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Database
Connection Pool

Connection Pool

The ODY framework implements a robust database connection pool that leverages Swoole’s coroutines for high-performance database access. Here’s an overview of how it works:

Core Concepts

The connection pool manages a collection of database connections that can be borrowed, used, and returned without the overhead of establishing new connections for each database operation.

Key Features

  • Coroutine-Aware: Binds connections to Swoole coroutines for automatic management
  • Connection Reuse: Maintains a pool of pre-established connections to reduce connection overhead
  • Auto-Return: Automatically returns connections to the pool when coroutines complete
  • Configurable Sizing: Adjustable pool size based on workload requirements
  • Connection Health Checks: Validates connections before they’re borrowed
  • Leak Detection: Identifies and logs potential connection leaks
  • Connection Lifecycle Management: Handles connection creation, validation, and cleanup

How It Works

  1. Initialization:

    ConnectionManager::initPool($config, $name);

    This creates a new connection pool with the specified configuration.

  2. Borrowing a Connection:

    $connection = ConnectionManager::getConnection($name);

    This gets a PDO connection from the pool, binding it to the current coroutine.

  3. Auto-Return: When the coroutine completes, the connection is automatically returned to the pool if autoReturn is enabled.

  4. Manual Return: If autoReturn is disabled, you must explicitly return connections:

    ConnectionManager::getPool($name)->return($connection);

  5. Pool Management: The pool automatically scales between minimum idle connections and maximum size based on demand.

Configuration Options

  • size: Maximum number of connections in the pool
  • minimumIdle: Minimum number of idle connections to maintain
  • idleTimeoutSec: Time after which idle connections are removed
  • maxLifetimeSec: Maximum lifetime of a connection before recreation
  • borrowingTimeoutSec: Maximum time to wait when borrowing a connection
  • autoReturn: Whether to automatically return connections
  • bindToCoroutine: Whether to bind connections to coroutines

Connection Lifecycle

  1. Creation: New connections are created as needed up to the pool size limit
  2. Validation: Before a connection is borrowed, it’s checked for validity
  3. Usage: The connection is marked as in-use while borrowed
  4. Return: The connection is returned to the pool after use
  5. Maintenance: Idle connections are periodically checked and renewed
  6. Cleanup: Connections are properly closed when the pool is shutdown

By using this connection pool, database operations become more efficient, especially under high concurrency, as connection creation overhead is minimized.

DBAL