tl;dr: ./gradlew test
In our current project we were struggling with the existing Hibernate/JPA setup in combination with Kotlin.
The misconfiguration of the project lead to a massive amount of unnecessary SELECT statements at the database, because the lazy loading of related entities was not working as expected and all entities were fetched eagerly from the database which lead to severe performance issues.
In combination with Kotlin, some details need to be considered in the configuration. If the configuration is correct, even data classes for the entities are working without an issue.
- Entity id: The entity id should be nullable - if it's not, a placeholder value needs to be set during creation, but this placeholder will make hibernate perform a select before every insert, to find out if the operation is an insert or an update
- Level2 Cache only works across transactions. A cache hit for an existing entity will only occur, after the entity was put into the cache and another translation tries to access this entity again
- For a custom repository query to be cached by hibernate, it is not enough to set
use_query_cache: truein application.yaml. The custom query also needs a@QueryHintsannotation instruction hibernate to cache this query