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Subject: NEW ISSUE -- WS-AT: Spontaneous preparation/resignation/abortionof 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. |
2006-05-30.WS-AT.Tables.spontaneous.doc
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