Title: RE: [ws-rx] NEW ISSUE: Is an implementation supporting a smaller max message number valid? [Re: [ws-rx] NEW ISSUE: Max message number in policy]
While I fully agree with Chris' concern, I believe nothing in the spec prevents Chris to implement exactly what he describes below:
- nothing prevents an RM destination to send back a MessageNumberRollover *before* the specified maximum (unsignedLong max) is reached (!)
In the mentioned Java context this occurrence would be so remote that even if a Source is "surprised" by a lower maximum, I'd say the overhead of recovering from the fault (meaning creating a new sequence I guess - which needs be done anyway -, and resending some message) is acceptable ...
(Also even if an implementation can't handle that we'll all die before :-)
I was about to suggest that the current MessageNumberRollover fault message could be extended to contain the maximum that has been exceeded, in case this max is smaller than the specified maximum (unsignedLong max). But it seems the Source can figure which messages have been lost in a wrap-around event just by looking at the Acknowledgement.
Jacques
-----Original Message-----
From: Christopher B Ferris [mailto:]
Sent: Thursday, July 14, 2005 3:20 PM
To: Doug Bunting
Cc: Doug Davis; ;
Subject: Re: [ws-rx] NEW ISSUE: Is an implementation supporting a smaller max message number valid? [Re: [ws-rx] NEW ISSUE: Max message number in policy]
Doug,
A Java long is signed and hence it's maximum value is
+9,223,372,036,854,775,807.
In order to support an unsigned long, you need to resort to use of
java.math.BigInteger which
is less efficient than using the primative type long. Besides that, J2ME
doesn't include java.math
so it would therefore be even more difficult to implement a WS-RM endpoint
on that platform.
Since nine quintillion is a REALLY BIG NUMBER, (yeah, yeah, 19
quintillion is an even bigger number)
we would like to propose that an endpoint could declare the maximum
MessageNumber it supported
is the maximum value of a long such that it would be possible to implement
processing of the
MessageNumber using a Java long primitive type and so that the spec could
be implemented
in a conformant manner on the J2ME platform.
It would take ~292,471,208.67 years to exhaust a sequence that was only
the size of a long
if you processed 1000 messages per second.
Most of us will be dead before the first WS-RM Sequence is exhausted even
if it is reduced
from 18 quintillion to 9 quintillion.
Cheers,
Christopher Ferris
STSM, Emerging e-business Industry Architecture
email:
blog: http://webpages.charter.net/chrisfer/blog.html
phone: +1 508 377 9295
wrote on 07/14/2005 05:32:20 PM:
> *Title*: Is an implementation supporting a smaller max message number
valid?
>
> *Description*: The existing specification includes the clause "If the
> message number exceeds the internal limitations of an RM Source or RM
> Destination ...". This allows a source or destination to handle
> unexpected failures gracefully. It does not clearly allow, require, or
> prevent the implementation to be designed or deployed with a message
> number limit. Should we support such a limitation?
>
> *Justification*: Issue below presupposes a "yes" answer to this
> question. Should decide this larger question before deciding how to
> fill gap left if the answer is "yes".
>
> *Target*: core (RM spec)
>
> *Type*: design
>
> *Proposal*: I lean toward "no" but could be convinced otherwise. If
> "no" is the answer, the specification could change to make it clear a
> WS-RM compliant implementation _must_ support the full unsigned long
> range for the message number. That likely requires conformance
> terminology not presently in the specification; this issue is not
> intended to broach the even-more-general subject of conformance clauses.
> My proposal therefore comes down to "close, no action".
>
> *Related issues*: Max message number in policy [no number yet]
>
> thanx,
> doug
>
> On 12/07/05 07:39, Doug Davis wrote:
> >
> > *Title*: Max message number in policy
> > *Description*: define a policy assertion that defines the highest
> > message number the RM destination will accept.
> > *Justification*: without knowing in advance what the highest message
> > number is the RM source may exceed it, causing the entire sequence to
be
> > terminated - when it may have been able to start a 2nd sequence to
> > continue its work. By allowing the RM source the option of
terminating
> > the sequence gracefully it can still deliver lost messages for the
> > original sequence. As it stands now, if the sequence is terminated
the
> > lost messages will not be resent.
> > *Target:* RM policy spec
> > *Proposal:* Define:
> > /wsrm:RMAssertion/wsrm:MaxMessageNumber
> > /wsrm:RMAssertion/wsrm:MaxMessageNumber@number - unsigned long
> >
> > thanks
> > -Doug
> >
