Spring Boot + JPA2 + Hibernate - enable second level cache

Question

I'm using Spring Boot 1.2.5 with JPA2 to annotate entities (and hibernate as underlaying JPA implementation).

I wanted to use second level cache in that setup, so entities were annotated with @javax.persistence.Cacheable

I also added following in application.properties:

spring.jpa.properties.hibernate.cache.use_second_level_cache=true spring.jpa.properties.hibernate.cache.use_query_cache=true spring.jpa.properties.hibernate.cache.region.factory_class=org.hibernate.cache.ehcache.EhCacheRegionFactory 

During bootup hibernate complained about lack of EhCacheRegionFactory so I also added this to pom:

<dependency>     <groupId>org.hibernate</groupId>     <artifactId>hibernate-ehcache</artifactId> </dependency> 

But still queries like entityManager.find(Clazz.class, pk) are firing DB query instead of using cached data.

Any idea what is missing?

Answer 1

To sum everything (L2 cache and query cache) up:

The first thing to do is to add cache provider (I recommend using EhCache) to your classpath.

Hibernate < 5.3

Add the hibernate-ehcache dependency. This library contains EhCache 2 which is now discontinued.

<dependency>     <groupId>org.hibernate</groupId>     <artifactId>hibernate-ehcache</artifactId>     <version>your_hibernate_version</version> </dependency> 

Hibernate >=5.3

In newer versions of Hibernate caches implementing JSR-107 (JCache) API should be used. So there're 2 dependencies needed - one for JSR-107 API and the second one for the actual JCache implementation (EhCache 3).

<dependency>      <groupId>org.hibernate</groupId>      <artifactId>hibernate-jcache</artifactId>      <version>your_hibernate_version</version> </dependency>  <dependency>     <groupId>org.ehcache</groupId>     <artifactId>ehcache</artifactId>     <version>3.6.3</version>     <scope>runtime</scope> </dependency> 

Now let's move on to application.properties/yml file:

spring:   jpa:     #optional - show SQL statements in console.      show-sql: true      properties:       javax:         persistence:           sharedCache:              #required - enable selective caching mode - only entities with @Cacheable annotation will use L2 cache.             mode: ENABLE_SELECTIVE        hibernate:         #optional - enable SQL statements formatting.         format_sql: true          #optional - generate statistics to check if L2/query cache is actually being used.         generate_statistics: true         cache:           #required - turn on L2 cache.           use_second_level_cache: true           #optional - turn on query cache.           use_query_cache: true            region:             #required - classpath to cache region factory.             factory_class: org.hibernate.cache.ehcache.EhCacheRegionFactory  

For EhCache 3 (or Hibernate >=5.3) this region factory should be used:

factory_class: org.hibernate.cache.jcache.JCacheRegionFactory 

You can also enable TRACE level logging for Hibernate to verify your code and configuration:

logging:   level:     org:       hibernate:         type: trace 

Now let's move on to the code. To enable L2 caching on your entity you need to add those two annotations:

@javax.persistence.Cacheable @org.hibernate.annotations.Cache(usage = CacheConcurrencyStrategy.READ_WRITE) //Provide cache strategy. public class MyEntity {   ... } 

Note - if you want to cache your @OneToMany or @ManyToOne relation - add @Cache annotation over this field as well.

And to enable query cache in your spring-data-jpa repository you need to add proper QueryHint.

public class MyEntityRepository implements JpaRepository<MyEntity, Long> {    @QueryHints(@QueryHint(name = org.hibernate.annotations.QueryHints.CACHEABLE, value = "true"))   List<MyEntity> findBySomething(String something);  } 

Now verify via logs if your query is executed only once and remember to turn off all the debug stuff - now you're done.

Note 2 - you can also define missing cache strategy as create if you want to stay with defaults without getting warnings in your logs:

spring:   jpa:     properties:       hibernate:         javax:           cache:             missing_cache_strategy: create 

Answer 2

Well after some more digging here's what I was missing in application.properties:

spring.jpa.properties.javax.persistence.sharedCache.mode=ALL 

Hope it helps someone :)