[jira] [Updated] (OPENJPA-2904) OpenJPAEntityManager.getConnection() may lead to sudden connection closure

["Pawel Veselov (Jira)" <ji...@apache.org>]

     [ https://issues.apache.org/jira/browse/OPENJPA-2904?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel ]

Pawel Veselov updated OPENJPA-2904:
-----------------------------------
    Priority: Minor  (was: Major)

> OpenJPAEntityManager.getConnection() may lead to sudden connection closure
> --------------------------------------------------------------------------
>
>                 Key: OPENJPA-2904
>                 URL: https://issues.apache.org/jira/browse/OPENJPA-2904
>             Project: OpenJPA
>          Issue Type: Bug
>    Affects Versions: 3.2.0, 3.2.1, 3.2.2
>            Reporter: Pawel Veselov
>            Priority: Minor
>
> (looking at commit 05069dfee, but this code hasn't changed in ages).
> There is a number of methods that chain to {{JDBCStore.getClientConnection()}}
> * {{StoreManager.getClientConnection()}}
> * {{StoreContext.getConnection()}}
> * {{OpenJPAEntityManager.getConnection()}}
> * {{EntityManagerImpl.unwrap()}}
> Callers of these methods typically use the retrieved connection object for an operation, and then let go of it, without any cleanup (as they are supposed to).
> However, {{JDBCStore.getClientConnection()}} implementation creates an instance of {{JDBCStoreManager.ClientConnection}} class every time it's called. These instances, considering how they are used, are therefore short-lived
> However, the implementation {{JDBCStoreManager.ClientConnection}} closes the underlying connection object on finalization.
> This has a relatively high chance of having the underlying connection closed before it's actually properly released.
> I don't necessarily know what the right fix for this is, but locally I will just make ClientConnection a field of RefCountConnection, it's a lightweight class so I can create it right away, then I'll have {{JDBCStore.getClientConnection()}} just return that. There may be some gotchas there, but I just need a quick solution because this suddenly became a persistent problem.
> I've overridden the pooled connection implementation to try to trace the connection random connection closure that we are experiencing under some random scenarios, and I attached an exception to the connection object when it's closed, and I see when an attempt to use a closed connection happens - it's because the GC closed it through {{JDBCStoreManager.ClientConnection}}.



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