Spring 引导应用程序的 Hibernate 缓存（Infinispan，Hazelcast，理想可扩展）

Question

I have a Spring Boot application which retrieves (and stores) data via Hibernate. Hibernate is connected to a MySQL database. I optimised the database requests slightly with some entity graphs to join some tables before retrieving them from the database. Now, I want the most common objects (which are not changed too often) to be stored in a cache.

I tried caching via Infinispan and Hazelcast. I changed configurations here and there but somehow the entities are ALWAYS retrieved from the database.

For Halzelcast, I added the following three dependencies in my pom.xml . Even though hazelcast-hibernate seems to be integrated in hazelcast-spring , I need the third dependency because otherwise the region factory would not be available.

<dependency>
    <groupId>com.hazelcast</groupId>
    <artifactId>hazelcast</artifactId>
    <version>3.12.2</version>
</dependency>
<dependency>
    <groupId>com.hazelcast</groupId>
    <artifactId>hazelcast-spring</artifactId>
    <version>3.12.2</version>
</dependency>
<dependency>
    <groupId>com.hazelcast</groupId>
    <artifactId>hazelcast-hibernate53</artifactId>
    <version>1.3.2</version>
</dependency>

The following settings should be sufficient for using Hazelcast as a Hibernate cache. But it does not work. I still see the same SQL queries in the logs like before.

spring.jpa.properties.hibernate.cache.use_second_level_cache=true
spring.jpa.properties.hibernate.cache.region.factory_class=com.hazelcast.hibernate.HazelcastLocalCacheRegionFactory

The HazelcastLocalCacheRegionFactory should be used because the performance should be slightly better and ram is (currently) not such a huge issue. Nevertheless, I also welcome different approaches.

The relevant entities get both annotations ( @Cacheable and @Cache ).

@Entity(name = "business_units")
@Getter @Setter
@Cacheable
@org.hibernate.annotations.Cache(usage = CacheConcurrencyStrategy.READ_WRITE)
public class BusinessUnit extends Auditable<String> implements Serializable {

    private static final long serialVersionUID = -6994142588281279518L;

    @Id
    @GeneratedValue(strategy = GenerationType.AUTO, generator = "native")
    @GenericGenerator(name = "native", strategy = "native")
    @Column(nullable = false, name = "id")
    private Integer id;

    @ManyToOne(fetch = FetchType.EAGER)
    @JoinColumn(name = "allocated_responsibility_id", referencedColumnName = "id")
    @org.hibernate.annotations.Cache(usage = CacheConcurrencyStrategy.READ_WRITE)
    private ProductManager allocatedResponsibility;

    // Some other attributes, getters and setters...

    @Override
    public boolean equals(Object o) {
        if (this == o) return true;
        if (!(o instanceof BusinessUnit)) return false;
        BusinessUnit that = (BusinessUnit) o;
        return id != null && id.equals(that.id);
    }

    @Override
    public int hashCode() {
        return 31;
    }
}

The same was also tried with Infinispan (different dependencies but same non-existing result).

I intend to use an external provider because the app should be scalable. Without paying attention to this, the cache would not mirror the database correctly anymore.

An embedded cache should be used because an extra server for Hazelcast or Infinispan would be too complicated to maintain.

I have no idea why nothing changes (okay, i see that Hazelcast starts). Another idea I had is using a query cache instead of a Hibernate cache. But this would require more attention to ensure synchronous database and cache. Furthermore, the app could benefit less from this.

Could you please tell me why it does not work and what to change that it works?

Update: Add Statistics

I tried below suggestions and added the statistics like @Nicolas suggested.

spring.jpa.properties.hibernate.generate_statistics=true

When I first load such a page, the data gets requested from the database and put into the cache (L2C).

1519200 nanoseconds spent acquiring 1 JDBC connections;
0 nanoseconds spent releasing 0 JDBC connections;
1759800 nanoseconds spent preparing 1 JDBC statements;
4144000 nanoseconds spent executing 1 JDBC statements;
0 nanoseconds spent executing 0 JDBC batches;
161900 nanoseconds spent performing 3 L2C puts;
0 nanoseconds spent performing 0 L2C hits;
0 nanoseconds spent performing 0 L2C misses;
0 nanoseconds spent executing 0 flushes (flushing a total of 0 entities and 0 collections);
0 nanoseconds spent executing 0 partial-flushes (flushing a total of 0 entities and 0 collections)

But when I access the site again (or perform any other action which should hit the cache), the data gets requested from the database again (and put into the cache).

The logs when accessing the page again:

2019-10-08 12:51:38.399  INFO 17028 --- [nio-8080-exec-8] i.StatisticalLoggingSessionEventListener : Session Metrics {
    0 nanoseconds spent acquiring 0 JDBC connections;
    0 nanoseconds spent releasing 0 JDBC connections;
    0 nanoseconds spent preparing 0 JDBC statements;
    0 nanoseconds spent executing 0 JDBC statements;
    0 nanoseconds spent executing 0 JDBC batches;
    0 nanoseconds spent performing 0 L2C puts;
    0 nanoseconds spent performing 0 L2C hits;
    0 nanoseconds spent performing 0 L2C misses;
    0 nanoseconds spent executing 0 flushes (flushing a total of 0 entities and 0 collections);
    0 nanoseconds spent executing 0 partial-flushes (flushing a total of 0 entities and 0 collections)
}
2019-10-08 12:51:38.404 DEBUG 17028 --- [nio-8080-exec-8] org.hibernate.SQL                        : 
    select
        businessun0_.id as id1_0_0_,
        productman1_.id as id2_9_1_,
        employee2_.id as id1_4_2_,
        businessun0_.created_by as created_2_0_0_,
        businessun0_.created_date as created_3_0_0_,
        businessun0_.last_modified_by as last_mod4_0_0_,
        businessun0_.last_modified_date_time as last_mod5_0_0_,
        businessun0_.allocated_responsibility_id as allocate7_0_0_,
        businessun0_.name as name6_0_0_,
        productman1_.employee_id as employee3_9_1_,
        employee2_.created_by as created_2_4_2_,
        employee2_.created_date as created_3_4_2_,
        employee2_.last_modified_by as last_mod4_4_2_,
        employee2_.last_modified_date_time as last_mod5_4_2_,
        employee2_.email_address as email_ad6_4_2_,
        employee2_.location as location7_4_2_,
        employee2_.name as name8_4_2_,
        employee2_.team as team9_4_2_ 
    from
        business_units businessun0_ 
    left outer join
        responsibilities productman1_ 
            on businessun0_.allocated_responsibility_id=productman1_.id 
    left outer join
        employees employee2_ 
            on productman1_.employee_id=employee2_.id
2019-10-08 12:51:38.412  INFO 17028 --- [nio-8080-exec-8] i.StatisticalLoggingSessionEventListener : Session Metrics {
    901000 nanoseconds spent acquiring 1 JDBC connections;
    0 nanoseconds spent releasing 0 JDBC connections;
    1075000 nanoseconds spent preparing 1 JDBC statements;
    1766400 nanoseconds spent executing 1 JDBC statements;
    0 nanoseconds spent executing 0 JDBC batches;
    166800 nanoseconds spent performing 3 L2C puts;
    0 nanoseconds spent performing 0 L2C hits;
    0 nanoseconds spent performing 0 L2C misses;
    0 nanoseconds spent executing 0 flushes (flushing a total of 0 entities and 0 collections);
    0 nanoseconds spent executing 0 partial-flushes (flushing a total of 0 entities and 0 collections)
}

Answer 1

I think the SQL will always be output by Hibernate, regardless whether the cache activates or not. If you want to make sure that your cache is used, please activate Hibernate statistics:

spring.jpa.properties.hibernate.generate_statistics=true

On the firs request, it should output something like that:

Session Metrics {
    388816 nanoseconds spent acquiring 1 JDBC connections;
    0 nanoseconds spent releasing 0 JDBC connections;
    2436908 nanoseconds spent preparing 1 JDBC statements;
    2585533 nanoseconds spent executing 1 JDBC statements;
    0 nanoseconds spent executing 0 JDBC batches;
    10276363 nanoseconds spent performing 1 L2C puts;
    0 nanoseconds spent performing 0 L2C hits;
    54012289 nanoseconds spent performing 1 L2C misses;
    0 nanoseconds spent executing 0 flushes (flushing a total of 0 entities and 0 collections);
    0 nanoseconds spent executing 0 partial-flushes (flushing a total of 0 entities and 0 collections)
}

And on later requests, something like:

Session Metrics {
    79940 nanoseconds spent acquiring 1 JDBC connections;
    0 nanoseconds spent releasing 0 JDBC connections;
    0 nanoseconds spent preparing 0 JDBC statements;
    0 nanoseconds spent executing 0 JDBC statements;
    0 nanoseconds spent executing 0 JDBC batches;
    0 nanoseconds spent performing 0 L2C puts;
    1665675 nanoseconds spent performing 1 L2C hits;
    0 nanoseconds spent performing 0 L2C misses;
    0 nanoseconds spent executing 0 flushes (flushing a total of 0 entities and 0 collections);
    0 nanoseconds spent executing 0 partial-flushes (flushing a total of 0 entities and 0 collections)
}

Note the cache hit on the second request.

Answer 2

If you see a Hazelcast instance has started there should not be a problem on the caching provider side and L2C must be ready for service. I think the problem is about your entity object. An entity will not be kept in the second level cache unless you use @Cachable annotation for the entity class or define <cache... > in the entity_name.hbm.xml .

Also,

... in this case, does Hibernate cache only the annotated entities?

For the second level cache, yes.

Do you have a recommendation where I should call the statistics?

If you enable the statistics, detailed session stats (seen on Nicolas' answer) will be printed out right after the session is closed.

I think the SQL will always be output by Hibernate, regardless whether the cache activates or not.

No, SQL queries should not show up on the log unless they hit the DB.