[infinispan-issues] [JBoss JIRA] (ISPN-2013) Using explicit "unlock" causes TimeoutException for other Threads

[Pedro Ruivo (JIRA)]

    [ https://issues.jboss.org/browse/ISPN-2013?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=12798280#comment-12798280 ] 

Pedro Ruivo commented on ISPN-2013:
-----------------------------------

Hi [~dudalov]. can you tell me your use case? 

Although I think that it is bad to allow the programmer to unlock locks in the middle of the transaction, I've made some changes to allow it. However, your tests is reporting inconsistencies (java.util.ConcurrentModificationException: Cache inconsistent: value=value, nextValue=value-1) that make sense to happen because you're releasing a lock before the transaction commit. So the next TX will see old values from some keys and new values for other keys. That's why I'm asking for your use case.

                
> Using explicit "unlock" causes TimeoutException for other Threads
> -----------------------------------------------------------------
>
>                 Key: ISPN-2013
>                 URL: https://issues.jboss.org/browse/ISPN-2013
>             Project: Infinispan
>          Issue Type: Bug
>          Components: Locking and Concurrency
>    Affects Versions: 5.1.2.FINAL
>         Environment: Windows 7 64-bit
>            Reporter: Dmitry Udalov
>            Assignee: Pedro Ruivo
>             Fix For: 6.0.0.Final
>
>         Attachments: LockTest.java
>
>
> In a test I have several tasks that run on a single cache node configured as transactional pessimistic replicated cache. If I explicitly call "unlock" then I consistently see TimeoutException reported by some tasks. Without explicit "unlock" the test works fine. Does it mean that I should never call "unlock" and rely on transaction.commit/rollback ? It's seen with infinispan-5.1.2.FINAL
>  
> Here's what in a nutshell each task does:
>  
> final lockKey = ...
>  
> executor.submit(new Callable<Boolean>()   {
>    public Boolean call() throws Exception
>  
>       TransactionManager tx = cache.getAdvancedCache().getTransactionManager(); 
>       tx.begin()
>       try {
>           if ( lockManager.lock(lockKey) ) {
>  
>              // ...
>          
>              // removing next line makes test happy. Otherwise some tasks report TimeoutException (pls. see the stack traces)
>              cache.getLockManager().unlock(lockKey);      
>           }
>       }   catch(Throwable t) {
>           tx.setRollbackOnly();
>       }  finally {
>           if (ut.getStatus() == Status.STATUS_ACTIVE)
>               ut.commit();
>           else
>              ut.rollback();
>       }
>  
>  
> By the time I received that exception all other tasks were completed and they released the lock on the key in question.
> I also see that LockManagerImpl.lock recognized that the lock was not owned by any thread - see "Lock held by [null]", which seems to be right. But yet the lock failed to be acquired.
> Is it a matter to trying it one more time?
>  
> org.infinispan.util.concurrent.TimeoutException: Unable to acquire lock after [10 seconds] on key [foo] for requestor [GlobalTransaction:<Sound-15075>:8:local]! Lock held by [null]
>     at org.infinispan.util.concurrent.locks.LockManagerImpl.lock(LockManagerImpl.java:206)
>     at org.infinispan.util.concurrent.locks.LockManagerImpl.acquireLock(LockManagerImpl.java:180)
>     at org.infinispan.util.concurrent.locks.LockManagerImpl.acquireLock(LockManagerImpl.java:170)
>     at org.infinispan.interceptors.locking.AbstractTxLockingInterceptor.lockKeyAndCheckOwnership(AbstractTxLockingInterceptor.java:209)
>     at org.infinispan.interceptors.locking.AbstractTxLockingInterceptor.lockAndRegisterBackupLock(AbstractTxLockingInterceptor.java:136)
>     at org.infinispan.interceptors.locking.PessimisticLockingInterceptor.visitLockControlCommand(PessimisticLockingInterceptor.java:228)
>     at org.infinispan.commands.control.LockControlCommand.acceptVisitor(LockControlCommand.java:129)
>     at org.infinispan.interceptors.base.CommandInterceptor.invokeNextInterceptor(CommandInterceptor.java:116)
>     at org.infinispan.interceptors.base.CommandInterceptor.handleDefault(CommandInterceptor.java:130)
>     at org.infinispan.commands.AbstractVisitor.visitLockControlCommand(AbstractVisitor.java:159)
>     at org.infinispan.commands.control.LockControlCommand.acceptVisitor(LockControlCommand.java:129)
>     at org.infinispan.interceptors.base.CommandInterceptor.invokeNextInterceptor(CommandInterceptor.java:116)
>     at org.infinispan.interceptors.TxInterceptor.visitLockControlCommand(TxInterceptor.java:144)
>     at org.infinispan.commands.control.LockControlCommand.acceptVisitor(LockControlCommand.java:129)
>     at org.infinispan.interceptors.base.CommandInterceptor.invokeNextInterceptor(CommandInterceptor.java:116)
>     at org.infinispan.interceptors.StateTransferLockInterceptor.handleWithRetries(StateTransferLockInterceptor.java:207)
>     at org.infinispan.interceptors.StateTransferLockInterceptor.visitLockControlCommand(StateTransferLockInterceptor.java:138)
>     at org.infinispan.commands.control.LockControlCommand.acceptVisitor(LockControlCommand.java:129)
>     at org.infinispan.interceptors.base.CommandInterceptor.invokeNextInterceptor(CommandInterceptor.java:116)
>     at org.infinispan.interceptors.base.CommandInterceptor.handleDefault(CommandInterceptor.java:130)
>     at org.infinispan.commands.AbstractVisitor.visitLockControlCommand(AbstractVisitor.java:159)
>     at org.infinispan.commands.control.LockControlCommand.acceptVisitor(LockControlCommand.java:129)
>     at org.infinispan.interceptors.base.CommandInterceptor.invokeNextInterceptor(CommandInterceptor.java:116)
>     at org.infinispan.interceptors.InvocationContextInterceptor.handleAll(InvocationContextInterceptor.java:130)
>     at org.infinispan.interceptors.InvocationContextInterceptor.visitLockControlCommand(InvocationContextInterceptor.java:94)
>     at org.infinispan.commands.control.LockControlCommand.acceptVisitor(LockControlCommand.java:129)
>     at org.infinispan.interceptors.InterceptorChain.invoke(InterceptorChain.java:345)
>     at org.infinispan.CacheImpl.lock(CacheImpl.java:484)
>     at org.infinispan.CacheImpl.lock(CacheImpl.java:468)

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