Coordinator:
DEFINITIONS
LOCKS c
USING c: Handle =
BEGIN
Object:
TYPE =
MONITORED
RECORD [
transID: AlpineEnvironment.TransID ← TRASH, --immutable--
beginRecord: AlpineInternal.LogRecordID ← AlpineInternal.nullLogRecordID, --immutable--
state: State ← active,
increases monotonically from active to complete
outcome: Outcome ← unknown,
Changes to abort or commit during state transition collecting -> completing.
finishInProgress:
BOOL ←
FALSE,
A process that sets this TRUE is responsible for finishing the transaction.
aWorkerBecameReady:
BOOL ←
FALSE,
TRUE iff some worker returns "ready" from WorkerPrepare call.
workers: WorkerHandle ←
NIL,
Elements added only when state = active.
resultsReturned:
CONDITION,
Finish process waits here for remote calls to return, or for timeout
in order to delay sending new calls.
forceRecord: AlpineInternal.LogRecordID ← AlpineInternal.nullLogRecordID,
ID of log record following last-written coordinator log record
extras:
REF CoordinatorExtras.Info ←
NIL,
Extra info about the coordinator. Right now just the RName of the caller.
next: Handle ← nullHandle
CoordinatorMap data structure
];
Handle: TYPE = REF Object;
nullHandle: Handle = NIL;
State: TYPE = {active, collecting, completing, complete};
Outcome: TYPE = AlpineEnvironment.Outcome --{abort, commit, unknown}--;
WorkerObject:
TYPE =
RECORD [
worker: AlpineImport.Handle, --immutable--
state: WorkerState ← active, --increases monotonically from active to complete--
communicationTrouble: BOOL ← FALSE,
callInProgress: Call ← none, --communication in progress with worker--
resultsOfMostRecentCall: Results ← [none, none[]],
timeForNextCall: BasicTime.
GMT ←
TRASH,
meaningful only if communicationTrouble
lastPrepareResult: Results ← [none, none[]],
lastFinishResult: Results ← [none, none[]]
];
WorkerHandle: TYPE = LIST OF WorkerObject;
WorkerState: TYPE = { active, ready, complete };
Call: TYPE = { none, prepare, finish };
Results:
TYPE =
RECORD [
communicationError: CommunicationError,
body:
SELECT call: Call
FROM
none => [],
prepare => [prepareResult: AlpineEnvironment.WorkerState],
finish => []
ENDCASE
];
CommunicationError:
TYPE = { none, bindingFailed, callFailed, busy };
bindingFailed means that no call was made
callFailed means that call may or may not have been made
busy is equivalent to callFailed, but retrying is more likely to succeed.
Format of persistent coordinator state.
Note that coordinatorBegin and coordinatorComplete log records contain no information
other than the transaction ID, so we don't define structures for them here.
RegisterWorkerLogRep:
TYPE =
MACHINE
DEPENDENT
RECORD [
worker: StrBody];
CompletingLogRep:
TYPE =
MACHINE
DEPENDENT
RECORD [
outcome: AlpineEnvironment.CommitOrAbort];
StrBody:
TYPE =
MACHINE
DEPENDENT
RECORD [
length: CARDINAL ← 0, maxLength: CARDINAL ← RPC.maxShortStringLength,
text: PACKED ARRAY[0..RPC.maxShortStringLength) OF CHAR];
END.
CHANGE LOG.
Edited on June 29, 1984 10:31:34 am PDT, by Kupfer
changes to: Coordinator: add an "extras" field to the Coordinator Object. This lets up keep things like user RName (and easily change what we keep), though at some point the extras should get merged back into the Object definition proper.