2006 php network_error ai_generated true

PDOException: SQLSTATE[HY000] [2006] MySQL server has gone away in /var/www/app/src/Database/Connection.php:42

ID: php/pdo-mysql-server-has-gone-away

Also available as: JSON · Markdown · 中文

85%Fix Rate

88%Confidence

1Evidence

2023-11-20First Seen

Version Compatibility

Version	Status	Introduced	Deprecated	Notes
PHP 7.4	active	—	—	—
PHP 8.1	active	—	—	—
PHP 8.2	active	—	—	—
MySQL 5.7	active	—	—	—
MySQL 8.0	active	—	—	—

Root Cause

The MySQL server closed the connection due to a timeout (wait_timeout or interactive_timeout), a packet size exceeding max_allowed_packet, or a server crash/restart, and the PHP PDO connection was not re-established.

generic

中文

MySQL服务器因超时（wait_timeout或interactive_timeout）、数据包大小超过max_allowed_packet或服务器崩溃/重启而关闭连接，且PHP PDO连接未重新建立。

Official Documentation

https://dev.mysql.com/doc/refman/8.0/en/gone-away.html

Workarounds

75% success Increase MySQL's wait_timeout and interactive_timeout in my.cnf, e.g., set wait_timeout=28800; interactive_timeout=28800. Then restart MySQL.
```
Increase MySQL's wait_timeout and interactive_timeout in my.cnf, e.g., set wait_timeout=28800; interactive_timeout=28800. Then restart MySQL.
```
70% success Increase max_allowed_packet in my.cnf to handle large queries, e.g., set max_allowed_packet=64M. Restart MySQL.
```
Increase max_allowed_packet in my.cnf to handle large queries, e.g., set max_allowed_packet=64M. Restart MySQL.
```
90% success Implement connection retry logic in PHP: catch the exception and reconnect using a new PDO instance. Example: try { $stmt = $pdo->query('SELECT 1'); } catch (\PDOException $e) { if ($e->getCode() == 2006) { $pdo = new PDO($dsn, $user, $pass); $stmt = $pdo->query('SELECT 1'); } }
```
Implement connection retry logic in PHP: catch the exception and reconnect using a new PDO instance. Example:
try {
    $stmt = $pdo->query('SELECT 1');
} catch (\PDOException $e) {
    if ($e->getCode() == 2006) {
        $pdo = new PDO($dsn, $user, $pass);
        $stmt = $pdo->query('SELECT 1');
    }
}
```

中文步骤

Increase MySQL's wait_timeout and interactive_timeout in my.cnf, e.g., set wait_timeout=28800; interactive_timeout=28800. Then restart MySQL.

Increase max_allowed_packet in my.cnf to handle large queries, e.g., set max_allowed_packet=64M. Restart MySQL.

Implement connection retry logic in PHP: catch the exception and reconnect using a new PDO instance. Example:
try {
    $stmt = $pdo->query('SELECT 1');
} catch (\PDOException $e) {
    if ($e->getCode() == 2006) {
        $pdo = new PDO($dsn, $user, $pass);
        $stmt = $pdo->query('SELECT 1');
    }
}

Dead Ends

Common approaches that don't work:

70% fail
The error is caused by MySQL's timeout, not PHP's execution time; changing PHP settings does not prevent the server from closing idle connections.
50% fail
Persistent connections can mask the issue but may lead to stale connections being reused, causing the same error later; they also consume server resources.
80% fail
Restarting temporarily reopens connections, but the underlying timeout or packet size issue remains, causing the error to recur.