README.md

Hibernate 2nd Level Cache with Redis

• Reduces database round-trips by caching frequently accessed data
• Provides quick access to cached entities and associations
• Operates at the SessionFactory level, shared across all sessions
• Configurable with various cache providers (Redis, Ehcache, Infinispan)
• Complements the session-scoped first level cache

Leverages Redis to cache frequently accessed entities and associations for faster read performance, reducing round-trips to the database.

Compatibility Note: This implementation has been tested with Redis version 7.4.1 and above.

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Table of Contents

• Hibernate 2nd Level Cache with Redis
  • Run tests
  • Run locally
  • Using Testcontainers at Development Time
  • Useful Links
  • Notes
  • Caching Collections (One-Many & Many-Many Relations)
    • Example Configuration

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Run tests

./mvnw clean verify

Run locally

docker-compose -f docker/docker-compose.yml up -d
./mvnw spring-boot:run -Dspring-boot.run.profiles=local

Using Testcontainers at Development Time

You can run TestApplication.java from your IDE directly. You can also run the application using Maven as follows:

./mvnw spring-boot:test-run

Useful Links

• Swagger UI: http://localhost:8080/swagger-ui.html
• Actuator Endpoint: http://localhost:8080/actuator

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Notes

• We need to explicitly set the querycacheHint to customerqueries for enabling 2nd level cache
• This is enabled only for SessionFactory(i.e as soon as application is closed it will be deleted)

Caching Collections (One-Many & Many-Many Relations)

Collection caching allows you to cache entire collections of associated entities. These collections can be part of your domain model, such as one-to-many or many-to-many relationships between entities.

Collection caching is valuable when dealing with associations between entities that are frequently loaded and where caching can lead to significant performance gains. When you enable collection caching, Hibernate caches entire collections, such as lists or sets, associated with an entity.

When Hibernate caches a collection, it doesn’t cache the entire collection of entities but rather caches the IDs of the entities contained in the collection.

• Caching only the IDs reduces memory usage compared to caching the entire collection of entities.
• When a collection is updated, only the relevant IDs need to be invalidated in the cache, rather than the entire collection. This minimizes cache invalidation overhead.

Example Configuration

@Entity
public class Department {
    @Cache(usage = CacheConcurrencyStrategy.READ_WRITE)
    @OneToMany(mappedBy = "department")
    private List<Employee> employees;
}