I enclose an attachment (.jar) that should be placed in the lib of your turbine-app. (the name is 0_pool_patch.jar just to make sure that tomcat will load it before the turbine.jar since the names of the classes are the same).
I also include the following simple code for a screen class and a velocity
template.
Whenever you call this screen you will get a list of stack traces indicating
a
NullPointerException that was only created in order to capture the stack
trace
(there is a more elegant way I think, but this works fine also). If you
follow the stack
trace you will see the point in your code that requested this connection
(and obviously
did not release it).
Screen class code:
import org.apache.turbine.modules.screens.*;
import org.apache.turbine.util.RunData;
import org.apache.velocity.context.Context;
import org.apache.turbine.modules.*;
import org.apache.turbine.util.*;
import org.apache.turbine.services.*;
import java.util.*;
import org.apache.turbine.services.cache.*;
import org.apache.turbine.services.db.*;
import org.apache.turbine.util.db.pool.*;
import java.io.*;
import java.sql.*;
public class PoolInfo extends VelocityScreen {
static boolean logsql = false;
static PrintStream ps = null;
protected void doBuildTemplate(RunData data, Context ctx) throws
java.lang.Exception {
TurbinePoolBrokerService pbs =
(TurbinePoolBrokerService)TurbineServices.getInstance().
getService(PoolBrokerService.SERVICE_NAME);
Map pools = pbs.getRegisteredPools();
ConnectionPool cp = (ConnectionPool)
pools.get(TurbinePoolBrokerService.DEFAULT);
if ( cp == null )
return;
ctx.put("cp", cp);
// put a thread array to display also running threads
Thread t[] = new Thread[Thread.activeCount()];
int count = Thread.enumerate(t);
ctx.put("threads", new Vector(Arrays.asList(t)));
}
}
A simple velocioty code in a .vm file to display:
<table border=0>
<th colspan=2> Connection Pool Runtime Information</th>
<!--Instance Director Configuration-->
<tr><td>Available :</td><td>$cp.NbrAvailable</td></tr>
<tr><td>Checked out:</td><td>$cp.NbrCheckedOut</td></tr>
<tr><td>Total:</td><td>$cp.TotalCount</td></tr>
<tr><td colspan=2 align=left><b>Active Connections</b></td></tr>
#foreach ($val in $cp.Callers)
<tr><td colspan=2><hr noshade size=1></td></tr>
<tr><td nowrap><b>Connection $velocityCount:</b></td><td><font
face=courier>$val</font></td></tr>
#end
</table>
<p>
<table border=0>
<tr>
<th colspan=7 align=left>Active threads</th>
</tr>
<tr>
<td><b>a/a</b></td>
<td><b>Name</b></td>
<td><b>Priority</b></td>
<td><b>Alive?</b></td>
<td><b>Daemon?</b></td>
<td><b>Thread Group</b></td>
</tr>
#foreach ($val in $threads)
<tr>
<td nowrap>$velocityCount</td>
<td nowrap>$!val.Name</td>
<td nowrap>$!val.Priority</td>
<td nowrap>$!val.isAlive()</td>
<td nowrap>$!val.isDaemon()</td>
<td nowrap>$!val.ThreadGroup.Name</td>
</tr>
<tr><td colspan=7><hr size=1 noshade color=$skin.Bg1></td></tr>
#end
</table>
Hope this helps
(If you want the actual code in the .jar file i can also send it)
Costas
----- Original Message -----
From: "Bob Swerdlow" <[EMAIL PROTECTED]>
To: "Turbine Users List" <[EMAIL PROTECTED]>
Sent: Thursday, March 14, 2002 5:06 PM
Subject: Re: DB Pooling and Processes
> Costas - many thanks. I've dropped the number of connections to 35 and
> things seem to be behaving. Your tool for finding leaks sounds very
> useful - please send it along.
>
> - Bob
>
> ----- Original Message -----
> From: "Costas Stergiou" <[EMAIL PROTECTED]>
> To: "Turbine Users List" <[EMAIL PROTECTED]>
> Sent: Thursday, March 14, 2002 2:43 AM
> Subject: Re: DB Pooling and Processes
>
>
> > Actually, the only way to close the connection is either if you issue
> > the DBConnection.close() method explicitly from your code or restart
> tomcat.
> >
> > But there should be no problem at all when reloading your app without
> > restarting tomcat: the Connection Pool code works fine.
> >
> > We have been using this code with oracle in a production db with
thousands
> > of transactions per day and a total of >30 concurrent users (our call
> center
> > actually
> > uses a Turbine app with more than 1000 calls per day where the db
supports
> > about
> > 100,000 customer records). I have never seen more
> > than 8 concurrent open connections (although TR.props settings is set to
> 30,
> > just
> > to be sure). I have made a small alteration to the code of Connection
> > Pooling so
> > I can get at any time the number of open connections and where they were
> > requested
> > from (through a vm screen).
> > I can send you this if you are interested (it has proven very usefult
when
> > trying
> > to find leaks; in a big app the only way to do this is to track the
stack
> > when the
> > connections are requested)
> >
> > Costas
> >
> > ----- Original Message -----
> > From: "Bob Swerdlow" <[EMAIL PROTECTED]>
> > To: "Turbine Users List" <[EMAIL PROTECTED]>
> > Sent: Wednesday, March 13, 2002 9:07 PM
> > Subject: Re: DB Pooling and Processes
> >
> >
> > > Okay, thanks - I'll look at this.
> > >
> > > And, no, we're not using the OM, but rather one we spun ourselves
> (legacy
> > > stuff).
> > >
> > > Thanks for the help!
> > >
> > > ----- Original Message -----
> > > From: "Phee, Martin J (Jump Tech)" <[EMAIL PROTECTED]>
> > > To: "'Turbine Users List'" <[EMAIL PROTECTED]>
> > > Sent: Wednesday, March 13, 2002 2:01 PM
> > > Subject: RE: DB Pooling and Processes
> > >
> > >
> > > > If you have your Oracle jars in the common/lib I believe you have to
> > > restart
> > > > tomcat to make sure everything gets released since they are shared
> > across
> > > > all apps.
> > > >
> > > > Take a look at your Turbine log to make sure that you don't see any
> > errors
> > > > say that your DBConnection was finalized before being returned to
the
> > > pool.
> > > > When I started with turbine I noticed a few of them. Didn't realize
I
> > > > needed to release the connection. Newbie thing for me.
> > > >
> > > > The OM is the object model created by the TDK or Torque. Depending
on
> > > what
> > > > your using.
> > > >
> > > > -----Original Message-----
> > > > From: Bob Swerdlow [mailto:[EMAIL PROTECTED]]
> > > > Sent: Wednesday, March 13, 2002 12:53 PM
> > > > To: Turbine Users List
> > > > Subject: Re: DB Pooling and Processes
> > > >
> > > >
> > > > Yes, we are using Tomcat and it did seem to let go of the processes
> when
> > I
> > > > restarted it. However, we are running more than one project under
> > Tomcat,
> > > > not all of which access the same database, so it is unfortunate to
> have
> > to
> > > > stop them all if we need to fix one.
> > > >
> > > > I've checked the code to ensure that the connections are being
> returned
> > > and
> > > > actually added logging so I can see that when they are created and
> > > released.
> > > > That all looks fine.
> > > >
> > > > Pardon my denseness - what's the OM?
> > > >
> > > > ----- Original Message -----
> > > > From: "Phee, Martin J (Jump Tech)" <[EMAIL PROTECTED]>
> > > > To: "'Turbine Users List'" <[EMAIL PROTECTED]>
> > > > Sent: Wednesday, March 13, 2002 1:39 PM
> > > > Subject: RE: DB Pooling and Processes
> > > >
> > > >
> > > > > Are you using Tomcat? You might need to restart it also. Also,
> make
> > > sure
> > > > > you release your connections back to turbine, and close any
> statements
> > > you
> > > > > are using. Are you using the OM?
> > > > >
> > > > > -----Original Message-----
> > > > > From: Bob Swerdlow [mailto:[EMAIL PROTECTED]]
> > > > > Sent: Wednesday, March 13, 2002 12:30 PM
> > > > > To: Turbine Users List
> > > > > Subject: Re: DB Pooling and Processes
> > > > >
> > > > >
> > > > > Thanks, Ian. I'll get the number of processes and connections
into
> > > line.
> > > > >
> > > > > Any idea how can I get rid of all the old connections when I
reload
> > the
> > > > > project?
> > > > >
> > > > > Thanks,
> > > > > Bob
> > > > >
> > > > > ----- Original Message -----
> > > > > From: "Ian Huynh" <[EMAIL PROTECTED]>
> > > > > To: "Turbine Users List" <[EMAIL PROTECTED]>
> > > > > Sent: Wednesday, March 13, 2002 1:12 PM
> > > > > Subject: RE: DB Pooling and Processes
> > > > >
> > > > >
> > > > > > Bob
> > > > > > I believe Oracle uses 1 process for each connection by default
> > unless
> > > > > > you've set up Oracle to use the MTS dispatcher.
> > > > > >
> > > > > > And also by default 50 is the default max process for Oracle.
> > > > > > You can control this file by editing your INIT*.ORA file
typically
> > > found
> > > > > > in %ORACLE_HOME%\<YourSID>\pfile\init*.ora and look for the
> > > > > > entry
> > > > > >
> > > > > > PROCESSES=100
> > > > > >
> > > > > > BTW, you also need to restart your Oracle server to pick up the
> new
> > > > value.
> > > > > >
> > > > > > Since connections are pooled (Don't know much about Turbine
> Pooling)
> > > but
> > > > > > in theory, if you app uses connection wisely, you shouldn't need
> too
> > > > many
> > > > > 'physical'
> > > > > > connections. BUt that entirely depends on your concurrent load
> and
> > > > length
> > > > > > of time a connection is used by a thread in your app. You need
to
> > > load
> > > > > test your
> > > > > > app to find the right number.
> > > > > >
> > > > > > Also beware that Oracle also limits 300 open cursors by default.
> > This
> > > > > > is another area where most people also run into trouble. You
can
> > > > > > change this param in your init*.ora file as well. If you need a
> > large
> > > > > > number of connections, chances are you probl. will run into this
> > limit
> > > > as
> > > > > well.
> > > > > >
> > > > > > open_cursors = 300
> > > > > >
> > > > > >
> > > > > >
> > > > > >
> > > > > > -----Original Message-----
> > > > > > From: Bob Swerdlow [mailto:[EMAIL PROTECTED]]
> > > > > > Sent: Wednesday, March 13, 2002 10:06 AM
> > > > > > To: [EMAIL PROTECTED]
> > > > > > Subject: DB Pooling and Processes
> > > > > >
> > > > > >
> > > > > > Hi, y'all -
> > > > > >
> > > > > > Is there documentation somewhere about how to set up Oracle with
> > > Turbine
> > > > > DB
> > > > > > Pooling?
> > > > > >
> > > > > > We ran into a problem recently where we were getting "cannot get
> > > > > connection"
> > > > > > errors. I found that our TurbineProperties.Resources had:
> > > > > >
> > > > > > # The number of database connections to cache per
> ConnectionPool
> > > > > > # instance (specified per database).
> > > > > > database.default.maxConnections=3
> > > > > >
> > > > > > Since the failure happend when our code was setting up 4
> > connections,
> > > I
> > > > > knew
> > > > > > I had to change this. After a bit of web-snooping, I changed it
> to
> > > 100.
> > > > > >
> > > > > > Now we are getting this error:
> > > > > > ORA-00020: maximum number of processes (50) exceeded
> > > > > >
> > > > > > This actually happened after reloading the project a few times.
> > > > > >
> > > > > > So my questions are:
> > > > > > 1. What is an appropriate value for
> > database.default.maxConnections?
> > > > > This
> > > > > > will be a public web site with many concurrent users retrieving
> > pages
> > > > that
> > > > > > will access the database
> > > > > > 2. Do I need to coordinate the number of connections with the
> > number
> > > > of
> > > > > > Oracle processes? How do I control this in Oracle?
> > > > > > 3. Should reloading the project release all of the
connections?
> > It
> > > > does
> > > > > > not seem to have done so, however, when I restarted Tomcat,
those
> > > > > processes
> > > > > > seemed to go away.
> > > > > > 4. What else should I worry about?
> > > > > >
> > > > > > Thanks for your help!
> > > > > >
> > > > > > Bob Swerdlow
> > > > > > Chief Operating Officer
> > > > > > Transpose, LLC
> > > > > > [EMAIL PROTECTED]
> > > > > >
> > > > > >
> > > > > >
> > > > > >
> > > > > >
> > > > > >
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0_pool_patch.jar
Description: Binary data
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