README

This package provides interface contracts for database connection management with read/write splitting support. Implementations can be used in any PHP environment, including long-running processes like RoadRunner, Swoole, or FrankenPHP.

Important: This is a contract-only package. It defines interfaces but does not provide implementations.

Features

• Read/Write Splitting: Separate connections for primary (write) and replica (read) databases
• Connection Management: Handle connection lifecycle, validation, and reconnection
• Automatic Load Balancing: Distribute read operations across multiple replicas
• Failover Support: Automatic failover when replicas become unhealthy
• Statistics Tracking: Monitor read/write counts and failover events

Requirements

• PHP >= 8.2
• ext-pdo

Installation

composer require jardispsr/dbconnection

Interfaces

DbConnectionInterface

Core interface for database connections with support for:

• PDO instance access (pdo())
• Connection validation (isConnected())
• Connection lifecycle management (disconnect(), reconnect())
• Transaction management (beginTransaction(), commit(), rollback(), inTransaction())
• Metadata access (getDriverName(), getDatabaseName())
• Default PDO options constant (DEFAULT_OPTIONS)

ConnectionPoolInterface

Interface for read/write splitting in database replication setups:

• getWriter(): Returns a DbConnectionInterface for write operations (primary database)
• getReader(): Returns a DbConnectionInterface for read operations (replica database)
• getStats(): Returns array with statistics: {reads: int, writes: int, failovers: int, readers: int}
• resetStats(): Resets all statistics counters to zero

Implementations are expected to provide:

• Lazy connection creation
• Load balancing across multiple replicas
• Automatic failover when replicas become unhealthy
• Fallback to writer when no readers are configured

Usage Example

use JardisPsr\DbConnection\ConnectionPoolInterface;
use JardisPsr\DbConnection\DbConnectionInterface;

// Assuming you have an implementation of ConnectionPoolInterface
// (this package only provides the interface contracts)

/** @var ConnectionPoolInterface $pool */

// Write operations - use the primary database
$writer = $pool->getWriter();
$pdo = $writer->pdo();

$stmt = $pdo->prepare('INSERT INTO users (name, email) VALUES (?, ?)');
$stmt->execute(['John Doe', 'john@example.com']);

// Read operations - use a replica database
$reader = $pool->getReader();
$pdo = $reader->pdo();

$stmt = $pdo->prepare('SELECT * FROM users WHERE id = ?');
$stmt->execute([1]);
$user = $stmt->fetch();

// Monitor pool statistics
$stats = $pool->getStats();
echo sprintf(
    "Reads: %d, Writes: %d, Failovers: %d, Readers: %d\n",
    $stats['reads'],
    $stats['writes'],
    $stats['failovers'],
    $stats['readers']
);

// Reset statistics for new monitoring period
$pool->resetStats();

Why Read/Write Splitting?

In database replication setups, the primary database handles writes while replicas handle reads. Read/write splitting:

1. Scales read operations: Distribute read load across multiple replicas
2. Reduces primary load: Offload read queries from the primary database
3. Improves performance: Read queries don't compete with write operations
4. Provides failover: Automatically handle replica failures
5. Enables monitoring: Track read/write patterns and failover events

This approach is particularly beneficial in long-running PHP processes (RoadRunner, Swoole, FrankenPHP) where database connections persist across multiple requests.

Development

Code Quality

# Run PHPStan (level 8)
make phpstan

# Run PHP CodeSniffer (PSR-12)
make phpcs

All commands require Docker Compose and a .env file (see Makefile for details).

License

MIT License - see LICENSE file for details.

Support

• Issues: https://github.com/JardisPsr/dbconnection/issues
• Email: devcore@headgent.dev

Authors

• Jardis Core Development Team