Disable caching in JPA (eclipselink)

spring boot jpa disable cache
jpa clear cache
jpa entitymanager disable cache
eclipselink shared cache
eclipselink shared-cache-mode
eclipselink cache
jpa cache
java persistence disable cache

I want to use JPA (eclipselink) to get data from my database. The database is changed by a number of other sources and I therefore want to go back to the database for every find I execute. I have read a number of posts on disabling the cache but this does not seem to be working. Any ideas?

I am trying to execute the following code:

        EntityManagerFactory entityManagerFactory =  Persistence.createEntityManagerFactory("default");
        EntityManager em = entityManagerFactory.createEntityManager();

        MyLocation one = em.createNamedQuery("MyLocation.findMyLoc").getResultList().get(0);

        MyLocation two = em.createNamedQuery("MyLocation.findMyLoc").getResultList().get(0);    

        System.out.println(one==two);

one==two is true while I want it to be false.

I have tried adding each/all the following to my persistence.xml

<property name="eclipselink.cache.shared.default" value="false"/>
<property name="eclipselink.cache.size.default" value="0"/>
<property name="eclipselink.cache.type.default" value="None"/>

I have also tried adding the @Cache annotation to the Entity itself:

@Cache(
  type=CacheType.NONE, // Cache nothing
  expiry=0,
  alwaysRefresh=true
)

Am I misunderstanding something?

This behavior is correct, otherwise if you change object one and object two with different values you will have problems when persisting them. What is happening is the call to load object two updates the entity loaded in the first call. They must point to the same object since they ARE the same object. This ensures that dirty data cannot be written.

If you call em.clear() between the two calls, entity one should become detached your check will return false. There is however no need to do that, eclipse link is infact updating your data to the latest which I would guess is what you want since it frequently changes.

On a side note if you wish to update this data using JPA you will need to be obtaining pessimistic locks on the Entity so that the underlying data cannot change in the DB.

You will need to disable the query cache as well your cache options were just removing the object cache from play not the query cache, that is why you are not getting the new results:

In your code:

em.createNamedQuery("MyLocation.findMyLoc").setHint(QueryHints.CACHE_USAGE, CacheUsage.DoNotCheckCache).getResultList().get(0);

Or in persistence.xml:

<property name="eclipselink.query-results-cache" value="false"/>

Disable caching in JPA (eclipselink), Note, the CacheType NONE on the @Cache annotation should not be used to disable the cache, instead shared should be set to false. Or in JPA 2.0 using the @Cacheable annotation. EclipseLink also offers several different caching strategies, the configure how many objects are cached, and how much memory is used. Note, the CacheType NONE on the @Cache annotation should not be used to disable the cache, instead shared should be set to false.

final Query readQuery = this.entityManager.createQuery(selectQuery);
readQuery.setParameter(paramA, valueA);

// Update the JPA session cache with objects that the query returns.
// Hence the entity objects in the returned collection always updated.
readQuery.setHint(QueryHints.REFRESH, HintValues.TRUE);

entityList = readQuery.getResultList();

This works for me.

EclipseLink/Examples/JPA/Caching - Eclipsepedia, JPA 2.0 defines the concept of a shared cache. The @Cacheable annotation or cacheable XML attribute can be used to enable or disable caching on a class. Do not disable the cache by setting the CacheType to None, this can cause object identity issues. See, Caching Example and the Caching section of the EclipseLink JPA User Guide for more information on caching.

If you wish to disable caching without getting vendor specific, you could annotate your domain object with:

@Cacheable(false)

Here is an example:

@Entity
@Table(name="SomeEntity")
@Cacheable(false)
public class SomeEntity {
    // ...
}

Java Persistence/Caching, 可以将文章内容翻译成中文,广告屏蔽插件可能会导致该功能失效(如失效,请关闭广告屏蔽插件后再试):. 问题: I want to use JPA (eclipselink) to get� The EclipseLink caching Architecture is shown below. Support for second level cache in EclipseLink is turned on by default, entities read are L2 cached. You can disable the L2 cache. EclipseLink

See,

http://wiki.eclipse.org/EclipseLink/UserGuide/JPA/Basic_JPA_Development/Caching

For the same EntityManager JPA always requires that one==two, so this is correct, not matter your caching options (this is the L1 cache, or transactional cache, which enforces your transaction isolation and maintains object identity).

To force the query to refresh (and revert any changes you have made) you can use the query hint "eclipselink.refresh"="true". Or probably better, use a new EntityManager for each query/request, or call clear() on your EntityManager.

<property name="eclipselink.cache.shared.default" value="false"/>

Is the correct way to disable the shared cache (L2 cache). Please remove all your other settings as they are not correct, and can cause issues.

EclipseLink does not maintain a query cache by default, so those settings will have no affect. CacheUsage is also not correct, do not use this (it is for in-memory querying).

Disable caching in JPA (eclipselink), Hello, We were using hibernate ORM, we want disable the first-level cache, but We didn't find any way. How to disable the first-level cache? Thanks, EclipseLink also provides a number of persistence unit properties that you can specify to configure the EclipseLink cache. These properties may compliment or provide an alternative to annotations. For a list of these properties, see "Caching" in Java Persistence API (JPA) Extensions Reference for EclipseLink .

If manually modifying the attributes of the object, for example MyLocation. The above trick (CACHE_USAGE=CacheUsage.DoNotCheckCache, or eclipselink.query-results-cache=false) does not seem to work as I tried.

So i tried to set another hint which is eclipselink.refresh, to true. then it works. I mean the manually changed attributes get retrieved.

So as i understand, the above trick only ensure the it gets the correct objects. However, if the objects have been cached already, eclipselink just returns them without checking the freshness of the contents of the objects. Only when the hint eclipselink.refresh is set to true, will these objects get refreshed to reflect the latest attribute values.

How to disable the first-level cache with JPA and Hibernate , The EclipseLink cache is an in-memory repository that stores recently read or written For a list of these properties, see "Caching" in Java Persistence API ( JPA) The @Noncacheable annotation can also be used to disable caching of a � The EclipseLink JPA persistence provider caching Architecture The EclipseLink caching Architecture is shown below. Support for second level cache in EclipseLink is turned on by default, entities

Understanding Caching, The EclipseLink cache is an in-memory repository that stores recently read or see Oracle Fusion Middleware Java Persistence API (JPA) Extensions Reference for The @Noncacheable annotation can also be used to disable caching of a� 9 Understanding Caching. The EclipseLink cache is an in-memory repository that stores recently read or written objects based on class and primary key values. The cache improves performance by holding recently read or written objects and accessing them in-memory to minimize database access, manage locking and isolation level, and manage object identity.

9 Understanding Caching, To adjust the cache mode settings for a persistence unit, specify one of the cache transaction-type="JTA"> <provider>org.eclipse.persistence.jpa. <shared- cache-mode>DISABLE_SELECTIVE</shared-cache-mode> </persistence-unit> � Caching is an important performance improvement technique. JPA supports caching of object data. In this chapter we are looking into the caching techniques available with JPA for caching object data. JPA Caching. JPA supports two levels of caching. They are 1)Level 1 Cache 2)Level 2 Cache. We will be looking these caching techniques in detail.

Specifying the Cache Mode Settings to Improve Performance, Setting Up Cache JPA Coordination with the Payara Platform using EclipseLink Cache entity annotation (EclipseLink proprietary, use as a last resort) DISABLE_SELECTIVE, Try to Cache all entities, except those selected� EclipseLink SDO provides Data Access Service (DAS) combining existing POJO object models or JPA entities wrapped within static or dynamic data objects. Try it. This example provides a simple RCP application that uses EclipseLink JPA.

Comments
  • James in your comment to my answer, was the caching off ( <property name="eclipselink.cache.shared.default" value="false"/> ) when you tested it?
  • Sorry just noticed this, yes the caching was off. I am still having this issue and am no closer to a solution.
  • That helps thank you. I will have to look at pessimistic locks as the data will be changing. How then if I add a Thread.sleep(10000) between the queries and in that time manually change an attribute of MyLocation in the database does two (and therefore one) not reflect this change?
  • added a link to some info about pessimistic locks
  • I have tried the described change in the code and persistence.xml and still don't get the value I changed directly. Any ideas?
  • Have a look at your transaction isolation levels. If your transactions use Serializable as isolation levels (default in Oracle for example), than T1 will never see changes from T2 (AFAIK).
  • DoNotCheckCache will make sure the cache won't be cached. Is it possible to make sure that the returned entity by that query is not cached ?
  • This should be definitely the valid answer !
  • Note that "eclipselink.refresh"="true" is buggy in current versions of EclipseLink (bugs.eclipse.org/bugs/show_bug.cgi?id=398074); also, it is EclipseLink-specific and not part of JPA. So I'd advise to just get a fresh EntityManager whenever you want fresh data - that's how it is supposed to work with JPA.
  • Getting a fresh EntityManager will not get you a fresh object directly from the database. The cache work on a EntityManagerFactory level, which normally has the life time of the application.
  • Hava you set this in your persistence.xml? If I add this hint to the query it works. But it does not work if I define it only in my persistence.xml.
  • The refresh hint mentioned above did not work for you?
  • I didn't try that, because I wanted to bypass jpa cache just in some queries.