[Spread-users] 'Connection closed by spread' ...

Jim Vickroy Jim.Vickroy at noaa.gov
Sat Sep 4 09:55:15 EDT 2004


Thanks for your response, Ryan.

I did not make it clear in my original posting, that these are publishing
errors -- not subscriber errors.  The errors are being trapped by try-catch
blocks wrapping publishing requests.

Most of the publishers are also subscribers to the same message group (they
must be), but each subscriber operates in its own dedicated thread that does
nothing but receive and queue messages for subsequent processing.  I doubt
the receiving/queuing thread is not keeping up with the publishers
especially since the burst rate is only on the order of 10 messages per
second for one second.  The applications keep rather detailed logs of the
messages received/published, and I see no evidence of any subscriber failing
to keep up with the publishing rate.

It is curious, however, that the one publisher which is not also a (Spread)
subscriber is the only component that, so far, has not experienced a
publishing error.  This component does have a receiver thread, but it is
monitoring a simple socket connection for message traffic.

That said, I am a novice user of Spread and certainly may have an
implementation problem; it is just not clear what is wrong.

I will ask our administrator to upgrade to the current, stable version of
Spread.


-----Original Message-----
From: spread-users-admin at lists.spread.org
[mailto:spread-users-admin at lists.spread.org]On Behalf Of Ryan Caudy
Sent: Friday, September 03, 2004 8:54 PM
To: Jim Vickroy
Cc: SPREAD-USERS
Subject: Re: [Spread-users] 'Connection closed by spread' ...


Hi,

This error is usually caused by a failure to receive by clients to
Spread.  If your clients let more than a certain number of messages,
1000 with a "vanilla" Spread, pile up at the daemon without receiving
them, then Spread will disconnect them with that error code.

You may want to look at past posts on this list about flow control.

Also, on a side note, I would encourage you to use the most recent
stable release of Spread.

Cheers,
Ryan


On Fri, 3 Sep 2004 12:12:54 -0600, Jim Vickroy <jim.vickroy at noaa.gov> wrote:
> ... is the error that is happening more frequently than desirable -- about
> once every 1000 publishing attempts.
>
> Could someone suggest a way to reduce this error rate (at least by a
factor
> of 10)?
>
> The platform:
>         Spread: v 3.17.01 (20 June 2003)
>         Spread Host: RedHat Workstation, Kernel: 2.4.21-4.EL
>         Client Host: Microsoft Windows 2000 Server
>         Client Software: Python v 2.3.3
>
> The use case:
>         Messages are published in bursts at 1-minute intervals.
>         Each burst of messages comprises 5-10 messages; each message is
generated
> by a distinct process.
>         Each message is about 100 bytes.
>         Publication service type is set to spread.SAFE_MESS.
>
> Thanks,
>
> -- jv
>
> _______________________________________________
> Spread-users mailing list
> Spread-users at lists.spread.org
> http://lists.spread.org/mailman/listinfo/spread-users
>



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Ryan W. Caudy
<rcaudy at gmail.com>
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Bloomberg L.P.
<rcaudy1 at bloomberg.net>
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[Alumnus]
<caudy at cnds.jhu.edu>
Center for Networking and Distributed Systems
Department of Computer Science
Johns Hopkins University
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