[Ace-users] Re: [tao-users] LOCATION FORWARD and _is_a() loop

[Johnny Willemsen]

Hi,

Thanks for using the PRF form. I have fixed several problems related to
forwarding a few months ago. Could you try x.5.10 and see if that resolves
this problem as first step?

Regards,

Johnny Willemsen
Remedy IT
Postbus 101
2650 AC  Berkel en Rodenrijs
The Netherlands
www.theaceorb.nl / www.remedy.nl  

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> TAO VERSION: 1.5
> ACE VERSION: 5.5
> 
> HOST MACHINE and OPERATING SYSTEM:
> Intel(R) Xeon(R) CPU 5130  @ 2.00GHz
> Linux 2.6.16.21-0.8-smp #1 SMP i386 GNU/Linux
> 
> TARGET MACHINE and OPERATING SYSTEM, if different from HOST:
> COMPILER NAME AND VERSION (AND PATCHLEVEL):
> gcc version 3.4.3
> 
> DOES THE PROBLEM AFFECT:
>     COMPILATION?
>         No.
>     LINKING?
>         No.
>     EXECUTION?
>         Yes.
> 
> SYNOPSIS:
> Location Forward and _is_a seem to loop over two hosts
> 
> DESCRIPTION:
> Here is the setup:
> 
> Two hosts, both basically running the same set of applications (A
> bunch of CORBA-servers and clients). One of the CORBA-servers
> running on both hosts is a management and control application (from
> now on: "mac-server") which clients can use to retrieve status-info 
> about the whole system.
> 
> The mac-server is implemented in a way that lets you retrieve
> status info about any of the two physical machines via any of the
> two mac-servers. (That means you can ask mac-server on host A about
> the status of the application on host B, and vice versa) Both
> mac-servers offer the same CORBA interface. If you ask one about the
> state of the other, it will internally try to resolve the object
> reference to its peer mac-server and ask him using the same
> interface that someone just used to call him. (Hope it is clear what
> I mean here)
> 
> Now, on certain conditions (which I not isolated completely yet), I
> see a loop between the two mac-servers:
> I ask server A about the status of server B and the ORB of
> mac-server on server A starts the request by sending a _is_a()
> request to server B. Server B then -- for some reason I don't
> understand -- sends a LOCATION FORWARD back to server A, which again
> sends _is_a() to server B, and so on and on and on.
> 
> After about 4500 requests in about 3 seconds time, one of the 
> mac-servers dies with segmentation fault.
> 
> My question: Is there a way to completely disable LOCATION FORWARDs
> and/or do you have any idea where this might come from?
> 
> SAMPLE FIX/WORKAROUND:
> None.
> 
> I can send the 3.5MB pcap logfile if anyone is interested.
> 
> Thanks in advance,
> Christian Fromme
> 
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