How do you configure MySQL connection pooling in Spring Boot?

Table of Contents

• Introduction
• Setting Up MySQL Connection Pooling
  • 1. Understand HikariCP: The Default Connection Pool
  • 2. Configure MySQL Connection Pooling in application.properties
    • Example: application.properties Configuration
  • 3. Using application.yml
  • 4. Monitor Connection Pooling
    • Add Actuator Dependency:
    • Enable Metrics in application.properties:
• Practical Examples
  • Example 1: Customizing Pool Size Based on Application Load
    • Example:
  • Example 2: Handling Slow Queries
• Conclusion

Introduction

MySQL connection pooling in Spring Boot helps improve the efficiency and performance of database interactions by reusing established connections instead of creating a new one for each request. This reduces the overhead of frequent connection establishment and teardown, which is especially beneficial in high-traffic applications. In this guide, we’ll explore how to configure MySQL connection pooling in Spring Boot using HikariCP, the default connection pool in Spring Boot.

Setting Up MySQL Connection Pooling

1. Understand HikariCP: The Default Connection Pool

Spring Boot uses HikariCP as its default connection pooling library because of its high performance and minimal overhead. HikariCP offers out-of-the-box configuration that works well for most use cases.

2. Configure MySQL Connection Pooling in application.properties

To configure MySQL connection pooling, define the connection pool settings in the application.properties or application.yml file.

Example: application.properties Configuration

3. Using application.yml

If you prefer YAML configuration, here’s how it looks:

4. Monitor Connection Pooling

To monitor the connection pool, enable metrics. Spring Boot’s Actuator can help with monitoring:

Add Actuator Dependency:

Enable Metrics in application.properties:

Access metrics by visiting the /actuator/metrics/hikari.pool.usage endpoint.

Practical Examples

Example 1: Customizing Pool Size Based on Application Load

Adjust the maximum-pool-size based on expected traffic:

• For light traffic: Set maximum-pool-size=10.
• For heavy traffic: Increase it, e.g., maximum-pool-size=50.

Example:

Example 2: Handling Slow Queries

If your database has occasional slow queries, increase connection-timeout:

This ensures the pool waits longer before timing out when acquiring a connection.

Conclusion

Configuring MySQL connection pooling in Spring Boot with HikariCP is straightforward and significantly enhances performance by reusing established connections. By customizing the pool settings like size, timeout, and idle configurations, you can optimize resource utilization and ensure smooth database interactions for your application.