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From "Gary Gregory (JIRA)" <j...@apache.org>
Subject [jira] [Commented] (DBCP-398) DBCP hangs on common pool borrowObject when PoolableConnection is used and the underlying connection closed unexpectedly (connection resets/timouts)
Date Wed, 22 May 2013 17:31:25 GMT

    [ https://issues.apache.org/jira/browse/DBCP-398?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=13664292#comment-13664292
] 

Gary Gregory commented on DBCP-398:
-----------------------------------

A seemingly simple change like replacing {{isClosed()}} the implementation with: 

{code:java}
    public boolean isClosed() throws SQLException {
        return _conn == null ? true : _conn.isClosed();
    }
{code}

causes a lot of unit tests to fail.

You can get the code from https://svn.apache.org/repos/asf/commons/proper/dbcp/branches/DBCP_1_4_x_BRANCH
and try it yourself.

You can then provide a patch. You use an local Java database like H2 or HyperSQL for your
unit tests.

The next release would be 1.4.1, which we could push out ASAP since there are other fixes
ready.


                
> DBCP hangs on common pool borrowObject when PoolableConnection is used and the underlying
connection closed unexpectedly (connection resets/timouts)
> ----------------------------------------------------------------------------------------------------------------------------------------------------
>
>                 Key: DBCP-398
>                 URL: https://issues.apache.org/jira/browse/DBCP-398
>             Project: Commons Dbcp
>          Issue Type: Bug
>            Reporter: Sarvesh Sakalanaga
>
> The bug is in org.apache.commons.dbcp.PoolableConnection as isClosed method on this calls
super.isClosed which returns true (as DelegatingConnection::isClosed { _closed || _conn.isClosed()
}). Since PoolableConnection needs to release objects to pool even if the underlying connection
is closed the isClosed method should be overridden in this class and should return _closed.
This _closed is the delegating connection close which will be set to false even if the underlying
connection is closed (_conn.isClosed). The fix should also not throw on PoolableConnection::Close
method if underlying connection is closed as this state is a valid state and is expected.
> Also currently the way it stands the clients of PoolableConnection will/may not call
Close() as isClosed always returns true in this case.
> Below is the stack that the thread hangs on:
> ◾waiting on <0x00000007b5a50e48> (a org.apache.commons.pool.impl.GenericObjectPool$Latch)
>  at java.lang.Object.wait(Object.java:503)
>  at org.apache.commons.pool.impl.GenericObjectPool.borrowObject(GenericObjectPool.java:1104)
> ◾locked <0x00000007b5a50e48> (a org.apache.commons.pool.impl.GenericObjectPool$Latch)
>  at org.apache.commons.dbcp.PoolingDataSource.getConnection(PoolingDataSource.java:106)
>  at org.datanucleus.store.rdbms.ConnectionProviderPriorityList.getConnection(ConnectionProviderPriorityList.java:57)
>  at org.datanucleus.store.rdbms.ConnectionFactoryImpl$ManagedConnectionImpl.getConnection(ConnectionFactoryImpl.java:354)
>  at org.datanucleus.store.rdbms.ConnectionFactoryImpl$ManagedConnectionImpl.getXAResource(ConnectionFactoryImpl.java:314)
>  at org.datanucleus.store.connection.ConnectionManagerImpl.enlistResource(ConnectionManagerImpl.java:386)
>  at org.datanucleus.store.connection.ConnectionManagerImpl.allocateConnection(ConnectionManagerImpl.java:252)
>  at org.datanucleus.store.connection.AbstractConnectionFactory.getConnection(AbstractConnectionFactory.java:60)
>  at org.datanucleus.store.AbstractStoreManager.getConnection(AbstractStoreManager.java:449)
>  at org.datanucleus.store.AbstractStoreManager.getConnection(AbstractStoreManager.java:418)
>  at org.datanucleus.store.rdbms.query.JDOQLQuery.performExecute(JDOQLQuery.java:595)

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