[DBCP-398] DBCP hangs on common pool borrowObject when PoolableConnection is used and the underlying connection closed unexpectedly (connection resets/timouts)

• Type: Bug
• Status: Closed
• Priority: Major
• Resolution: Fixed
• Affects Version/s: 1.2, 1.3, 1.4, 2.0
• Assignee: Unassigned
• Reporter: Sarvesh Sakalanaga
• Created: 21/May/13 19:59
• Updated: 11/Apr/15 04:25
• Resolved: 03/Feb/14 21:27

Description

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)