> It must be useful to add connection limit feature to TestDriver.
>
> ++connectionCount in Driver.connect() and --connectionCount in
> Connection.close().
>
assertTrue( Driver.connectionCount <= getMaxActive() ) at the end of tests.
getMaxActive() == 1 is "good" number.
>
> ----- Original Message -----
> From: "Todd Carmichael" <[EMAIL PROTECTED]>
> To: "'Jakarta Commons Developers List'" <[EMAIL PROTECTED]>
> Sent: Monday, October 27, 2003 8:45 PM
> Subject: RE: [dbcp] Trying to track/find a connection leak in DBCP 1.1
>
>
> > I did perform this test. Perhaps the original email was not clear in
> > referencing the test of using JndiDataSourceFactory and that no leaks
> > occurred.
> >
> > ToddC
> >
> >
> > -----Original Message-----
> > From: Juozas Baliuka [mailto:[EMAIL PROTECTED]
> > Sent: Monday, October 27, 2003 9:53 AM
> > To: Jakarta Commons Developers List
> > Subject: Re: [dbcp] Trying to track/find a connection leak in DBCP 1.1
> >
> >
> >
> > Try to run app without pool first to find broken component. Most of
> > Connection leak problems are in applications and it is not easy to trust
> > this test.
> >
> > ----- Original Message -----
> > From: "Todd Carmichael" <[EMAIL PROTECTED]>
> > To: <[EMAIL PROTECTED]>
> > Sent: Monday, October 27, 2003 7:32 PM
> > Subject: [dbcp] Trying to track/find a connection leak in DBCP 1.1
> >
> >
> > > Our scalability tests against our web application (350 concurrent
> > > users in
> > a
> > > web application using Tomcat 4.1.24 with JDK 1.4.2) is failing due to
> > > a continual leak of database connections. The test failed in that the
> > number
> > > of database connections (reported by the DB server: MS SQL Server)
> > > grew to over a thousand during an hour plus test (using the microsoft
> > > sql jdbc driver though we have tried the i-net driver with similar
> > > results). We
> > know
> > > that it is not a problem in the application because we have performed
> > > identical tests except to configure Torque to use the
> > JndiDatasourceFactory.
> > > This in passes the connection pooling chores to the appserver. Both
> > SunOne
> > > appserver and Weblogic appserver maintained a valid number of
> > > connections
> > (<
> > > 75). We are using Torque 3.1 with DBCP 1.1 (using the
> > > org.apache.commons.dbcp.datasources.SharedPoolDataSource) and Pool
> > > 1.1.
> > >
> > > Our settings in our torque.properties (which can passed down to the
> > > SHaredPoolDataSource) are:
> > >
> > > torque.dsfactory.default.pool.maxActive=100
> > > torque.dsfactory.default.pool.testOnBorrow=0
> > > torque.dsfactory.default.pool.testOnReturn=0
> > > #no setting for maxIdle. It defaults to 8. Not optimal but code
> > > should still work:
> > > torque.dsfactory.default.pool.timeBetweenEvictionRunsMillis=60000
> > > torque.dsfactory.default.pool.numTestsPerEvictionRun=-1
> > > torque.dsfactory.default.pool.minEvictableIdleTimeMillis=1000
> > > torque.dsfactory.default.pool.testWhileIdle=false
> > >
> > > I have begun some debugging of this problem. I have added some debug
> > output
> > > in the torqueInstance.getConnection to track size of the pool.
> > >
> > > iCountConnections++;
> > > if ((iCountConnections % 100)==0)
> > > {
> > > SharedPoolDataSource spds =
> > > (SharedPoolDataSource)dsf.getDataSource();
> > > log.warn("Current Num Active Connections=" +
> > > String.valueOf(spds.getNumActive()));
> > > log.warn("Current Num Idle Connections=" +
> > > String.valueOf(spds.getNumIdle()));
> > > log.warn("Max Active =" +
> > > String.valueOf(spds.getMaxActive()));
> > > log.warn("Max Idle =" +
> > String.valueOf(spds.getMaxIdle()));
> > > log.warn("Max Wait =" +
> > String.valueOf(spds.getMaxWait()));
> > > }
> > >
> > > Here is a sample of the output when I run our scalability tests. At
> > > this point the system is under heavy load and the db server is
> > > reporting over
> > 100
> > > connections:
> > >
> > > [WARN] TorqueInstance - -Current Num Active Connections=3 [WARN]
> > > TorqueInstance - -Current Num Idle Connections=5 [WARN] TorqueInstance
> > > - -Max Active =100 [WARN] TorqueInstance - -Max Idle =8
> > > [WARN] TorqueInstance - -Max Wait =500
> > > [WARN] TorqueInstance - -Current Num Active Connections=5
> > > [WARN] TorqueInstance - -Current Num Idle Connections=3
> > > [WARN] TorqueInstance - -Max Active =100
> > > [WARN] TorqueInstance - -Max Idle =8
> > > [WARN] TorqueInstance - -Max Wait =500
> > > [WARN] TorqueInstance - -Current Num Active Connections=19
> > > [WARN] TorqueInstance - -Current Num Idle Connections=0
> > > [WARN] TorqueInstance - -Max Active =100
> > > [WARN] TorqueInstance - -Max Idle =8
> > > [WARN] TorqueInstance - -Max Wait =500
> > > [WARN] TorqueInstance - -Current Num Active Connections=32
> > > [WARN] TorqueInstance - -Current Num Idle Connections=0
> > > [WARN] TorqueInstance - -Max Active =100
> > > [WARN] TorqueInstance - -Max Idle =8
> > > [WARN] TorqueInstance - -Max Wait =500
> > > [WARN] TorqueInstance - -Current Num Active Connections=39
> > > [WARN] TorqueInstance - -Current Num Idle Connections=1
> > > [WARN] TorqueInstance - -Max Active =100
> > > [WARN] TorqueInstance - -Max Idle =8
> > > [WARN] TorqueInstance - -Max Wait =500
> > > [WARN] TorqueInstance - -Current Num Active Connections=40
> > > [WARN] TorqueInstance - -Current Num Idle Connections=0
> > > [WARN] TorqueInstance - -Max Active =100
> > > [WARN] TorqueInstance - -Max Idle =8
> > > [WARN] TorqueInstance - -Max Wait =500
> > > [WARN] TorqueInstance - -Current Num Active Connections=39
> > > [WARN] TorqueInstance - -Current Num Idle Connections=2
> > > [WARN] TorqueInstance - -Max Active =100
> > > [WARN] TorqueInstance - -Max Idle =8
> > > [WARN] TorqueInstance - -Max Wait =500
> > >
> > > As you can see, the number of connections reported by the pool is not
> > > even close to the number connections reported by the database. ToddC
> > >
> > > Also we are getting an exception during the test:
> > > java.sql.SQLException: Attempted to use Connection after closed() was
> > > called. at
> > >
> >
>
org.apache.commons.dbcp.cpdsadapter.ConnectionImpl.assertOpen(ConnectionImpl
> > > .java:140)
> > > at
> > >
> >
>
org.apache.commons.dbcp.cpdsadapter.ConnectionImpl.getMetaData(ConnectionImp
> > > l.java:253)
> > > at org.apache.torque.util.Transaction.rollback(Transaction.java:193)
> > > at
> > > org.apache.torque.util.Transaction.safeRollback(Transaction.java:232)
> > > at com.concur.om.base.BaseCtReportEntry.save(Unknown Source)
> > >
> > > After this exception occurs, I receive no more output as shown above.
> > > The system appears deadlocked. I can send a stack dump (Ctrl-Break on
> > > Wintel machines). The stack dump is pretty interesting as it shows
> > > where the contention is within dbcp and pool system but I don't know
> > > if it will help debug this leak problem (e.g. only one thread can
> > > create a db connection
> > at
> > > time because the connection to the db is created during makeobject).
> > > Let
> > me
> > > know if anyone is interested in seeing the dump.
> > >
> > > This problem is critical for us (I had advocated moving to new Torque
> > > and DBCP and now am in a tough spot with this problem). I will
> > > continue to debug what I can and can apply patches fairly easily and
> > > run them.
> > >
> > > Thanks for any timely help
> > > Todd Carmichael
> > >
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> > >
> >
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