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From Stephen Westbom <swest...@yahoo.com>
Subject RE: [dbcp] RE: How to debug closed connection problems
Date Fri, 17 Jan 2003 18:00:45 GMT
Yep, that is what I meant, I saw the examples for Tomcat.  I have to use it in
Weblogic though because I am using it from within a session bean.  I haven't
used the jdbc2pool.


--- Linda Steckel <Linda@FriedWire.com> wrote:
> <Have you worked on using dbcp through JNDI yet with an object factory?  I
> haven't seen any uses of it that way.  That would make it as convenient as
> Weblogic's implementation of pooling.>
> 
> I think? that's what I'm doing.  I have the connections set up in the
> server.xml.  Then I retrieve the jndi context and grab the datasource.  I do
> a query or two and then close the statements, resultsets and connection.
> The problem with debugging is that I don't really understand this very well.
> And I don't really understand what the difference is between dbcp and the
> jdbc2pool which I'm not using.  Is this what you meant?
> 
> 
> -----Original Message-----
> From: Stephen Westbom [mailto:swestbom@yahoo.com]
> Sent: Friday, January 17, 2003 10:41 AM
> To: Jakarta Commons Users List
> Subject: RE: [dbcp] RE: How to debug closed connection problems
> 
> 
> Thanks for the help on where to send bugs.  I can tell you one thing, dbcp
> isn't ready for prime time for multiple result sets (at least using Sybase).
> 
> Have you worked on using dbcp through JNDI yet with an object factory?  I
> haven't seen any uses of it that way.  That would make it as convenient as
> Weblogic's implementation of pooling.
> 
> 
> --- Linda Steckel <Linda@FriedWire.com> wrote:
> > In summary, we are already using Weblogic server with weblogic connections
> > sucessfully.  We haven't had any pooling problems and it's been several
> > years of constant use.  As a seperate project, I'm trying to convert out
> > webservers to Tomcat and use the dbcp connection pooling (We'd like to use
> > open source code instead of commercial).  Is there anyone out there using
> > Tomcat with dbcp for heavily used commercial applications?  So, same
> > database setup/same hardware, different software.  I already limit the
> pool
> > to 1 and test.  It's hard to test because the problem sometimes takes a
> day
> > or two to appear and then there's no way to discover what happened.
> > Sometimes it just occurs with in minutes.  Either way, I can't tell what
> has
> > happened.  One thing that I am realizing is that the problem doesn't occur
> > in one set of servlet/classes but does occur in another.  So, my next step
> > is to try to see what is different between the two sets of code that use
> the
> > connections and perhaps that will give me a clue.  Again, the same code
> that
> > doesn't create connections problems in Weblogic.  I checked with the
> network
> > guy, we don't have network timeouts and if that were the problem I'd see
> > that in Weblogic as well I think.
> >
> > I am new to this group too - I think you would post a bug to the
> developer's
> > email group.  This is the user's email group.
> >
> > -----Original Message-----
> > From: Stephen Westbom [mailto:swestbom@yahoo.com]
> > Sent: Friday, January 17, 2003 10:06 AM
> > To: Jakarta Commons Users List
> > Subject: Re: [dbcp] RE: How to debug closed connection problems
> >
> >
> > Are you using weblogic defined connections?  If so, you are getting WL's
> > wrapper classes, not dbcp wrappers.  If not.
> >
> > Can you see the socket connections to the database server?  If the
> database
> > thinks they are irretrievable that probably means that it cannot
> communicate
> > with the client but the socket is still there on its end.
> >
> > You probably need to check for some network based timeout.  If this is the
> > problem you should be able to make it repeatable by limiting the pool to 1
> > connection, creating the connection on pool instantiation and then
> waiting.
> >
> > P.S.  I am new to the user group what email address am I supposed to use
> to
> > post bugs?
> >
> >
> > --- Linda Steckel <Linda@FriedWire.com> wrote:
> > > Thanks for the info.  It doesn't look like your fixes got posted?
> > > Unfortunately, none of the situations described are the problem.  We use
> > > Oracle 8i.  We also have weblogic running and it has no problems with
> the
> > > connection pooling, so I think there's something strange going on.  Also
> > it
> > > "appears" that the connections are not actually closed.  They still
> exist
> > > but the dpcp pooling thinks they are closed and return an error.
> > >
> > > -----Original Message-----
> > > From: Stephen Westbom [mailto:swestbom@yahoo.com]
> > > Sent: Tuesday, January 14, 2003 6:34 PM
> > > To: Jakarta Commons Users List
> > > Subject: RE: How to debug closed connection problems
> > >
> > >
> > >
> > > I put some fixes in as well and reported them.  The ones I found are in
> > the
> > > result set wrapper class's close() and next() methods.  The code should
> > > check for null in the wrapped result set because the getResultSet()
> method
> > > that calls the result set wrap
> > > per class's constructor in the statement object can have a null result
> set
> > > reference.
> > > But back to your problem.  There is probably an idle connection timeout
> in
> > > the DB2 configuration, check with your DBA.  The pool would have no way
> of
> > > knowing that its underlying socket connection is dead until it pings the
> > > connection on checkout (expens
> > > ive) or you try to use it.
> > > The other possibility for a dead socket is a firewall or router table
> > > timeout of the socket connection.  Check with your networking or
> security
> > > people.
> > > If either one of these is the problem you will need to set the idle
> > > connection timeout accordingly.
> > >  Linda Steckel <Linda@FriedWire.com> wrote:Frank,
> > >
> > > I'd love to have your fixes.
> > >
> > > I am having a similar problem with the connections getting closed
> > > unexpectedly after the same code runs for hours. I'm using Oracle 8i. If
> I
> > > look at the database, it appears that they are connections open (but
> > > irretrievable?), yet the error says "Connection closed". I haven't been
> > > able to figure out what is going on.
> > >
> > > Thanks
> > > Linda
> > >
> > > -----Original Message-----
> > > From: lawlor@athensgroup.com [mailto:lawlor@athensgroup.com]
> > > Sent: Tuesday, January 14, 2003 4:49 PM
> > > To: commons-user@jakarta.apache.org
> > > Subject: How to debug closed connection problems
> > >
> > >
> > > I'm looking for some suggestions on how to debug a problem my
> application
> > > is having with closed connections using the commons connection pooling
> > > (the REAL connection gets closed out from under the PoolableConnection).
> > >
> > > I am running JDBC from a Window's client to either a local DB2 or a
> remote
> > > DB2
> > > database (Ver 7.2.4) from a Tomact web app.
> > >
> > > I got the commons dbcp and pool source and instrumented it with some
> > > printouts and discovered a couple of bugs in that code (very scarry ones
> > > - this code is not ready for prime time). However, I am still getting
> > > the underlying JDBC Connection closed out from under the
> > PoolableConnection.
> > >
> > > I instrumented all the code in the commons code where there is a
> > > _conn.close() and all the code calling any of this code and (with my
> > fixes)
> > > I no longer see the pooling code doing the close of the real connection.
> > >
> > > I added DriverManager.setLogWriter() to get added information and it
> does
> > > seem to show a Connection close just before the application tries to
> close
> > > the PoolableConnection, but unfortunately it doesn't give any traceback
> to
> > > see who the culprit is.
> > >
> > > My application only deals with the PoolableConnections so I don't see
> how
> > it
> > > can be doing the close of the real connection.
> > >
> > > Does anyone have any suggestions on how I can determine what is doing
> this
> > > real connection close????
> > >
> > > Thanks,
> > > -- Frank
> > >
> > >
> > > --
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> > >
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> > >
> > >
> > >
> > > --
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> > >
> > >
> > >
> > > ---------------------------------
> > > Do you Yahoo!?
> 
=== message truncated ===


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