[POOL-131] Make org.apache.commons.pool.impl.GenericObjectPool.returnObject(Object) log errors about passivation/destroying

• Type: Improvement
• Status: Closed
• Priority: Major
• Resolution: Fixed
• Affects Version/s: 1.4
• Fix Version/s: 2.0

Environment

Spring Framework JTA transaction Manager + jBossTS + DBCP

• Assignee: Unassigned
• Reporter: Mauro Molinari
• Created: 18/Dec/08 11:05
• Updated: 31/Dec/14 16:33
• Resolved: 11/Apr/12 20:58

Description

In our environment it happens the following. Suppose our code has a bug and does not release a connection previously obtained from DBCP.
Suppose a JTA transaction is in progress when this happens.
When trying to commit this transaction, Spring has a guard that realizes that the owner of that transaction is in some way "dead", so it tries to close the connection before committing (I think this is a problem, however, let's go on). Closing the connection makes DBCP/Pool call returnObject on the GenericObjectPool, then addObjectToPool and, at last, passivateObject. As the connection is neither in auto-commit mode nor read-only, passivateObject issues a rollback on the connection but then jBossTS throws a SQLException saying that it is not allowed to issue a rollback on an underlying connection while a higher level JTA transaction is in progress. This exception is caught by returnObject and it is completely lost, because returnObject does not log it, nor it forwards it upward.

The final result is that:

• the connection is not given back to the Pool, because of the exception
• however, the physical underlying connection to the DBMS remains open
  => we have a connection leak, without any proof of it (no exceptions are logged in any way)

To get to these results I had to carefully debug my code. It would have been very easier if Pool logged exceptions thrown during passivation.