P 3306 -u user -p

# Test latency and packet loss to MySQL host:
ping -c 10 mysql.example.com

# For Windows:
ping -n 10 mysql.example.com

# Run a continuous ping to see if latency spikes:
ping mysql.example.com

# Check TCP connection stats:
netstat -s | grep -i tcp
# or on newer systems:
ss -s

# On Linux, check for network errors:
ethtool eth0
netstat -i

# Gracefully stop MySQL:
sudo systemctl stop mysql

# Verify it stopped:
ps aux | grep mysqld

# Start MySQL:
sudo systemctl start mysql

# Check status:
sudo systemctl status mysql

# Verify it is responding:
mysql -u root -p -e "SELECT 1;"
mysql -u root -p -e "SHOW VARIABLES LIKE 'wait_timeout';

tail -f /var/log/mysql/error.log