Hi,
[a]
I read Dieter's proposal into two halves:
(a1)
"If a custom termination handler contains parallel activities and one
of these activities propagates a fault then all concurrent activities
in the termination handler MUST be terminated."
The semantics of terminating concurrent activities is generally covered
in section 12.6:
" ... For a parallel <forEach>, termination MUST be applied to all parallel executing
branches. ... The <sequence> and <flow> constructs MUST be terminated by terminating their behavior
and
applying termination to all nested activities currently active within
them. "
That also address Example #1 in the issue description.
(a2)
"Likewise, if a default
termination handler compensates a compensation handler instance group
and one of the compensation handler instances propagates a fault then
the other compensation handler instances of the compensation handler
instance group MUST be terminated."
I think that is not specific to termination handler, it just covers any
FCT-handlers. I think it is already cover in the general discussion
Compensation Handler Instance Groups.
At the end of "12.4.4.1. Compensation Handler Instance Groups":
If an uncaught fault occurs while executing any
compensation handler instance of the group, or if compensation
activities are terminated, then all running instances MUST be
terminated following standard WS-BPEL activity termination semantics.
All compensation handler instances of the group and compensation
handler instance groups of immediately enclosed scopes are uninstalled.
Completed compensation handler instances within a Compensation Handler
Instance Group are not subject to further compensation.
That also address Example #2 in the issue description.
[b]
About Danny's question: "... can't
find any such thing, but it seems "obvious" to me that we should have
said it. ...", I found something similar (not sure whether it is
precise and board enough to cover):
Under "12.4.4.3. Compensation within FCT-Handlers":
...
A fault in a fault handler MUST cause all running contained activities
to be terminated. ...
...
A
compensation handler that faults (“internal
fault”) will undo its partial work by compensating all scopes immediately enclosed by the root scope according
to the fault
handler of the root scope. If such a fault handler is not specified
explicitly,
partial work will be compensated in the default order (see section REF _Ref133840370 \h 12.5.2.
Default Compensation Order).
This approach can be used to provide all or
nothing semantics for compensation handlers. After the partial work is
undone,
the compensation handler MUST be uninstalled. The fault MUST be
propagated to
the caller of the compensation handler. This caller is a default
FCT-handler of
the enclosing scope or a compensation activity contained within a
user-defined
handler.
...
A fault inside a termination handler MUST NOT be not propagated to
the
enclosing scope (see section REF _Ref147214390 \h
12.6 Termination Handlers).
Other than that, all of the statements about fault handlers apply to
termination handlers as well.
Thanks!
Regards,
Alex Yiu
Danny van der Rijn wrote:
Does this need to be generalized to not just parallel constructs? Do
we ever say, for instance, that a fault reaching a FCT-Handler MUST
terminate all running activities in the termination handler? I can't
find any such thing, but it seems "obvious" to me that we should have
said it.
That would take care of your cases, too, wouldn't it?
ws-bpel issues list editor wrote:
This issue has been added to the wsbpel issue list with a status
of "received".
The status will be changed to "open" if a motion to open the issue is
proposed and that
motion is approved by the TC. A motion could also be proposed to close
it without
further consideration. Otherwise it will remain as "received".
The issues list is posted as a Technical Committee document to
the OASIS
WSBPEL TC pages
on a regular basis. The current edition, as a TC document, is the most
recent version of the document entitled in the "Issues" folder of the WSBPEL
TC document list
- the next posting as a TC document will include this issue.
The list editor's working copy, which will normally include an issue
when it is announced, is available at this
constant URL.
Issue - R27 - Faults and Parallelism in Termination Handlers
Status: received
Date added: 30 Oct 2006
Date submitted: 27 October 2006
Submitter: Dieter
Koenig
Description: Consider the following examples of parallelism
inside of
termination handlers.
Example 1. Assume that a custom termination handler contains a
parallel
forEach activity or a flow activity. In either case, assume that
multiple concurrent branches are active. If one branch faults, the
specification does not tell whether the other branches are allowed to
complete or terminated.
Example 2. Assume that a default termination handler that
compensates a
compensation handler instance group. If one compensation handler
instance faults, the specification does not tell whether the other
compensation handler instances are allowed to complete or terminated.
Submitter's proposal: Add the following to the end of
section
12.6.:
"If a custom termination handler contains parallel
activities and one of
these activities propagates a fault then all concurrent activities in
the termination handler MUST be terminated. Likewise, if a default
termination handler compensates a compensation handler instance group
and one of the compensation handler instances propagates a fault then
the other compensation handler instances of the compensation handler
instance group MUST be terminated."
Changes: 30 Oct 2006 - new issue
To comment on this issue (including whether it should be
accepted), please follow-up to this announcement on the
list (replying to this message should
automatically send your message to that list), or ensure
the subject line as you send it starts "Issue - R27 -
[anything]" or is a reply
to such a message. If you want to formally propose a resolution to an
open issue, please start the subject line "Issue - R27 - Proposed
resolution", without any Re: or similar.
To add a new issue, see the issues procedures document
