Auto reconnect on Doctrine MySql has gone away exceptions on doctrine/dbal >=2.3, <3.0.

$ composer require facile-it/doctrine-mysql-come-back ^1.8

In order to use DoctrineMySQLComeBack you have to set wrapperClass and driverClass connection params. You can choose how many times Doctrine should be able to reconnect, setting x_reconnect_attempts driver option. Its value should be an int.

An example of configuration at connection instantiation time:

use Doctrine\DBAL\Configuration;
use Doctrine\DBAL\DriverManager;

$config = new Configuration();

//..

$connectionParams = array(
    'dbname' => 'mydb',
    'user' => 'user',
    'password' => 'secret',
    'host' => 'localhost',
    // [doctrine-mysql-come-back] settings
    'wrapperClass' => 'Facile\DoctrineMySQLComeBack\Doctrine\DBAL\Connection',
    'driverClass' => 'Facile\DoctrineMySQLComeBack\Doctrine\DBAL\Driver\PDOMySql\Driver',
    'driverOptions' => array(
        'x_reconnect_attempts' => 3
    )
);

$conn = DriverManager::getConnection($connectionParams, $config);

//..

An example of yaml configuration on Symfony 2 projects:

# Doctrine example Configuration
doctrine:
    dbal:
        default_connection: %connection_name%
        connections:
            %connection_name%:
                host:     %database_host%
                port:     %database_port%
                dbname:   %database_name%
                user:     %database_user%
                password: %database_password%
                charset:  UTF8
                wrapper_class: 'Facile\DoctrineMySQLComeBack\Doctrine\DBAL\Connection'
                driver_class: 'Facile\DoctrineMySQLComeBack\Doctrine\DBAL\Driver\PDOMySql\Driver'
                options:
                    x_reconnect_attempts: 3

If you are setting up your database connection using a DSN/database_url env variable (like the Doctrine Symfony Flex recipe suggests) you need to remove the protocol from your database url. Otherwise, Doctrine is going to ignore your driver_class configuration and use the default protocol driver, which will lead you to an error.

doctrine:
    dbal:
        connections:
            default:
                # DATABASE_URL needs to be without driver protocol.  
                # use "//db_user:[email protected]:3306/db_name"
                # instead of "mysql:https://db_user:[email protected]:3306/db_name" 
                url: '%env(resolve:DATABASE_URL)%'
                wrapper_class: 'Facile\DoctrineMySQLComeBack\Doctrine\DBAL\Connection'
                driver_class: 'Facile\DoctrineMySQLComeBack\Doctrine\DBAL\Driver\PDOMySql\Driver'
                options:
                    x_reconnect_attempts: 3

An example of configuration on Zend Framework 2/3 projects:

return [
    'doctrine' => [
        'connection' => [
            'orm_default' => [
                'driverClass' => \Facile\DoctrineMySQLComeBack\Doctrine\DBAL\Driver\PDOMySql\Driver::class,
                'wrapperClass' => \Facile\DoctrineMySQLComeBack\Doctrine\DBAL\Connection::class,
                'params' => [
                    'host' => 'localhost',
                    'port' => '3307',
                    'user' => '##user##',
                    'password' => '##password##',
                    'dbname' => '##database##',
                    'charset' => 'UTF8',
                    'driverOptions' => [
                        'x_reconnect_attempts' => 9,
                    ]
                ],
            ],
        ],
    ],
];

You can use wrapper class Facile\DoctrineMySQLComeBack\Doctrine\DBAL\Connections\MasterSlaveConnection if you are using master / slave Doctrine configuration.

To force a reconnection try after a long running task you can call

$em->getConnection()->refresh();

before performing any other operation different from SELECT.

Instead, in case your next query will be a SELECT, reconnection will be automagically done.

From v1.6 automagically reconnection is enabled also during $em->getConnection()->beginTransaction() calls, and this works also during simple $em->flush(), if out of a previous transaction.

Thanks to Dieter Peeters and his proposal on DBAL-275. Check it out if you are using doctrine/dbal <2.3.