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POJPA / Eclipselink @Cache expiry ignored
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    copied!<p>I'm currently evaluating JPA/Eclipselink as an alternative to our current very ugly jdbc database access. The situation is the following:</p> <p>Multiple clients access the same database and sometimes edit the same data. This data should be refreshed regularly and only be cached for a short period of time. From my understanding the @Cache annotation should exactly do that.</p> <p>The following code is based on the jpa/eclipselink on <a href="http://www.vogella.com/articles/JavaPersistenceAPI/article.html" rel="nofollow">Vogella</a></p> <pre><code>@Entity @Cache(expiry = 100) public class Todo { @Id @GeneratedValue(strategy = GenerationType.IDENTITY) private Long id; private String summary; private String description; ... getter/setter/toString omited } public static void main(String[] args) throws InterruptedException { EntityManagerFactory factory = Persistence.createEntityManagerFactory("mysql"); EntityManager em = factory.createEntityManager(); TypedQuery&lt;Todo&gt; q = em.createQuery("SELECT t FROM Todo t", Todo.class); List&lt;Todo&gt; todoList = q.getResultList(); System.out.println("Query 1 read"); for (int i = 0; i &lt; todoList.size(); i++) { System.out.println("1: " + todoList.get(i)); } Thread.sleep(30000); TypedQuery&lt;Todo&gt; q2 = em.createQuery("SELECT t FROM Todo t", Todo.class); // q2.setHint("javax.persistence.cache.storeMode", "REFRESH"); List&lt;Todo&gt; todoList2 = q2.getResultList(); System.out.println("Query 2 read"); for (int i = 0; i &lt; todoList.size(); i++) { System.out.println("1: " + todoList.get(i)); System.out.println("2: " + todoList2.get(i)); System.out.println(todoList.get(i) == todoList2.get(i)); } } &lt;?xml version="1.0" encoding="UTF-8"?&gt; &lt;persistence version="2.0" xmlns="http://java.sun.com/xml/ns/persistence" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation="http://java.sun.com/xml/ns/persistence http://java.sun.com/xml/ns/persistence/persistence_2_0.xsd"&gt; &lt;persistence-unit name="mysql" transaction-type="RESOURCE_LOCAL"&gt; &lt;provider&gt;org.eclipse.persistence.jpa.PersistenceProvider&lt;/provider&gt; &lt;exclude-unlisted-classes&gt;false&lt;/exclude-unlisted-classes&gt; &lt;properties&gt; &lt;property name="javax.persistence.jdbc.password" value="" /&gt; &lt;property name="javax.persistence.jdbc.user" value="root" /&gt; &lt;property name="javax.persistence.jdbc.driver" value="com.mysql.jdbc.Driver" /&gt; &lt;property name="javax.persistence.jdbc.url" value="jdbc:mysql://localhost:3306/test" /&gt; &lt;property name="javax.persistence.ddl-generation" value="create-tables" /&gt; &lt;property name="javax.persistence.logging.level" value="ALL" /&gt; &lt;property name="eclipselink.logging.level" value="ALL"/&gt; &lt;/properties&gt; &lt;/persistence-unit&gt; &lt;/persistence&gt; </code></pre> <p>Running the Programm produces the following output:</p> <pre><code>... [EL Finest]: query: 2013-06-19 14:30:55.897--UnitOfWork(31211079)--Thread(Thread[main,5,main])--Execute query ReadAllQuery(referenceClass=Todo sql="SELECT ID, DESCRIPTION, SUMMARY FROM TODO") [EL Finest]: connection: 2013-06-19 14:30:55.907--ServerSession(7427424)--Connection(7633596)--Thread(Thread[main,5,main])--Connection acquired from connection pool [default]. [EL Fine]: sql: 2013-06-19 14:30:55.907--ServerSession(7427424)--Connection(7633596)--Thread(Thread[main,5,main])--SELECT ID, DESCRIPTION, SUMMARY FROM TODO [EL Finest]: connection: 2013-06-19 14:30:55.924--ServerSession(7427424)--Connection(7633596)--Thread(Thread[main,5,main])--Connection released to connection pool [default]. Query 1 read 1: Todo [id=1, summary=s1, description=d1] 1: Todo [id=2, summary=qwet, description=d2] [EL Finest]: query: 2013-06-19 14:31:25.932--UnitOfWork(31211079)--Thread(Thread[main,5,main])--Execute query ReadAllQuery(referenceClass=Todo sql="SELECT ID, DESCRIPTION, SUMMARY FROM TODO") [EL Finest]: connection: 2013-06-19 14:31:25.932--ServerSession(7427424)--Connection(7633596)--Thread(Thread[main,5,main])--Connection acquired from connection pool [default]. [EL Fine]: sql: 2013-06-19 14:31:25.932--ServerSession(7427424)--Connection(7633596)--Thread(Thread[main,5,main])--SELECT ID, DESCRIPTION, SUMMARY FROM TODO [EL Finest]: connection: 2013-06-19 14:31:25.934--ServerSession(7427424)--Connection(7633596)--Thread(Thread[main,5,main])--Connection released to connection pool [default]. Query 2 read 1: Todo [id=1, summary=s1, description=d1] 2: Todo [id=1, summary=s1, description=d1] true 1: Todo [id=2, summary=qwet, description=d2] 2: Todo [id=2, summary=qwet, description=d2] true </code></pre> <p>While the Thread sleeps I change a value in the database. I would expect to get the new value from the database, because the value in the cache should have been expired. It seems the code simply ignores the @Cache annotation. I also tried various other settings like type=CacheType.NONE und alwaysRefresh=true, but none did change anything.</p> <p>When I add the storeMode-QueryHint, the query always refreshes the result. This is not exactly what I want and it seems I need to add it to each query which is quite error prone. But it is still strange that the Cache annotation is ignored.</p> <p>I also tried to use a DescriptorCustomizer, but it also has no effect, despite being used (tested with a breakpoint).</p> <pre><code>public void customize(ClassDescriptor descriptor) { descriptor.alwaysRefreshCache(); descriptor.alwaysRefreshCacheOnRemote(); descriptor.disableCacheHits(); descriptor.disableCacheHitsOnRemote(); } </code></pre> <p>Update:</p> <p>Some words to the system I'm developing. It's module to read/write our master data. Therefore, it feels wrong to have, for example, an User-object twice in memory for the same user. Also after I tested the @ReadOnly annotation I noticed that the isolation-parameter of the @Cache annotation seems to work, but still nothing about the expire, alwaysrefresh, etc.</p>
 

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