Crystal Database Connections

Introduction to Crystal Database Connections

In Crystal, database connections are managed using connection pools to improve efficiency and performance. This post will guide you through the fundamentals of setting up and using database connections in Crystal, ensuring that your applications can handle multiple database operations concurrently without significant overhead.

Understanding Connection Pools

A connection pool is a collection of database connections maintained so that they can be reused when future requests to the database are required. Reusing existing connections rather than opening a new one each time makes database operations more efficient and improves application performance.

Setting Up a Database Connection in Crystal

To connect to a database in Crystal, you need to use a database shard. The most commonly used shard for database connectivity is crystal-db, which provides a unified interface to connect to different database systems such as PostgreSQL, MySQL, and SQLite.

After adding the dependency to your shard.yml file, you can establish a connection to your desired database. Below is an example of connecting to a PostgreSQL database:

Configuring Connection Pools

Configuring your connection pool involves setting parameters such as the maximum number of connections and timeout settings. These configurations help manage resource usage and ensure your application can handle spikes in database requests.

In the example above, the pool size is set to 5, which means the application can maintain up to 5 open connections simultaneously. The timeout is set to 3000 milliseconds, dictating how long the application should wait for a connection to become available before throwing an error.

Best Practices for Database Connections

Here are some best practices to follow when working with database connections in Crystal:

• Always close connections when they are no longer needed to free up resources.
• Use connection pools to manage database connections efficiently.
• Monitor and adjust the pool size and timeout settings according to your application's requirements and load.
• Use transactions for operations that need to be atomic to ensure data integrity.