Spontaneous abortion and resignation
of participants (PV state table changes) as proposed in the issue resolution is
consistent with the behavior detailed in the CV table.
However, spontaneous preparation is a new behavior; it is unclear
why this is useful. Further, to my knowledge, legacy resource managers do not
actually support eager preparation.
Proposed resolution:
Section 10 State tables, PV state table:
1.
Row ‘Rollback decision’, column ‘Active’:
change to ‘Send Aborted / Aborting’
2.
Row ‘All Forgotten’, column ‘Active’:
change to ‘Send ReadOnly / None’
From: Ram Jeyaraman
[mailto:Ram.Jeyaraman@microsoft.com]
Sent: Wednesday, May 31, 2006 11:53 PM
To: ws-tx@lists.oasis-open.org
Subject: [ws-tx] Issue 061 - WS-AT: Spontaneous
preparation/resignation/abortion of participant
This is identified as
WS-TX issue 061.
Please ensure follow-ups
have a subject line starting "Issue 061 - WS-AT: Spontaneous
preparation/resignation/abortion of participant".
From: Alastair Green
[mailto:alastair.green@choreology.com]
Sent: Wednesday, May 31, 2006 2:36 AM
To: ws-tx@lists.oasis-open.org
Subject: [ws-tx] NEW ISSUE -- WS-AT: Spontaneous
preparation/resignation/abortion of participant
Issue name -- WS-AT: Spontaneous
preparation/abortion/resignation of participant
PLEASE DO NOT REPLY TO THIS EMAIL OR START A DISCUSSION THREAD UNTIL THE ISSUE
IS ASSIGNED A NUMBER.
The issues coordinators will notify the list when that has occurred.
Protocol: WS-AT
Artifact: spec
Draft:
WS-AT CD 0.1 uploaded
Link to the document referenced:
http://www.oasis-open.org/apps/org/workgroup/ws-tx/download.php/17325/wstx-wsat-1.1-spec-cd-01.pdf
Section and PDF line number
Section 10, "State Tables", Coordinator View table, between ll. 503
and 504, and Participant View table following
Issue type: Design
Related issues: None
Issue Description:
PV state table appears to prohibit rollback decision in Active state, tho' CV
would accept message if sent. Same applies to ReadOnly.
Issue Details:
PV state table Row Rollback Decision, State Active, N/A -- means cannot occur.
This implies that participant can never make decision to abort until it has
received Prepare. But Expires Times Out generates spontaneous abort: it is safe
against the CV table. Not clear why P cannot abort prior to receiving Prepare.
Similarly: PV state table All Forgotten, State Active, N/A -- means cannot
occur. This implies that participant cannot go read-only until it has received
Prepare.
CV state table Row Aborted, State Active, action: Forget; state Aborting. This
cell cannot be entered if Prepare has already been sent (wd be in state
Preparing). But PV can only send if expires times out.
CV state table Read Only, State Active, action: Forget; state Active. This cell
cannot be entered: if Prepare has already been sent C would be in state
Preparing. PV cannot send Read Only in Active state..
Therefore, CV in Active state is able to accept messages that PV can never send
(Read Only) or that it can only send in a very restricted circumstance.
From the standpoint of correctness and speed of transaction resolution, there
is no argument against allowing Participants to spontaneously prepare (q.v.
Gray/Lamport, "Paxos Commit"), vote rollback, or go read-only (i.e.
to make these decisions prior to receiving Prepare).
Proposed Resolution:
Alter state tables to permit spontaneous preparation, abortion and resignation,
as per attached Word document.
If this is not accepted, the un-enterable cell (Read Only/Active) in CV needs
to be set to N/A.