DB Linker

Database connection for master/slaves setup. This package provides drivers for DBAL. MasterSlavesDriver for auto switching between a master and slaves servers & RetryDriver for retrying query when some errors occurs.

Installation

run composer require ezweb/dblinker

Configuration

Master/Slaves connection

A MysqlMasterSlavesConnection wraps a mysql master connection & one or more mysql slaves connection. It execute "READ" queries on one of the slaves connections and "WRITE" queries on the master connection.

// master and slaves configuration
$master = [
    'driver' => 'mysqli',
    'host' => $masterHostname,
    'user' => $masterUsername,
    'password' => $masterPassword,
    'dbname' => $masterDb,
];

$slaves = [
    [
        'driver' => 'mysqli',
        'host' => $slave1Hostname,
        'user' => $slave1Username,
        'password' => $slave1Password,
        'dbname' => $slave1Db,
        'weight' => $slave1Weight,
    ],
    /** other slaves params **/
];

// connection configuration
$params = [
    'master' => $master,
    'slaves' => $slaves,
    'driverClass' => 'Ez\DbLinker\Driver\MysqlMasterSlavesDriver',
];

// Doctrine\DBAL\Configuration
$connection = Doctrine\DBAL\DriverManager::getConnection($params);

var_dump($connection->fetchColumn('SELECT 1')); // slave
var_dump($connection->exec('INSERT INTO…')); // master

Retry connection

A MysqlRetryConnection wraps another mysql connection. Its goal is to transparently re-execute queries that provokes erros when it's possible to recover automatically.

// master and slaves configuration
$params = [
    'connectionParams' => [
        /** mysql master/slaves, mysqli or pdo_mysql parameters **/
    ],
    'driverClass' => 'Ez\DbLinker\Driver\MysqlRetryDriver',
    'retryStrategy' => new Ez\DbLinker\RetryStrategy\MysqlRetryStrategy,
]

// Doctrine\DBAL\Configuration
$connection = Doctrine\DBAL\DriverManager::getConnection($params);

var_dump($connection->fetchColumn('SELECT 1')); // nothing special
var_dump($connection->exec('SET SESSION WAIT_TIMEOUT = 1'));
sleep(2);
var_dump($connection->fetchColumn('SELECT 1')); // Connection will catch "MySQL has gone away", re-execute the query and return the results as if nothing happened

Usage

When using Doctrine\DBAL\DriverManager, the $connection it returns is an instance of Doctrine\DBAL\Connection, that wraps one or more *Connection. Take a look at its documentation for more information.

Note: You can nest a MysqlMasterSlavesConnection in a MysqlRetryConnection.

Tests

To run the test suite, you need Docker & Docker-Compose:

docker-compose run composer install
docker-compose run behat