Re: [SOLVED] Re: Locking Exception after Persisting new entity

[Daryl Stultz]

On Thu, Nov 12, 2009 at 6:33 AM, Cil-Gamir <[hidden email]> wrote:

> In the past I was using the create method (called save at the time) for
> updating and saving.
>
> I use a single "save" method for create and update. If the object's ID is
null I do a persist. If not null I do a merge. Works fine.

--
Daryl Stultz
_____________________________________
6 Degrees Software and Consulting, Inc.
http://www.6degrees.com
mailto:[hidden email]

[Cil-Gamir]

I thought I had it working, but I was mistaken

It doesn't matter if I merge on update and persist on create. After a persist I cannot do another merge or persist to the database without ending in an optimistic locking exception.

The solution is REALLY simple, I've got one table that doesn't have any relationships to any other tables.

Does anyone have any advice.

[Cil-Gamir]

I've now added a third managed entity, so I am managing three tables now.

All three tables use the same DAO methods to persist objects, the only difference between them are the Entity classes.

One of them works and the other two doesn't.

I've been looking at this for two days now, I have no explanation.

[Daryl Stultz]

On Thu, Nov 12, 2009 at 11:10 AM, Cil-Gamir <[hidden email]>wrote:

>
> I've now added a third managed entity, so I am managing three tables now.
>
> All three tables use the same DAO methods to persist objects, the only
> difference between them are the Entity classes.
>
> One of them works and the other two doesn't.
>

You could start by posting the exception stack. Then your classes with
annotations (or xml) and maybe your DAO code. Also describe how you are
getting entity manager instances and how you are managing the life cycle of
the entity managers.

I doubt I can help you but I think you need to provide more information.

--
Daryl Stultz
_____________________________________
6 Degrees Software and Consulting, Inc.
http://www.6degrees.com
mailto:[hidden email]

[Cil-Gamir]

This is the Exception stack

Exception in thread "main" <openjpa-1.2.1-r752877:753278 fatal store error> org.apache.openjpa.persistence.RollbackException: Optimistic locking errors were detected when flushing to the data store.  The following objects may have been concurrently modified in another transaction: [org.apache.openjpa.enhance.za$co$rmb$rac$riskRatingEngineWeb$entities$Variable$pcsubclass-1081, za.co.rmb.rac.riskRatingEngineWeb.entities.Variable-0]
        at org.apache.openjpa.persistence.EntityManagerImpl.commit(EntityManagerImpl.java:523)
        at za.co.rmb.rac.basicjpadao.DAO.update(DAO.java:41)
        at za.co.rmb.rac.riskRatingEngineWeb.service.VariableService.updateVariable(VariableService.java:24)
        at simpleTest.SimpleTest.updateVariable(SimpleTest.java:168)
        at simpleTest.SimpleTest.doVariables(SimpleTest.java:50)
        at simpleTest.SimpleTest.main(SimpleTest.java:24)
Caused by: <openjpa-1.2.1-r752877:753278 nonfatal store error> org.apache.openjpa.persistence.OptimisticLockException: Optimistic locking errors were detected when flushing to the data store.  The following objects may have been concurrently modified in another transaction: [org.apache.openjpa.enhance.za$co$rmb$rac$riskRatingEngineWeb$entities$Variable$pcsubclass-1081, za.co.rmb.rac.riskRatingEngineWeb.entities.Variable-0]
        at org.apache.openjpa.kernel.BrokerImpl.newFlushException(BrokerImpl.java:2160)
        at org.apache.openjpa.kernel.BrokerImpl.flush(BrokerImpl.java:2010)
        at org.apache.openjpa.kernel.BrokerImpl.flushSafe(BrokerImpl.java:1908)
        at org.apache.openjpa.kernel.BrokerImpl.beforeCompletion(BrokerImpl.java:1826)
        at org.apache.openjpa.kernel.LocalManagedRuntime.commit(LocalManagedRuntime.java:81)
        at org.apache.openjpa.kernel.BrokerImpl.commit(BrokerImpl.java:1350)
        at org.apache.openjpa.kernel.DelegatingBroker.commit(DelegatingBroker.java:877)
        at org.apache.openjpa.persistence.EntityManagerImpl.commit(EntityManagerImpl.java:512)
        ... 5 more
Caused by: <openjpa-1.2.1-r752877:753278 nonfatal store error> org.apache.openjpa.persistence.OptimisticLockException: An optimistic lock violation was detected when flushing object instance "org.apache.openjpa.enhance.za$co$rmb$rac$riskRatingEngineWeb$entities$Variable$pcsubclass-1081" to the data store.  This indicates that the object was concurrently modified in another transaction.
FailedObject: org.apache.openjpa.enhance.za$co$rmb$rac$riskRatingEngineWeb$entities$Variable$pcsubclass@162522b
        at org.apache.openjpa.jdbc.kernel.BatchingPreparedStatementManagerImpl.checkUpdateCount(BatchingPreparedStatementManagerImpl.java:269)
        at org.apache.openjpa.jdbc.kernel.BatchingPreparedStatementManagerImpl.flushBatch(BatchingPreparedStatementManagerImpl.java:189)
        at org.apache.openjpa.jdbc.kernel.BatchingConstraintUpdateManager.flush(BatchingConstraintUpdateManager.java:63)
        at org.apache.openjpa.jdbc.kernel.AbstractUpdateManager.flush(AbstractUpdateManager.java:89)
        at org.apache.openjpa.jdbc.kernel.AbstractUpdateManager.flush(AbstractUpdateManager.java:72)
        at org.apache.openjpa.jdbc.kernel.JDBCStoreManager.flush(JDBCStoreManager.java:717)
        at org.apache.openjpa.kernel.DelegatingStoreManager.flush(DelegatingStoreManager.java:130)
        ... 12 more

[Cil-Gamir]

This is my Entity class

package za.co.rmb.rac.riskRatingEngineWeb.entities;

import java.io.Serializable;
import java.util.Date;
import javax.persistence.Basic;
import javax.persistence.Column;
import javax.persistence.Entity;
import javax.persistence.GeneratedValue;
import javax.persistence.GenerationType;
import javax.persistence.Id;
import javax.persistence.Table;
/**
 *
 * @author jhv
 */
@Entity
@Table(name = "KYC_P2_VARIABLES")
public class Variable implements Serializable {
    private static final long serialVersionUID = 1L;
    @Id
    @GeneratedValue(strategy = GenerationType.IDENTITY)
    @Column(name = "ID")
    private Integer id;
    @Basic(optional = false)
    @Column(name = "NAME")
    private String name;
    @Basic(optional = false)
    @Column(name = "TYPE")
    private String type;
    @Basic(optional = false)
    @Column(name = "VALUE")
    private Double value;
    @Basic(optional = false)
    @Column(name = "START_DATE")
    //@Temporal(TemporalType.TIMESTAMP)
    private Date startDate;
    @Basic(optional = true)
    @Column(name = "END_DATE")
    //@Temporal(TemporalType.TIMESTAMP)
    private Date endDate;
    @Basic(optional = true)
    @Column(name = "USER_NAME")
    private String userName;
    @Basic(optional = false)
    @Column(name = "DESCRIPTION")
    private String description;

.... getters and setters follow, auto generated with netbeans 6.7

[Cil-Gamir]

This is my DAO

package za.co.rmb.rac.basicjpadao;

import java.lang.reflect.Field;
import java.text.SimpleDateFormat;
import java.util.ArrayList;
import java.util.Date;
import java.util.List;
import java.util.Map;
import javax.persistence.EntityManager;
import javax.persistence.Query;
import javax.persistence.Transient;
import org.apache.commons.beanutils.BeanUtils;
import org.apache.commons.beanutils.ConvertUtils;
import org.apache.commons.beanutils.PropertyUtils;
import org.apache.log4j.Logger;

/**
 *
 * @author nico
 */
public abstract class DAO {

    public abstract EntityManager getEntityManager();

    public abstract void setEntityManager(EntityManager entityManager);
    private Logger log = Logger.getLogger(this.getClass());

    public final void create(Object o) {
        getEntityManager().getTransaction().begin();
        getEntityManager().persist(o);
        log.info("############# CREATE START");
        getEntityManager().getTransaction().commit();
        log.info("############# CREATE DONE");        
    }
   
    public final void update(Object o) {
        getEntityManager().getTransaction().begin();
        getEntityManager().merge(o);
        //getEntityManager().flush();
        log.info("############# UPDATE START");
        getEntityManager().getTransaction().commit();
        log.info("############# UPDATE DONE");
    }

[Cil-Gamir]

The DAO Above gets extended by this class

package za.co.rmb.rac.riskRatingEngineWeb.dao;

import java.util.ArrayList;
import java.util.List;

import javax.persistence.EntityManager;
import javax.persistence.OptimisticLockException;
import javax.persistence.Persistence;
import javax.persistence.Query;
import org.apache.log4j.Logger;

import za.co.rmb.rac.basicjpadao.DAO;
import za.co.rmb.rac.riskRatingEngineWeb.entities.Threshold;
import za.co.rmb.rac.riskRatingEngineWeb.entities.Variable;
import za.co.rmb.rac.riskRatingEngineWeb.entities.Regulator;

public class RiskRatingDAO extends DAO {

    private static RiskRatingDAO instance;
    private static Logger log = Logger.getLogger(RiskRatingDAO.class);
    private EntityManager entityManager;
    private Logger logger = Logger.getLogger(this.getClass().getName());

    private RiskRatingDAO() {
    }

    public static RiskRatingDAO getInstance() {
        if (instance == null) {
            instance = new RiskRatingDAO();
        }
        return instance;
    }

    @Override
    public EntityManager getEntityManager() {
        if (entityManager == null) {
            log.info("creating entitymanager");
            entityManager = Persistence.createEntityManagerFactory("risk-rating-data-engine").createEntityManager();
        }
        return entityManager;
    }

    @Override
    public void setEntityManager(EntityManager entityManager) {
        this.entityManager = entityManager;
    }  

[Cil-Gamir]

This is a service class between the front end and the DAO

package za.co.rmb.rac.riskRatingEngineWeb.service;

import java.util.List;
import za.co.rmb.rac.riskRatingEngineWeb.dao.RiskRatingDAO;
import za.co.rmb.rac.riskRatingEngineWeb.entities.Variable;

/**
 *
 * @author JHV
 */
public class VariableService {

    private RiskRatingDAO dao;

    public VariableService() {
        dao = RiskRatingDAO.getInstance();
    }

    public void createVariable(Variable variable) {
        dao.create(variable);
    }

    public void updateVariable(Variable variable) {
        dao.update(variable);
    }

[Cil-Gamir]

This is a test class that shows the error

package simpleTest;

import java.util.Date;
import java.util.List;

import org.apache.log4j.Logger;

import za.co.rmb.rac.riskRatingEngineWeb.entities.Variable;
import za.co.rmb.rac.riskRatingEngineWeb.service.ThresholdService;
import za.co.rmb.rac.riskRatingEngineWeb.service.VariableService;
import za.co.rmb.rac.riskRatingEngineWeb.service.RegulatorService;;

public class SimpleTest {

    private Logger logger = Logger.getLogger(this.getClass().getName());
    private VariableService variableService = new VariableService();

    public static void main(String[] args) {
        SimpleTest st = new SimpleTest();
        st.doVariables();
    }
   
    private void doVariables(){
        Variable v = getVariableOne();
        logger.info("Found variable:");
        logger.info("ID: " + v.getId());
        logger.info("Description: " + v.getDescription());
        logger.info("Value: " + v.getValue());

        // update variable
        v.setValue(v.getValue() + 1);
        logger.info("New Value: " + v.getValue());
        updateVariable(v);

        logger.info("############################################");

        // get the new variable
        v = getVariableTwo();
        logger.info("Found variable:");
        logger.info("ID: " + v.getId());
        logger.info("Description: " + v.getDescription());
        logger.info("Value: " + v.getValue());
        // update variable again
        v.setValue(v.getValue() + 1);
        logger.info("New Value: " + v.getValue());
        updateVariable(v);        
    }


    private Variable getVariableOne() {
        List<Variable> variables = variableService.getVariableByType("TestType", "T1", false);
        if (variables.size() > 1) {
            logger.error("More than one variable fetched");
            System.exit(1);
        }
        return variables.get(0);
    }

    private Variable getVariableTwo() {
        List<Variable> variables = variableService.getVariableByType("TestType", "T3", false);
        if (variables.size() > 1) {
            logger.error("More than one variable fetched");
            System.exit(1);
        }
        return variables.get(0);
    }

   
    public String updateVariable(Variable variable) {
        logger.info("Updating Variable with ID " + variable.getId());

        logger.info("end dating old entity");
        // set the user and end date for the currently active variable
        variable.setEndDate(new Date());
        variable.setUserName("jhv");
        variableService.updateVariable(variable);

          //logger.info("creating new entity");
        Variable v2 = new Variable();
        v2.setDescription(variable.getDescription());
        v2.setStartDate(new Date());
        v2.setName(variable.getName());
        v2.setType(variable.getType());
       v2.setValue(variable.getValue());

        variableService.createVariable(v2);

        return "";
    }

 

}

[Cil-Gamir]

Output of test class before it throws the Exception

2009-11-12 18:21:52,113 INFO  [za.co.rmb.rac.riskRatingEngineWeb.dao.RiskRatingDAO] creating entitymanager
2009-11-12 18:21:53,670 INFO  [simpleTest.SimpleTest] Found variable:
2009-11-12 18:21:53,670 INFO  [simpleTest.SimpleTest] ID: 1081
2009-11-12 18:21:53,670 INFO  [simpleTest.SimpleTest] Description: T1
2009-11-12 18:21:53,670 INFO  [simpleTest.SimpleTest] Value: 27.0
2009-11-12 18:21:53,670 INFO  [simpleTest.SimpleTest] New Value: 28.0
2009-11-12 18:21:53,670 INFO  [simpleTest.SimpleTest] Updating Variable with ID 1081
2009-11-12 18:21:53,670 INFO  [simpleTest.SimpleTest] end dating old entity
2009-11-12 18:21:53,674 INFO  [za.co.rmb.rac.riskRatingEngineWeb.dao.RiskRatingDAO] ############# UPDATE START
2009-11-12 18:21:53,763 INFO  [za.co.rmb.rac.riskRatingEngineWeb.dao.RiskRatingDAO] ############# UPDATE DONE
2009-11-12 18:21:53,766 INFO  [za.co.rmb.rac.riskRatingEngineWeb.dao.RiskRatingDAO] ############# CREATE START
2009-11-12 18:21:53,828 INFO  [za.co.rmb.rac.riskRatingEngineWeb.dao.RiskRatingDAO] ############# CREATE DONE
2009-11-12 18:21:53,828 INFO  [simpleTest.SimpleTest] ############################################
2009-11-12 18:21:53,881 INFO  [simpleTest.SimpleTest] Found variable:
2009-11-12 18:21:53,881 INFO  [simpleTest.SimpleTest] ID: 1078
2009-11-12 18:21:53,881 INFO  [simpleTest.SimpleTest] Description: T3
2009-11-12 18:21:53,881 INFO  [simpleTest.SimpleTest] Value: 11.3
2009-11-12 18:21:53,881 INFO  [simpleTest.SimpleTest] New Value: 12.3
2009-11-12 18:21:53,881 INFO  [simpleTest.SimpleTest] Updating Variable with ID 1078
2009-11-12 18:21:53,881 INFO  [simpleTest.SimpleTest] end dating old entity
2009-11-12 18:21:53,882 INFO  [za.co.rmb.rac.riskRatingEngineWeb.dao.RiskRatingDAO] ############# UPDATE START

[Rick Curtis]

H -

Sorry I haven't processed all of the emails that you sent..... what is the
exact scenario that you having this problem with? Perhaps a few lines of
pseudo code?

I noticed something in one of the emails about pcsubclass.... How are you
enhancing your Entities?

Thanks,
Rick

On Thu, Nov 12, 2009 at 5:09 AM, Cil-Gamir <[hidden email]> wrote:

>
> Hi
>
> I have a situation where I get Optimistic Locking Exceptions when trying to
> persist any object after persisting a new object.
>
> I can persist changes to existing objects as many times as I like, no
> problems.
>
> But as soon as I persist a new object any subsequent persist fails. The
> persist after persisting the new object always fail.
>
> Has anyone seen this before ?
>
> I've been on this for days now.
>
> Thanks
>
> H
> --
> View this message in context:
> http://n2.nabble.com/Locking-Exception-after-Persisting-new-entity-tp3992010p3992010.html
> Sent from the OpenJPA Users mailing list archive at Nabble.com.
>

--
Thanks,
Rick

[Daryl Stultz]

On Thu, Nov 12, 2009 at 11:23 AM, Cil-Gamir <[hidden email]>wrote:

>
> This is the Exception stack
>
> Exception in thread "main" <openjpa-1.2.1-r752877:753278 fatal store error>
> org.apache.openjpa.persistence.RollbackException: Optimistic locking errors
> were detected when flushing to the data store.  The following objects may
> have been concurrently modified in another transaction:
> [org.apache.openjpa.enhance.za
> $co$rmb$rac$riskRatingEngineWeb$entities$Variable$pcsubclass-1081,
> za.co.rmb.rac.riskRatingEngineWeb.entities.Variable-0]
>

The first question "the experts" usually ask is "Are you using build-time or
run-time enhancement?" If you are using run-time as appears to be the case
above, at least to me, try build-time.

--
Daryl Stultz
_____________________________________
6 Degrees Software and Consulting, Inc.
http://www.6degrees.com
mailto:[hidden email]

[Daryl Stultz]

On Thu, Nov 12, 2009 at 11:26 AM, Cil-Gamir <[hidden email]>wrote:

>    @Override
>    public EntityManager getEntityManager() {
>        if (entityManager == null) {
>            log.info("creating entitymanager");
>            entityManager =
>
> Persistence.createEntityManagerFactory("risk-rating-data-engine").createEntityManager();
>        }
>        return entityManager;
>    }
>
>

I see where you are creating your entity manager. Where do you close it?

--
Daryl Stultz
_____________________________________
6 Degrees Software and Consulting, Inc.
http://www.6degrees.com
mailto:[hidden email]

[Cil-Gamir]

Hi Daryl

I'm not closing the entity manager, where should I do this ?

I'm also not familiar with enhancing, my entity classes were declared as final, and JPA complained saying that it cannot do the enhancement for me if my classes are final.

If I want to do the build time enhancement, where is a good place to start to figure out how.

The basic scenario is as follows.

1. I fetch an entity
2. I make a change to that entity and I save it (saving here involves creating a new entity as i'm trying to version rows in the database).
3. I fetch another different entity
4. upon trying to save that entity it fails.

If I only save without persisting a new entity I can do that the whole day. but once I create a new entity the subsequent operation on any other entity or the newly saved one throws an optimistic locking exception

[Cil-Gamir]

I see I can do build time enhancement with Maven2, I'll try that tomorrow and report back

Not at work now

Thanks

H

[Michael Dick]

Hi,

Comments inline

On Thu, Nov 12, 2009 at 11:44 AM, Cil-Gamir <[hidden email]>wrote:

>
> Hi Daryl
>
> I'm not closing the entity manager, where should I do this ?
>

Well, when you're done using it.. From a quick look at your code you cache
the EntityManager in your DAO, but never call the setEntityManager method.
So you get a new instance of the EM each time you call getEntityManager().

I'd suggest updating your main test to cache the em. Something like this :
. . .
EntityManager em = getEntityManager();
em.getTransaction().begin();
em.persist(o);
log.info("############# CREATE START");
em.commit();
em.close();
 . . .
em = getEntityManager()
 . . .

I'd avoid caching it in the DAO for the time being..

> I'm also not familiar with enhancing, my entity classes were declared as
> final, and JPA complained saying that it cannot do the enhancement for me
> if
> my classes are final.
>

<brief aside>
That's a limitation of the subclassing approach to enhancement. If you run
the stand-alone PCEnhancer tool you don't have to worry about final classes
(AFAIK).
</brief aside>


> If I want to do the build time enhancement, where is a good place to start
> to figure out how.
>
>
Here's a good place to start :
http://webspherepersistence.blogspot.com/2009/02/openjpa-enhancement.html

> The basic scenario is as follows.
>
> 1. I fetch an entity
> 2. I make a change to that entity and I save it (saving here involves
> creating a new entity as i'm trying to version rows in the database).
> 3. I fetch another different entity
> 4. upon trying to save that entity it fails.
>
> If I only save without persisting a new entity I can do that the whole day.
> but once I create a new entity the subsequent operation on any other entity
> or the newly saved one throws an optimistic locking exception
> --
> View this message in context:
> http://n2.nabble.com/Re-SOLVED-Re-Locking-Exception-after-Persisting-new-entity-tp3992651p3994474.html
> Sent from the OpenJPA Users mailing list archive at Nabble.com.
>

[Daryl Stultz]

On Thu, Nov 12, 2009 at 12:44 PM, Cil-Gamir <[hidden email]>wrote:

>
> Hi Daryl
>
> I'm not closing the entity manager, where should I do this ?
>

Hard to say. What kind of app are you making? I have a webapp, so I have a
lazy creation mechanism for the em, at the completion of the HTTP request
thread, the EM is closed. So I have one EM per thread that is created and
closed in the lifetime of a single HTTP Request.


>
> I'm also not familiar with enhancing, my entity classes were declared as
> final, and JPA complained saying that it cannot do the enhancement for me
> if
> my classes are final.
>
> If I want to do the build time enhancement, where is a good place to start
> to figure out how.
>

Here's an Ant task that won't work with 1.2.1 if you reference enums:

<target name="EnhanceJPA">
<openjpac>
<classpath path="${classes}" />
<config propertiesFile="${src}/META-INF/persistence.xml"
connectionUserName="user"
connectionPassword="pw"
connectionURL="jdbc:postgresql://localhost/mydb"
connectionDriverName="org.postgresql.Driver" />
<fileset dir=".">
<include name="**/model/*.java" />
</fileset>
</openjpac>
</target>

Here's one that will:

<target name="EnhanceJPA">
<java classname="org.apache.openjpa.enhance.PCEnhancer">
<classpath>
<pathelement path="${classes}"/>
      <pathelement path="${classpath}"/>
      <fileset dir="/path/to/openjpa">
        <include name="**/*.jar"/>
      </fileset>
</classpath>
</java>
</target>


If I only save without persisting a new entity I can do that the whole day.
> but once I create a new entity the subsequent operation on any other entity
> or the newly saved one throws an optimistic locking exception
>

It's possible build time enhancement may take care of this, I don't know,
but you should be doing build-time anyway and depending on your app, closing
the em's.

--
Daryl Stultz
_____________________________________
6 Degrees Software and Consulting, Inc.
http://www.6degrees.com
mailto:[hidden email]

[Cil-Gamir]

Thanks Daryl

I'll try closing the EM, not caching it in the DAO and using built time enhancement.

Will tell U how it goes

H

[Cil-Gamir]

Hi

I think build time enhancement solved it.

I'm getting a different error now

org.apache.openjpa.persistence.EntityExistsException: An object of type "za.co.rmb.rac.riskRatingEngineWeb.entities.Variable" with oid "0" already exists in this context; another cannot be persisted.

But at least the optimistic locking thing has taken a hike

Unfortunately I have a teambuilding thing on today... so I can't fix this thing any further.

Thanks a lot for the help Daryl

Regards

Hannes