NEW ISSUE -- WS-AT: Volatile amnesia

[Alastair Green <alastair.green@choreology.com>]

Protocol:  WS-AT
 
Artifact:  spec
 
Draft:  AT specification WS 10
 
Link to the document referenced:

http://docs.oasis-open.org/ws-tx/wstx-wsat-1.1-spec-wd-10.pdf


Section and PDF line number:  Section 10,  CV and P state tables

 
Issue type: design
 

Related issues: 081


Issue description:
 

Following resolution to 081, we are left with two related sub-issues, as 
discussed in 24/8 TC. This issue aims to scoop these up in one go.


1a. CV now transits directly to None whenever machine Forgets. This 
enabled removal of All Forgotten row. P table has the same feature 
(transition to None results from All Forgotten, which is implicitly 
generated by Forget action). I see no reason not to align P table with 
this approach.

1b. P table is also inconsistent, internally, and with regard to CV 
table, in that actions which should lead to None do not say "Forget" 
except in the case of Commit Decision/Prepared Sucess.

2. Resolution of 081 failed to address the fact that volatile 
relationships can transit to none through deliberate or accidental 
amnesia (volatile participants are defined as ones which are not 
guaranteed to receive the outcome, and either end could therefore decide 
to wipe its records of the transaction, or could have them wiped by a 
crash without subseqent recovery). This is not addressed in the state 
tables, which only allow transition to None through 
transmission/reception of the past participle messages.


Proposed resolution:
 
1. Relabel P table row All Forgotten as "Read Only Decision" and change 
the Committing/Aborting columns in that row to "N/A".

2 Option A. All P table cells that cause a Send X, which then leads 
(directly/indirectly) to None, should contain a final action Forget, and 
should uniformly show a state transition "None". E.g. "Send Read Only 
and Forget"; "Send Aborted and Forget".

2 Option B. Remove action Forget from CV and P tables, and ensure that 
all final actions which lead to None show that explicitly without 
indirection through All Forgotten (as per 081 and resolution of this 
issue, 1. above). This would be more consistent with resolution of this 
issue, 3. below.

3. Add a new row to both CV and P tables, following Max's suggestion, 
called "Volatile Forgotten". All cells are "N/A" apart from 
Committing/Aborting. These should read  "None".

[NOTE: Volatile Forgotten (which will not be formally defined, in line 
with a prior TC decision) is taken for the purposes of this resolution 
to mean: "The coordinator view ! participant implementation is free to 
forget a bilateral relationship where the participant is volatile, 
either through positive action or post-crash amnesia, once the 
relationship is successfully prepared, as there is no obligation to 
deliver the outcome to volatile participants. The action or fact of 
forgetting in this way is represented by the internal event Volatile 
Forgotten." For the avoidance of doubt, this definition is not part of 
the proposed resolution.]