# Cache performance degradation after migration from Hibernate 5.6 \> 6.6

**URL:** <https://discourse.hibernate.org/t/cache-performance-degradation-after-migration-from-hibernate-5-6-6-6/11690>\
**Category:** Hibernate ORM\
**Created:** [July 30, 2025, 3:46pm UTC](https://discourse.hibernate.org/t/cache-performance-degradation-after-migration-from-hibernate-5-6-6-6/11690 "2025-07-30T15:46:20Z")\
**Posts on this page:** 8\
**Page:** 1

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**Author:** ![fedorovstas](https://avatars.discourse-cdn.com/v4/letter/f/a8b319/32.png) [@fedorovstas](https://discourse.hibernate.org/u/fedorovstas)\
**Post date:** [July 30, 2025, 3:46pm UTC](https://discourse.hibernate.org/t/cache-performance-degradation-after-migration-from-hibernate-5-6-6-6/11690/1 "2025-07-30T15:46:20Z")

</div>

Hey, Team

After migrating from **Hibernate 5.6 \> 6.6 version** we faced performance degradation when retrieving data from cache for `JPQL Queries that return a List`, regardless of whether the result is empty or not.

In both Hibernate versions, we use the same version of **Ehcache 3** provider. All other stuff, like Java version, DB version, etc., is the same.

We used **JProfiler** to detect that issue, also we enabled **Hibernate statistics** to be sure that the L2 cache works properly.

We started from Load Tests on our application, but in the simplest variant, we were able to recreate the issue on a simple controller just to run some JPQL Query (that returns a list) in a loop, e.g., with 1000 iterations.

`In the 5.6 query.getResultList() takes ` **`30-50`** ` nanoseconds`

`In the 6.6 query.getResultList() takes ` **`300-500`** ` nanoseconds`  
**`This is 10 times slower`**

For query.getSingleResult(), I have not faced the above behavior.

Is there any explanation for such performance degradation?  
Let me know if you need some additional data from our side.

Thank you!

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<div class="post-metadata">

**Author:** ![beikov](https://yyz1.discourse-cdn.com/flex035/user_avatar/discourse.hibernate.org/beikov/32/258_2.png) [@beikov](https://discourse.hibernate.org/u/beikov)\
**Post date:** [July 31, 2025, 7:39am UTC](https://discourse.hibernate.org/t/cache-performance-degradation-after-migration-from-hibernate-5-6-6-6/11690/2 "2025-07-31T07:39:41Z")

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We have a [bunch of benchmarks](https://github.com/hibernate/hibernate-orm-benchmark/tree/main) that we used to verify the performance of Hibernate ORM 6, but I haven’t seen such a slowdown before.

If you want us to look into it, I would suggest you to maybe create a PR against that hibernate-orm-benchmarks repository that reproduces the problem.

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<div class="post-metadata">

**Author:** ![fedorovstas](https://avatars.discourse-cdn.com/v4/letter/f/a8b319/32.png) [@fedorovstas](https://discourse.hibernate.org/u/fedorovstas)\
**Post date:** [August 1, 2025, 7:39am UTC](https://discourse.hibernate.org/t/cache-performance-degradation-after-migration-from-hibernate-5-6-6-6/11690/3 "2025-08-01T07:39:02Z")

</div>

Hello,

I was able to recreate this performance issue in [test case template](https://github.com/hibernate/hibernate-test-case-templates/blob/master/orm/hibernate-orm-7/src/test/java/org/hibernate/bugs/JPAUnitTestCase.java) .

On the “test case template, the JProfiler shows that in **6.6** , the fetch operation from the query cache for the query.getResultList() performs **2 times slower** than in the **5.6** version.

In the UnitTest the overall difference ~50%, but it is difficult to isolate only the fetch from cache operation.

On my project, the difference is **10 times slower**.

The steps to recreate:

1. Use Jcache and Ehcache
2. Enable L2 cache and query caching
3. Create a simple Entity
4. In the test method, persist this entity and then fetch it in the query in the loop (e.g. 10k times)

Here are my classes/methods. I hope this will help to recreate the issue:

```auto
@Entity
@Cacheable
public class Department {

    @Id
    @GeneratedValue(strategy = GenerationType.IDENTITY)
    private Long id;

    private String name;

    // Getters and Setters
    public Long getId() {
        return id;
    }

    public void setId(Long id) {
        this.id = id;
    }

    public String getName() {
        return name;
    }

    public void setName(String name) {
        this.name = name;
    }

}

```

```auto
@Test
void hhh123Test() throws Exception {
   EntityManager entityManager = entityManagerFactory.createEntityManager();
   entityManager.getTransaction().begin();

   Department department = new Department();;
   department.setName("name");
   entityManager.persist(department);
   entityManager.getTransaction().commit();

   entityManager.getTransaction().begin();
   long startTime = System.currentTimeMillis();

   for (int i = 1; i <= 10000; i++) {
      List<Department> departments = readAllDepartments(entityManager);
   }

   long endTime = System.currentTimeMillis();
   long timeElapsed = endTime - startTime;

   System.out.println("timeElapsed: " + timeElapsed);
   entityManager.getTransaction().commit();

   entityManager.close();
}

public List<Department> readAllDepartments(EntityManager entityManager) {

   TypedQuery<Department> query = entityManager.createQuery(
         "SELECT d FROM Department d",
         Department.class
   );

   query.setHint(QueryHints.HINT_CACHEABLE, true);
   query.setHint(QueryHints.HINT_CACHE_REGION, "query.Department");

   return query.getResultList();
}

```

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<div class="post-metadata">

**Author:** ![beikov](https://yyz1.discourse-cdn.com/flex035/user_avatar/discourse.hibernate.org/beikov/32/258_2.png) [@beikov](https://discourse.hibernate.org/u/beikov)\
**Post date:** [August 1, 2025, 9:12am UTC](https://discourse.hibernate.org/t/cache-performance-degradation-after-migration-from-hibernate-5-6-6-6/11690/4 "2025-08-01T09:12:27Z")

</div>

We have benchmarks that exercise the query cache with an entity that even contains an association: [hibernate-orm-benchmark/basic/src/test/java/org/hibernate/benchmark/queryl2hit/QueryCacheEntityWithAssociation.java at main · hibernate/hibernate-orm-benchmark · GitHub](https://github.com/hibernate/hibernate-orm-benchmark/blob/main/basic/src/test/java/org/hibernate/benchmark/queryl2hit/QueryCacheEntityWithAssociation.java)

If you can reproduce the problem with a similar benchmark, please open a PR against that repo and then we will look into it.

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<div class="post-metadata">

**Author:** ![fedorovstas](https://avatars.discourse-cdn.com/v4/letter/f/a8b319/32.png) [@fedorovstas](https://discourse.hibernate.org/u/fedorovstas)\
**Post date:** [March 16, 2026, 11:28am UTC](https://discourse.hibernate.org/t/cache-performance-degradation-after-migration-from-hibernate-5-6-6-6/11690/5 "2026-03-16T11:28:36Z")

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Hi, Team! (cc:@beikov)

We came back to the performance tests for our application after  
Hibernate 5.6.15 \> Hibernate 7.2.7 migration.

We used the project/test that you suggested  
[hibernate-orm-benchmark/basic/src/test/java/org/hibernate/benchmark/queryl2hit/QueryCacheEntityWithAssociation.java at main · hibernate/hibernate-orm-benchmark · GitHub](https://github.com/hibernate/hibernate-orm-benchmark/blob/main/basic/src/test/java/org/hibernate/benchmark/queryl2hit/QueryCacheEntityWithAssociation.java)

And the results are the same as we had for the 5.6.15 \> 6.6.x migration half a year ago:

> 50% performance degradation for getResultList() operation for cached entity

> On our real data, the performance degradation for such operations is up to 400%

I don’t have the permissions to create a PR in that repo, but my code changes are super straightforward.

1. Increased the count of iterations from 1000 to 10000 - to be more precise
2. Added “Time elapsed” only for the loop where call getResultList() - to isolate the getResultList() operation

Here is the 'Time elapsed" for 5.6.x, 6.6.x, 7.2.x Hibernate versions

**5.6.15**

> Time elapsed: 125  
> Time elapsed: 68  
> Time elapsed: 57  
> Time elapsed: 54  
> Time elapsed: 47

**6.6.44**

> Time elapsed: 200  
> Time elapsed: 106  
> Time elapsed: 92  
> Time elapsed: 80  
> Time elapsed: 75

**7.2.7**

> Time elapsed: 229  
> Time elapsed: 105  
> Time elapsed: 88  
> Time elapsed: 80  
> Time elapsed: 75

```auto
@Benchmark
public void single(Blackhole bh, EventCounters counters) {
    em = entityManagerFactory.createEntityManager();
    em.getTransaction().begin();
    final Author author = em.createQuery( "from Author", Author.class ).setMaxResults( 1 ).getSingleResult();
       //add start time
       long startTime = System.currentTimeMillis();
       //increase count of iterations to 10000
       for (int i = 0; i < 10000; i++) {
       final List<Book> books = em.createQuery( "from Book b where b.author = :author", Book.class )
             .setParameter( "author", author )
             .setHint( "org.hibernate.cacheable", "true" )
             .getResultList();
       for ( Book book : books ) {
          if ( bh != null ) {
             bh.consume( book );
          }
       }
       if ( counters != null ) {
          counters.books += books.size();
       }
    }
       long endTime = System.currentTimeMillis();
       long timeElapsed = endTime - startTime;
       //show Time elapsed
       System.out.println("Time elapsed: " + timeElapsed);
    em.getTransaction().commit();
    em.close();
}

```

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<div class="post-metadata">

**Author:** ![beikov](https://yyz1.discourse-cdn.com/flex035/user_avatar/discourse.hibernate.org/beikov/32/258_2.png) [@beikov](https://discourse.hibernate.org/u/beikov)\
**Post date:** [March 16, 2026, 1:37pm UTC](https://discourse.hibernate.org/t/cache-performance-degradation-after-migration-from-hibernate-5-6-6-6/11690/6 "2026-03-16T13:37:58Z")

</div>

Maybe @mbladel wants to look into that as he recently worked on some caching related bug fixes. Some degradation is certainly possible, because Hibernate ORM 6 does more than ORM 5 in terms of fetching and has other defaults, but I agree that this looks a bit odd.

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<div class="post-metadata">

**Author:** ![fedorovstas](https://avatars.discourse-cdn.com/v4/letter/f/a8b319/32.png) [@fedorovstas](https://discourse.hibernate.org/u/fedorovstas)\
**Post date:** [March 16, 2026, 3:13pm UTC](https://discourse.hibernate.org/t/cache-performance-degradation-after-migration-from-hibernate-5-6-6-6/11690/7 "2026-03-16T15:13:06Z")

</div>

You mentioned that  
`"and has other defaults"`

Any suggestions on what we can change to make 6.x defaults similar to 5.x version?

Thank you

---

<div class="post-metadata">

**Author:** ![beikov](https://yyz1.discourse-cdn.com/flex035/user_avatar/discourse.hibernate.org/beikov/32/258_2.png) [@beikov](https://discourse.hibernate.org/u/beikov)\
**Post date:** [March 16, 2026, 3:53pm UTC](https://discourse.hibernate.org/t/cache-performance-degradation-after-migration-from-hibernate-5-6-6-6/11690/8 "2026-03-16T15:53:17Z")

</div>

Well, Hibernate ORM 5 and before by default behaved as if you configure `hibernate.cache.query_cache_layout=shallow`: [Hibernate ORM User Guide](https://docs.hibernate.org/orm/7.2/userguide/html_single/#caching-query-cache-layout)

But then Hibernate ORM 6+ will also fetch data according to the configured laziness of the entity class, even if data is not in the cache. I believe ORM 5 just took what was there and you could end up with `LazyInitializationException` later. I don’t know your exact model, but I would suggest you to print the SQL queries that are executed as well to see if more queries are being executed with Hibernate ORM 6+.