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POUpdate all objects in JPA entity
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copied!<p>I'm trying to update all my 4000 Objects in <code>ProfileEntity</code> but I am getting the following exception:</p> <pre><code>javax.persistence.QueryTimeoutException: The datastore operation timed out, or the data was temporarily unavailable. </code></pre> <p>this is my code:</p> <pre><code>public synchronized static void setX4all() { em = EMF.get().createEntityManager(); Query query = em.createQuery("SELECT p FROM ProfileEntity p"); List<ProfileEntity> usersList = query.getResultList(); int a,b,x; for (ProfileEntity profileEntity : usersList) { a = profileEntity.getA(); b = profileEntity.getB(); x = func(a,b); profileEntity.setX(x); em.getTransaction().begin(); em.persist(profileEntity); em.getTransaction().commit(); } em.close(); } </code></pre> <p>I'm guessing that I take too long to query all of the records from <code>ProfileEntity</code>. How should I do it? </p> <ul> <li>I'm using Google App Engine so no UPDATE queries are possible. </li> </ul> <p><strong>Edited 18/10</strong><br> In this 2 days I tried:<br> using Backends as Thanos Makris suggested but got to a dead end. You can see my question <a href="https://stackoverflow.com/questions/12921874/google-app-engine-backend-servlet-not-responding">here</a>.<br> reading DataNucleus suggestion on Map-Reduce but really got lost.</p> <p>I'm looking for a different direction. Since I only going to do this update once, Maybe I can update manually every 200 objects or so.<br> Is it possible to to query for the first 200 objects and after it the second 200 objects and so on?</p>

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