CODESAMPLE

Master-Slave - PHP

Master-Slave PHP

The Master-Slave pattern involves a primary database (Master) handling all write operations, while one or more read-only replicas (Slaves) serve read requests. This improves performance by distributing the read load and provides read scalability. The PHP code demonstrates a simple abstraction for interacting with a Master-Slave setup using PDO. A DatabaseManager class handles connection routing based on the operation type (read or write). The getMaster() and getSlave() methods return appropriate PDO connections. This approach is idiomatic PHP as it leverages PDO for database abstraction and uses a class to encapsulate the connection logic, promoting maintainability and separation of concerns.

<?php

class DatabaseManager {
    private $masterConfig;
    private $slaveConfig;
    private $masterConnection;
    private $slaveConnection;

    public function __construct(array $masterConfig, array $slaveConfig) {
        $this->masterConfig = $masterConfig;
        $this->slaveConfig = $slaveConfig;
    }

    private function getMaster(): PDO {
        if ($this->masterConnection === null) {
            $dsn = "{$this->masterConfig['driver']}:host={$this->masterConfig['host']};dbname={$this->masterConfig['dbname']}";
            $this->masterConnection = new PDO($dsn, $this->masterConfig['user'], $this->masterConfig['password']);
            $this->masterConnection->setAttribute(PDO::ATTR_ERRMODE, PDO::ERRMODE_EXCEPTION);
        }
        return $this->masterConnection;
    }

    private function getSlave(): PDO {
        if ($this->slaveConnection === null) {
            $dsn = "{$this->slaveConfig['driver']}:host={$this->slaveConfig['host']};dbname={$this->slaveConfig['dbname']}";
            $this->slaveConnection = new PDO($dsn, $this->slaveConfig['user'], $this->slaveConfig['password']);
            $this->slaveConnection->setAttribute(PDO::ATTR_ERRMODE, PDO::ERRMODE_EXCEPTION);
        }
        return $this->slaveConnection;
    }

    public function query(string $sql, array $params = [], bool $isWrite = false): array {
        try {
            $connection = $isWrite ? $this->getMaster() : $this->getSlave();
            $statement = $connection->prepare($sql);
            $statement->execute($params);
            return $statement->fetchAll(PDO::FETCH_ASSOC);
        } catch (PDOException $e) {
            // Log the error or handle it appropriately
            error_log("Database Error: " . $e->getMessage());
            return [];
        }
    }
}

// Example Usage:
$masterConfig = [
    'driver' => 'mysql',
    'host' => 'localhost',
    'dbname' => 'mydatabase',
    'user' => 'master_user',
    'password' => 'master_password',
];

$slaveConfig = [
    'driver' => 'mysql',
    'host' => 'localhost',
    'dbname' => 'mydatabase',
    'user' => 'slave_user',
    'password' => 'slave_password',
];

$dbManager = new DatabaseManager($masterConfig, $slaveConfig);

// Write operation
$dbManager->query("INSERT INTO users (name) VALUES ('John Doe')", [], true);

// Read operation
$users = $dbManager->query("SELECT * FROM users", [], false);
print_r($users);

?>