SOLVED RE: Tomcat 4.0.6 leaving CLOSE_WAIT sockets

[Dan Higgins <Da...@austin.rr.com>]

Hi again,

It looks like it was a bug in my JDBC driver.  Sorry to doubt you marvelous
Tomcat developers of the world.

Cheers,
-Dan


> -----Original Message-----
> From: Dan Higgins [mailto:DanHiggins@austin.rr.com]
> Sent: Saturday, February 01, 2003 6:59 PM
> To: Tomcat-Dev
> Subject: RE: Tomcat 4.0.6 leaving CLOSE_WAIT sockets
>
>
> Hi Again,
>
> This is not all Tomcat's fault. I have narrowed it down to JSP's
> that actually make a JDBC connection.
>
> For static (.html) files and JSP's that don't connect to a db,
> the CLOSE_WAIT problem does NOT seem to occur.
>
> I know that EJB's would be the proper way to access persistent
> data from JSP's, but for this particular site I don't have that luxury.
>
> I suspect this problem stems from all connector threads using a
> single java.sql.Connection object stored in the app context. If I
> wanted each thread to have its own Connection, how could I do
> that?  If it's OK to use one Connection object for an entire
> webapp, then I'll check for bugs in my JDBC driver...
>
> IMHO, if this is NOT a bug in my JDBC driver, then it probably
> really is a problem with Tomcat -- sockets simply shouldn't be
> left in CLOSE_WAIT by an application.
>
> Thanks,
> -Dan
>
>
> > -----Original Message-----
> > From: Dan Higgins [mailto:DanHiggins@austin.rr.com]
> > Sent: Saturday, February 01, 2003 4:13 PM
> > To: Tomcat-Dev
> > Subject: Tomcat 4.0.6 leaving CLOSE_WAIT sockets
> >
> >
> > Hi,
> >
> > I have a script which can burst any number of async socket
> > connections to Tomcat from a remote host. With it, I can get
> > every available connector processor thread to become busy at
> > once. At that point, Tomcat simply refuses any new socket
> > connections at all.
> >
> > Ok, this is to be expected. But the problem is, ALL the threads
> > seem to leave their sockets in the CLOSE_WAIT state, never
> > actually closing them. Tomcat then seems to refuse any new
> > connections until it is restarted.
> >
> > This is an issue because I am seeing it on a production server
> > with maxProcessors set to 600. It could be a targeted DoS attack,
> > or it could just be huge spikes in load at certain times. Either
> > way, Tomcat is not faring very well.
> >
> > This has been driving me batty for about a week now. Any advice
> or ideas?
> >
> > (Tomcat 4.0.6, Windows 2000 Server SP3, Sun JDK 1.4.1_01)
> >
> > -Dan


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