问题
I have a java project that runs on a webserver. I always hit this exception.
I read some documentation, and found that pessimistic locking (or optimistic, but I read that pessimistic is better) is the best way to prevent this exception.
But I couldn't find any clear example that explains how to use it.
My method is like:
@Transactional
Public void test(Email email, String Subject){
getEmailById(String id);
email.setSubject(Subject);
updateEmail(email);
}
while:
Emailis a hibernate class (it will be a table in the database)getEmailById(String id)is a function that returns anemail(this method is not annotated with@Transctional)updateEmail(email): is a method that updates the email.
Note: I use hibernate for save, update & so on (example: session.getcurrentSession.save(email))
The exception:
ERROR 2011-12-21 15:29:24,910 Could not synchronize database state with session [myScheduler-1]
org.hibernate.StaleObjectStateException: Row was updated or deleted by another transaction (or unsaved-value mapping was incorrect): [email#21]
at org.hibernate.persister.entity.AbstractEntityPersister.check(AbstractEntityPersister.java:1792)
at org.hibernate.persister.entity.AbstractEntityPersister.update(AbstractEntityPersister.java:2435)
at org.hibernate.persister.entity.AbstractEntityPersister.updateOrInsert(AbstractEntityPersister.java:2335)
at org.hibernate.persister.entity.AbstractEntityPersister.update(AbstractEntityPersister.java:2635)
at org.hibernate.action.EntityUpdateAction.execute(EntityUpdateAction.java:115)
at org.hibernate.engine.ActionQueue.execute(ActionQueue.java:279)
at org.hibernate.engine.ActionQueue.executeActions(ActionQueue.java:263)
at org.hibernate.engine.ActionQueue.executeActions(ActionQueue.java:168)
at org.hibernate.event.def.AbstractFlushingEventListener.performExecutions(AbstractFlushingEventListener.java:321)
at org.hibernate.event.def.DefaultFlushEventListener.onFlush(DefaultFlushEventListener.java:50)
at org.hibernate.impl.SessionImpl.flush(SessionImpl.java:1027)
at org.hibernate.impl.SessionImpl.managedFlush(SessionImpl.java:365)
at org.hibernate.transaction.JDBCTransaction.commit(JDBCTransaction.java:137)
at org.springframework.orm.hibernate3.HibernateTransactionManager.doCommit(HibernateTransactionManager.java:656)
at org.springframework.transaction.support.AbstractPlatformTransactionManager.processCommit(AbstractPlatformTransactionManager.java:754)
at org.springframework.transaction.support.AbstractPlatformTransactionManager.commit(AbstractPlatformTransactionManager.java:723)
at org.springframework.transaction.interceptor.TransactionAspectSupport.commitTransactionAfterReturning(TransactionAspectSupport.java:393)
at org.springframework.transaction.interceptor.TransactionInterceptor.invoke(TransactionInterceptor.java:120)
at org.springframework.aop.framework.ReflectiveMethodInvocation.proceed(ReflectiveMethodInvocation.java:172)
at org.springframework.aop.framework.JdkDynamicAopProxy.invoke(JdkDynamicAopProxy.java:202)
at $Proxy130.generateEmail(Unknown Source)
at com.admtel.appserver.tasks.EmailSender.run(EmailNotificationSender.java:33)
at com.admtel.appserver.tasks.EmailSender$$FastClassByCGLIB$$ea0d4fc2.invoke(<generated>)
at net.sf.cglib.proxy.MethodProxy.invoke(MethodProxy.java:149)
at org.springframework.aop.framework.Cglib2AopProxy$CglibMethodInvocation.invokeJoinpoint(Cglib2AopProxy.java:688)
at org.springframework.aop.framework.ReflectiveMethodInvocation.proceed(ReflectiveMethodInvocation.java:150)
at org.springframework.aop.aspectj.AspectJAfterThrowingAdvice.invoke(AspectJAfterThrowingAdvice.java:55)
at org.springframework.aop.framework.ReflectiveMethodInvocation.proceed(ReflectiveMethodInvocation.java:161)
at org.springframework.aop.framework.adapter.AfterReturningAdviceInterceptor.invoke(AfterReturningAdviceInterceptor.java:50)
at org.springframework.aop.framework.ReflectiveMethodInvocation.proceed(ReflectiveMethodInvocation.java:161)
at org.springframework.aop.framework.adapter.MethodBeforeAdviceInterceptor.invoke(MethodBeforeAdviceInterceptor.java:50)
at org.springframework.aop.framework.ReflectiveMethodInvocation.proceed(ReflectiveMethodInvocation.java:161)
at org.springframework.aop.interceptor.ExposeInvocationInterceptor.invoke(ExposeInvocationInterceptor.java:89)
at org.springframework.aop.framework.ReflectiveMethodInvocation.proceed(ReflectiveMethodInvocation.java:172)
at org.springframework.aop.framework.Cglib2AopProxy$DynamicAdvisedInterceptor.intercept(Cglib2AopProxy.java:621)
at com.admtel.appserver.tasks.EmailNotificationSender$$EnhancerByCGLIB$$33eb7303.run(<generated>)
at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:39)
at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:25)
at java.lang.reflect.Method.invoke(Method.java:597)
at org.springframework.util.MethodInvoker.invoke(MethodInvoker.java:273)
at org.springframework.scheduling.support.MethodInvokingRunnable.run(MethodInvokingRunnable.java:65)
at org.springframework.scheduling.support.DelegatingErrorHandlingRunnable.run(DelegatingErrorHandlingRunnable.java:51)
at java.util.concurrent.Executors$RunnableAdapter.call(Executors.java:441)
at java.util.concurrent.FutureTask$Sync.innerRunAndReset(FutureTask.java:317)
at java.util.concurrent.FutureTask.runAndReset(FutureTask.java:150)
at java.util.concurrent.ScheduledThreadPoolExecutor$ScheduledFutureTask.access$101(ScheduledThreadPoolExecutor.java:98)
at java.util.concurrent.ScheduledThreadPoolExecutor$ScheduledFutureTask.runPeriodic(ScheduledThreadPoolExecutor.java:180)
at java.util.concurrent.ScheduledThreadPoolExecutor$ScheduledFutureTask.run(ScheduledThreadPoolExecutor.java:204)
at java.util.concurrent.ThreadPoolExecutor$Worker.runTask(ThreadPoolExecutor.java:886)
at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:908)
at java.lang.Thread.run(Thread.java:680)
ERROR 2011-12-21 15:29:24,915 [ exception thrown < EmailNotificationSender.run() > exception message Object of class [Email] with identifier [211]: optimistic locking failed; nested exception is org.hibernate.StaleObjectStateException: Row was updated or deleted by another transaction (or unsaved-value mapping was incorrect): [Email#21] with params ] [myScheduler-1]
org.springframework.orm.hibernate3.HibernateOptimisticLockingFailureException: Object of class [Email] with identifier [21]: optimistic locking failed; nested exception is
回答1:
Pessimistic locking is generally not recommended and it's very costly in terms of performance on database side. The problem that you have mentioned (the code part) a few things are not clear such as:
- If your code is being accessed by multiple threads at the same time.
- How are you creating
sessionobject (not sure if you are using Spring)?
Hibernate Session objects are NOT thread-safe. So if there are multiple threads accessing the same session and trying to update the same database entity, your code can potentially end up in an error situation like this.
So what happens here is that more than one thread tries to update the same entity, one thread succeeds and when the next thread goes to commit the data, it sees that its already been modified and ends up throwing StaleObjectStateException.
EDIT:
There is a way to use Pessimistic Locking in Hibernate. Check out this link. But there seems to be some issue with this mechanism. I came across posting a bug in hibernate (HHH-5275), however. The scenario mentioned in the bug is as follows:
Two threads are reading the same database record; one of those threads should use pessimistic locking thereby blocking the other thread. But both threads can read the database record causing the test to fail.
This is very close to what you are facing. Please try this if this does not work, the only way I can think of is using Native SQL queries where you can achieve pessimistic locking in postgres database with SELECT FOR UPDATE query.
回答2:
It doesn't appear that you are actually using the email that you retrieve from the database, but an older copy that you get as a parameter. Whatever is being used for version control on the row has changed between when the previous version was retrieved and when you are doing the update.
You probably want your code to look more like:
@Transactional
Public void test(String id, String subject){
Email email = getEmailById(id);
email.setSubject(subject);
updateEmail(email);
}
回答3:
I know this is an old question, but some of us are still hitting it and look at sky wandering how. Here is one kind of issue that I faced,
We have a queue manager that polls data and give to handlers for processing. To avoid picking up the same events again, the queue manger locks the record in database with a LOCKED state.
void poll() {
record = dao.getLockedEntity();
queue(record);
}
this method wasn't transactional but dao.getLockedEntity() was transactional with 'REQUIRED'.
All good and on the road, after few months in production, it failed with optimistic locking exception,
After lots of debugging and checking in details we could find out that some one has changed the code like this,
@Transactional(propagation=Propagation.REQUIRED, readOnly=false)
void poll() {
record = dao.getLockedEntity();
queue(record);
}
So the record was queued even before the transaction in dao.getLockedEntity() get committed (it uses the same transaction of poll method) and the object was changed underneath by the handlers (different threads) by the time the poll() method transaction get comitted.
We fixed the issue and it looks good now.
I thought of sharing it, because optimistic lock exception can be confusing and are difficult to debug. Some one might get benefited from my experience.
Regards Lyju
回答4:
This exception is probably caused by optimistic locking (or by a bug in your code). You're probably using it without knowing. And your pseudo-code (which should be replaced by real code to be able to diagnose the problem) is wrong. Hibernate saves all the modifications done to attached entities automatically. You shouldn't ever call update, merge or saveOrUpdate on an attached entity. Just do
Email email = session.get(emailId);
email.setSubject(subject);
No need to call update. Hibernate will flush the changes automatically before committing the transaction.
回答5:
I had the this problem on my project.
After I implemented optimistic locking, I got the same exception.
My mistake was that I did not remove the setter of the field that became the @Version. As the setter was being called in java space, the value of the field did not match the one generated by the DB anymore. So basically the version fields did not match anymore. At that point any modification on the entity resulted in:
org.hibernate.StaleObjectStateException: Row was updated or deleted by another transaction (or unsaved-value mapping was incorrect)
I am using H2 in memory DB and Hibernate.
回答6:
check if the object exists or not in DB, if it exists get the object and refresh it:
if (getEntityManager().contains(instance)) {
getEntityManager().refresh(instance);
return instance;
}
if it fails the above if condition... find the Object with Id in DB, do the operation which you need, in this case exactly changes will reflects.
if (....) {
} else if (null != identity) {
E dbInstance = (E) getEntityManager().find(instance.getClass(), identity);
return dbInstance;
}
回答7:
This error occurred for me when I was trying to update the same row from 2 different sessions. I updated a field in one browser while a second was open and had already stored the original object in its session. When I attempted to update from this second "stale" session I get the stale object error. In order to correct this I refetch my object to be updated from the database before I set the value to be updated, then save it as normal.
回答8:
I had the experienced the same issue in different context of my project and there are different scenarios like
- object is accessed from various source like (server side and client)
- without any interval accessing the same object from a different place
In the first case
When I issue a server cal, before save the that object their one call from js and trying to save and another place, I got like, js call is going two, three times(I thing that call binding thing cause the issue)
I solved by
e.preventDefault()
The second case,
object.lock()
回答9:
I had the same problem and in my case the problem was missing and/or incorrect equals implementation on some types of fields in the entity object. At commit time, Hibernate checks ALL entities loaded in the session to check if they are dirty. If any of the entities are dirty, hibernate tries to persist them - no matter of the fact that the actual object that is requested a save operation is not related to the other entities.
Entity dirtiness is done by comparing every property of given object (with their equals methods) or UserType.equals if property has an associated org.Hibernate.UserType.
Another thing that surprised me was, in my transaction (using Spring annotation @Transactional), I was dealing with a single entity. Hibernate was complaining about some random entity that's unrelated to that entity being saved. What I realized is there is an outermost transaction we create at REST controller level, so the scope of the session is too big and hence all objects ever loaded as part of request processing get checked for dirtiness.
Hope this helps someone, some day.
Thanks Rags
回答10:
Just in case someone checked this thread and had the same issue as mine...
Row was updated or deleted by another transaction (or unsaved-value mapping was incorrect)
I'm using NHibernate, I receive same error, during creating an object...
I was passing the key manually, and also specified a GUID generator in mapping, so hibernate generate same exact error for me, so once I removed the GUID, and left the field empty, everything went just fine.
this answer may not help you, but will help someone like me, who just your thread becasue of same error
回答11:
I also ran into this error when attempting to update an existing row after creating a new one, and spent ages scratching my head, digging through transaction and version logic, until I realised that I had used the wrong type for one of my primary key columns.
I used LocalDate when I should have been using LocalDateTime – I think this was causing hibernate to not be able to distinguish entities, leading to this error.
After changing the key to be a LocalDateTime, the error went away. Also, updating individual rows began to work as well – previously it would fail to find a row for updating, and testing this separate issue was actually what led me to my conclusions regarding the primary key mapping.
回答12:
Don't set an Id to the object you are saving as the Id will be autogenerated
回答13:
I had the same problem in my grails project. The Bug was, that i overwrite the getter method of a collection field. This returned always a new version of the collection in other thread.
class Entity {
List collection
List getCollection() {
return collection.unique()
}
}
The solution was to rename the getter method:
class Entity {
List collection
List getUniqueCollection() {
return collection.unique()
}
}
回答14:
I've also receiving such an exception, but the problem was in my Entity identifier. I am using UUID and there are some problems in the way Spring works with them. So I just added this line to my entity identifier and it began working:
@Column(columnDefinition = "BINARY(16)")
Here you can find a little bit more information.
回答15:
In order to prevent StaleObjectStateException, in your hbm file write below code:
<timestamp name="lstUpdTstamp" column="LST_UPD_TSTAMP" source="db"/>
回答16:
I have also faced this issue. First check your imports, when you use session,transaction it should be org.hibernate and remove @Transactinal annotation. and most important in Entity class if you have used @GeneratedValue(strategy=GenerationType.AUTO) or anyother then at the time of model object creation/entity object creation should not create id. final conclusion is if you want pass id filed i.e PK then remove @GeneratedValue from entity class.
回答17:
I had this problem in one of my apps, now, I know this is an old thread but here is my solution; I figured out by looking at the data inside the debugger that JVM actually didn't load it properly when Hibernate was trying to update the database (that is actually done in a different thread), so I added the keyword "volatile" to every field of the entities. It has some performance issues to do that but rather that than Heavy objects beeing thrown around...
来源：https://stackoverflow.com/questions/8645694/row-was-updated-or-deleted-by-another-transaction-or-unsaved-value-mapping-was