[hibernate-issues] [Hibernate-JIRA] Commented: (HHH-2131) SYBASE +select for update is showing deadlock because lock is not working properly

[Michel HAMON (JIRA)]

    [ http://opensource.atlassian.com/projects/hibernate/browse/HHH-2131?page=comments#action_26301 ] 

Michel HAMON commented on HHH-2131:
-----------------------------------

Hi,

I think that:
MyClass myClass = (MyClass) session.get(MyClass.class,id)); 
session.lock(myClass,LockMode.UPGRADE); 
doesn't work because 2 differents thread can execute "session.get", both retrieve the same value. 

I can't use hibernate.connection.isolation=4 because in this mode all select hold a lock.

session.get("MyClass", id, LockMode.UPGRADE) should always lock the row, with both Sybase AND Oracle.

With Sybase: session.get(MyClass.class, id, LockMode.UPGRADE) should generate something like 
update TableName set keyColumn=key where keyColumn=key
select * from  TableName where keyColumn=key
instead of
select * from TableName holdlock where keyColumn=key

I think that Hibernate should run the same way with all database.

> SYBASE +select for update is showing deadlock because lock is not working properly
> ----------------------------------------------------------------------------------
>
>          Key: HHH-2131
>          URL: http://opensource.atlassian.com/projects/hibernate/browse/HHH-2131
>      Project: Hibernate3
>         Type: Bug

>   Components: core
>     Versions: 3.1.3
>  Environment: sybaseASE 12.5.03  in solaris +hibernate3.1.3 
>     Reporter: George Thomas

>
>
> I am connecting to Sybase database from hibernate.I tried setting locks using while selecting rows
> 1.session.load(class,id,LOCKMODE.UPGRADE)
> 2.session.lock(obj,LOCKMODE.UPGRADE) 
> I am attaching a sample code while updating a field in table fund after selecting it.
> {
>   Fund fund = null;
>   ClientCredential credential = new ClientCredential("testDatabase", fund);
>   org.hibernate.Session session = SessionFactoryManager.getSessionFactory(credential).getCurrentSession();
>   Transaction transaction = session.beginTransaction();
>   log.info("Run by " + Thread.currentThread().getName());
>   fund = (Fund) session.get(Fund.class, new Short((short)12), LockMode.UPGRADE);
>   fund.setLegalEntityOrgId(fund.getLegalEntityOrgId()+1);
>   transaction.commit();
> }
> my requirement was that i wanted to do a select for update.I should acquire lock on certain rows and do a matching and if concurrent request comes ,it should wait till transaction is over that is lock is released.
> When I went through the hibernate code,the hibernate is making static queries in the beginning while loading session factory.Since we are appending the holdlock during execution,the sybase dialect is not appending.
> As a work around I tested with native sql with holdlock but when I test concurrent request using threads its bombing.Its throwing LockAcquisitionException.( Your server command (family id #0, process id #3777) encountered a deadlock situation.).can anyone give a solution to this problem???
> org.hibernate.exception.LockAcquisitionException: could not update: [com.citco.aexeo.common.dataaccess.domain.Fund#12]
> at org.hibernate.exception.SQLStateConverter.convert(SQLStateConverter.java:84)
> at org.hibernate.exception.JDBCExceptionHelper.convert(JDBCExceptionHelper.java:43)
> at org.hibernate.persister.entity.AbstractEntityPersister.update(AbstractEntityPersister.java:2223)
> at org.hibernate.persister.entity.AbstractEntityPersister.updateOrInsert(AbstractEntityPersister.java:2118)
> at org.hibernate.persister.entity.AbstractEntityPersister.update(AbstractEntityPersister.java:2375)
> at org.hibernate.action.EntityUpdateAction.execute(EntityUpdateAction.java:91)
> at org.hibernate.engine.ActionQueue.execute(ActionQueue.java:250)
> at org.hibernate.engine.ActionQueue.executeActions(ActionQueue.java:233)
> at org.hibernate.engine.ActionQueue.executeActions(ActionQueue.java:140)
> at org.hibernate.event.def.AbstractFlushingEventListener.performExecutions(AbstractFlushingEventListener.java:297)
> at org.hibernate.event.def.DefaultFlushEventListener.onFlush(DefaultFlushEventListener.java:27)
> at org.hibernate.impl.SessionImpl.flush(SessionImpl.java:985)
> at org.hibernate.impl.SessionImpl.managedFlush(SessionImpl.java:333)
> at org.hibernate.transaction.JDBCTransaction.commit(JDBCTransaction.java:107)
> at com.satyam.Testing.doTransaction(Testing.java:103)
> at com.satyam.MyRunnable.run(MyRunnable.java:13)
> at java.lang.Thread.run(Thread.java:568)
> Caused by: com.sybase.jdbc2.jdbc.SybSQLException: Your server command (family id #0, process id #3777) encountered a deadlock situation. Please re-run your command.
> at com.sybase.jdbc2.tds.Tds.processEed(Tds.java:2636)
> at com.sybase.jdbc2.tds.Tds.nextResult(Tds.java:1996)
> at com.sybase.jdbc2.jdbc.ResultGetter.nextResult(ResultGetter.java:69)
> at com.sybase.jdbc2.jdbc.SybStatement.nextResult(SybStatement.java:204)
> at com.sybase.jdbc2.jdbc.SybStatement.nextResult(SybStatement.java:187)
> at com.sybase.jdbc2.jdbc.SybStatement.updateLoop(SybStatement.java:1642)
> at com.sybase.jdbc2.jdbc.SybStatement.executeUpdate(SybStatement.java:1625)
> at com.sybase.jdbc2.jdbc.SybPreparedStatement.executeUpdate(SybPreparedStatement.java:91)
> at org.hibernate.jdbc.NonBatchingBatcher.addToBatch(NonBatchingBatcher.java:23)
> at org.hibernate.persister.entity.AbstractEntityPersister.update(AbstractEntityPersister.java:2205)
> ... 14 more

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