Why Does My MySQL Connection Fail with Error 2006: 'MySQL Server Has Gone Away'?

Troubleshooting "MySQL Error 2006: MySQL Server Has Gone Away"

When faced with the infamous "MySQL server has gone away" error (2006), it's crucial to understand the root cause to effectively resolve it. While the conventional wisdom suggests adjusting the wait_timeout parameter, there's a less commonly known but often overlooked culprit: the max_allowed_packet setting.

In many cases, a low default value for max_allowed_packet can lead to this error. This parameter sets the maximum size of individual packets allowed in a connection. If your data transmission exceeds this limit, the connection will be terminated and the "MySQL server has gone away" error will occur.

To rectify this issue, modify the max_allowed_packet setting in the /etc/my.cnf file (under [mysqld]) to a larger value, such as 8 or 16 megabytes.

[mysqld]
max_allowed_packet=16M

Ensure the line is created if it doesn't exist, and it must be placed underneath [mysqld].

Additional Notes:

• This change can be made on your server while it's running, but it will be lost upon restarting the MySQL daemon.
• To permanently apply the setting, use SET GLOBAL max_allowed_packet=104857600 (sets it to 100MB).
• On Windows, ensure that the my.ini or my.cnf file is saved with ANSI encoding, not UTF-8.

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