[hibernate-issues] [Hibernate-JIRA] Commented: (HHH-1786) JTASessionContext.CleanupSynch does not remove sessions from currentSessionMap

[Gary Sargent (JIRA)]

    [ http://opensource.atlassian.com/projects/hibernate/browse/HHH-1786?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=31084#action_31084 ] 

Gary Sargent commented on HHH-1786:
-----------------------------------

Having looked into this further, in JTASessionContext, the map is being populated with a different key to that used when it is being read (in the two places a get and a remove are performed on the Map). 

This will work fine for non-Websphere transaction lookups as the default implementation returns the transaction, which is what is used for the get / remove. 

For WebSphere, this won't work as this uses a different key. This means a new session is ALWAYS created even if one exists, and sessions are NEVER removed! 

Solution is to ensure the correct key is used in the get and remove methods on the Map. Diff for JTASessionContext.java against 3.3.0 is: 

104c104,107 
< Session currentSession = ( Session ) currentSessionMap.get( txn ); 
--- 
> Object txnIdentifier = factory.getSettings().getTransactionManagerLookup() == null 
> ? txn 
> : factory.getSettings().getTransactionManagerLookup().getTransactionIdentifier( txn ); 
> Session currentSession = ( Session ) currentSessionMap.get( txnIdentifier ); 
110c113 
< txn.registerSynchronization( buildCleanupSynch( txn ) ); 
--- 
> txn.registerSynchronization( buildCleanupSynch( txnIdentifier ) ); 
122,124d124 
< Object txnIdentifier = factory.getSettings().getTransactionManagerLookup() == null 
< ? txn 
< : factory.getSettings().getTransactionManagerLookup().getTransactionIdentifier( txn ); 
131,132c131,132 
< private CleanupSynch buildCleanupSynch(Transaction txn) { 
< return new CleanupSynch( txn, this ); 
--- 
> private CleanupSynch buildCleanupSynch(Object txnIdentifier) { 
> return new CleanupSynch( txnIdentifier, this ); 
183c183 
< private Transaction txn; 
--- 
> private Object txnIdentifier; 
186,187c186,187 
< public CleanupSynch(Transaction txn, JTASessionContext context) { 
< this.txn = txn; 
--- 
> public CleanupSynch(Object txnIdentifier, JTASessionContext context) { 
> this.txnIdentifier = txnIdentifier; 
201c201 
< context.currentSessionMap.remove( txn ); 
--- 
> Object x = context.currentSessionMap.remove( txnIdentifier ); 

> JTASessionContext.CleanupSynch does not remove sessions from currentSessionMap
> ------------------------------------------------------------------------------
>
>                 Key: HHH-1786
>                 URL: http://opensource.atlassian.com/projects/hibernate/browse/HHH-1786
>             Project: Hibernate3
>          Issue Type: Improvement
>    Affects Versions: 3.1.2
>         Environment: IBM WebSphere 6.0.2.7, Hibernate CVS snapshot from 2006-02-24
>            Reporter: Tomi Szabo
>            Assignee: Steve Ebersole
>             Fix For: 3.3.0.CR2
>
>         Attachments: JTASessionContext.java, screenshot-1.jpg, screenshot-2.jpg, WebSphereExtendedJTATransactionLookup.java, WebSphereExtendedJTATransactionLookup.patch.txt
>
>
> We are using JTASessionContext, CMTTransaction and WebSphereExtendedJTATransactionLookup. We have experienced some memmory leak problems and after closer inspection we have found that Hibernate sessions are not removed from currentSessionMap inside JTASessionContext.
> Method JTASessionContext.CleanupSynch.afterCompletion() is called as expected but code "context.currentSessionMap.remove( txn );" does not remove session from Map because of key's hashcode has changed. This is due to fact that com.ibm.websphere.jtaextensions.ExtendedJTATransaction.hashCode is actually ID of underlaying transaction. But if it comes to the afterCompletion method in CleanupSynch the underlaying transaction is already closed. Closed transaction has ID 0 (default value) and it is different from ID under which the Hibernate session was previously inserted into Map.
> Possible patch is in attachements.

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