[ http://issues.apache.org/jira/browse/DBCP-202?page=all ]
Phil Steitz updated DBCP-202:
-----------------------------
Fix Version/s: 1.3
Affects Version/s: 1.2.2
(was: 1.3)
> Deadlock creating/closing PreparedStatement
> -------------------------------------------
>
> Key: DBCP-202
> URL: http://issues.apache.org/jira/browse/DBCP-202
> Project: Commons Dbcp
> Issue Type: Bug
> Affects Versions: 1.2.2
> Reporter: Gustavo Huff Mauch
> Fix For: 1.3
>
>
> Hi!
> I´m using DBCP in a multi-threaded app. Sometimes a few threads share the
> same connection (obtained from the same BasicDatasource) and quite often the
> application just hangs. Looking a bit further i found out that it hangs when
> one thread is creating a PreparedStatement and the other one is closing
> another PreparedStatement.
> I connected to my app with jConsole and i was able to see the stacktrace for
> two threads that blocked one another. Here is:
>
> Name: pool-1-thread-1
> State: BLOCKED on [EMAIL PROTECTED] owned by: pool-1-thread-2
> Total blocked: 137 Total waited: 1
> Stack trace:
> org.apache.commons.pool.impl.GenericKeyedObjectPool.borrowObject(GenericKeyedObjectPool.java:767)
> org.apache.commons.dbcp.PoolingConnection.prepareStatement(PoolingConnection.java:87)
> org.apache.commons.dbcp.DelegatingConnection.prepareStatement(DelegatingConnection.java:185)
> org.apache.commons.dbcp.PoolingDataSource$PoolGuardConnectionWrapper.prepareStatement(PoolingDataSource.java:278)
> dmview.common.Database.prepareStatement(Database.java:829)
> dmview.monitor.polling.ProxyUpdater.insertAllSlotPortsIntoDb(ProxyUpdater.java:801)
> dmview.monitor.polling.ProxyUpdater.insertSlotIntoDb(ProxyUpdater.java:718)
> dmview.monitor.polling.ProxyUpdater.updateDevice(ProxyUpdater.java:296)
> dmview.monitor.polling.ProxyUpdater.update(ProxyUpdater.java:81)
> dmview.monitor.polling.Poller.run(Poller.java:183)
> java.util.concurrent.ThreadPoolExecutor$Worker.runTask(Unknown Source)
> java.util.concurrent.ThreadPoolExecutor$Worker.run(Unknown Source)
> java.lang.Thread.run(Unknown Source)
> The stacktrace for the second thread :
> Name: pool-1-thread-2
> State: BLOCKED on [EMAIL PROTECTED] owned by: pool-1-thread-1
> Total blocked: 107 Total waited: 1
> Stack trace:
> org.apache.commons.dbcp.AbandonedTrace.removeTrace(AbandonedTrace.java:221)
> org.apache.commons.dbcp.PoolablePreparedStatement.passivate(PoolablePreparedStatement.java:100)
> org.apache.commons.dbcp.PoolingConnection.passivateObject(PoolingConnection.java:239)
> org.apache.commons.pool.impl.GenericKeyedObjectPool.returnObject(GenericKeyedObjectPool.java:970)
> org.apache.commons.dbcp.PoolablePreparedStatement.close(PoolablePreparedStatement.java:78)
> org.apache.commons.dbcp.DelegatingStatement.close(DelegatingStatement.java:165)
> dmview.monitor.polling.ProxyUpdater.insertAllSlotPortsIntoDb(ProxyUpdater.java:883)
> dmview.monitor.polling.ProxyUpdater.insertSlotIntoDb(ProxyUpdater.java:718)
> dmview.monitor.polling.ProxyUpdater.updateDevice(ProxyUpdater.java:296)
> dmview.monitor.polling.ProxyUpdater.update(ProxyUpdater.java:81)
> dmview.monitor.polling.Poller.run(Poller.java:183)
> java.util.concurrent.ThreadPoolExecutor$Worker.runTask(Unknown Source)
> java.util.concurrent.ThreadPoolExecutor$Worker.run(Unknown Source)
> java.lang.Thread.run(Unknown Source)
> The line 829 from method Database.prepareStatement (last one from my app
> before DBCP, in first stacktrace) is :
> PreparedStatement ret = conexao.prepareStatement(sql);
> where "conexao" is a java.sql.Connection obtained from the pool.
> The line 883 in method ProxyUpdater.insertAllSlotPortsIntoDb (last one from
> my app before DBCP, in second stacktrace) is :
> insertPortTest.close();
> where insertPortTest is a PreparedStatement.
> It all seems to me that creating/closing PreparedStatements using the same
> connection from a BasicDatasource instance can cause a racing condition where
> two (or more) threads may block one another. Am i correct? Is this really a
> bug?
> Thanks in advance!
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