public static CopyModeResult CreateCopyNoneResult(SharedProgressVectorEntry sharedProgressVectorEntry)
{
return(new CopyModeResult
{
SharedProgressVectorEntry = sharedProgressVectorEntry,
SourceStartingLsn = LogicalSequenceNumber.InvalidLsn,
TargetStartingLsn = LogicalSequenceNumber.InvalidLsn,
CopyMode = CopyMode.None
});
}
public static CopyModeResult CreatePartialCopyResult(
SharedProgressVectorEntry sharedProgressVectorEntry,
LogicalSequenceNumber sourceStartingLsn,
LogicalSequenceNumber targetStartingLsn)
{
return(new CopyModeResult
{
SourceStartingLsn = sourceStartingLsn,
TargetStartingLsn = targetStartingLsn,
CopyMode = CopyMode.Partial,
SharedProgressVectorEntry = sharedProgressVectorEntry
});
}
public static CopyModeResult CreateFullCopyResult(
SharedProgressVectorEntry sharedProgressVectorEntry,
FullCopyReason reason)
{
Utility.Assert(reason != FullCopyReason.Invalid, "reason!= FullCopyReason.Invalid");
return(new CopyModeResult
{
SharedProgressVectorEntry = sharedProgressVectorEntry,
SourceStartingLsn = LogicalSequenceNumber.InvalidLsn,
TargetStartingLsn = LogicalSequenceNumber.InvalidLsn,
CopyMode = CopyMode.Full,
FullCopyReason = reason
});
}
public static CopyModeResult CreateFalseProgressResult(
long lastRecoveredAtomicRedoOperationLsnAtTarget,
SharedProgressVectorEntry sharedProgressVectorEntry,
LogicalSequenceNumber sourceStartingLsn,
LogicalSequenceNumber targetStartingLsn)
{
if (lastRecoveredAtomicRedoOperationLsnAtTarget > sourceStartingLsn.LSN)
{
// Atomic Redo operations cannot be undone in false progress.
// So resort to full copy
return(CreateFullCopyResult(sharedProgressVectorEntry, FullCopyReason.AtomicRedoOperationFalseProgressed));
}
return(new CopyModeResult
{
SourceStartingLsn = sourceStartingLsn,
TargetStartingLsn = targetStartingLsn,
CopyMode = CopyMode.FalseProgress | CopyMode.Partial,
SharedProgressVectorEntry = sharedProgressVectorEntry
});
}
internal static CopyModeResult FindCopyMode(
CopyContextParameters sourceParamaters,
CopyContextParameters targetParameters,
long lastRecoveredAtomicRedoOperationLsnAtTarget)
{
var result = FindCopyModePrivate(sourceParamaters, targetParameters, lastRecoveredAtomicRedoOperationLsnAtTarget);
if (result.CopyMode.HasFlag(CopyMode.FalseProgress))
{
string failureMsg = string.Format(
"(sourceStartingLsn is expected to be lesser or equal to targetStartingLsn). Source starting lsn : {0}, target starting lsn :{1} ",
result.SourceStartingLsn.LSN,
result.TargetStartingLsn.LSN);
if (!ValidateIfDebugEnabled(
result.SourceStartingLsn <= result.TargetStartingLsn,
failureMsg))
{
SharedProgressVectorEntry failedValidationResult = new SharedProgressVectorEntry
{
SourceIndex = result.SharedProgressVectorEntry.SourceIndex,
TargetIndex = result.SharedProgressVectorEntry.TargetIndex,
SourceProgressVectorEntry = result.SharedProgressVectorEntry.SourceProgressVectorEntry,
TargetProgressVectorEntry = result.SharedProgressVectorEntry.TargetProgressVectorEntry,
FullCopyReason = FullCopyReason.ValidationFailed,
FailedValidationMessage = failureMsg
};
return(CopyModeResult.CreateFullCopyResult(
failedValidationResult,
FullCopyReason.ValidationFailed));
}
}
return(result);
}
internal static SharedProgressVectorEntry FindSharedVector(
ProgressVector sourceProgressVector,
ProgressVector targetProgressVector)
{
// Initialize indices
var sourceIndex = sourceProgressVector.vectors.Count - 1;
var targetIndex = targetProgressVector.vectors.Count - 1;
Utility.Assert(
targetProgressVector.vectors[targetIndex].Epoch.DataLossNumber <= sourceProgressVector.vectors[sourceIndex].Epoch.DataLossNumber,
"targetDataLossNumber ({0}) <= sourceDataLossNumber ({1})",
targetProgressVector.vectors[targetIndex].Epoch.DataLossNumber, sourceProgressVector.vectors[sourceIndex].Epoch.DataLossNumber);
SharedProgressVectorEntry progrssVectorTrimmedResult = new SharedProgressVectorEntry()
{
FullCopyReason = FullCopyReason.ProgressVectorTrimmed
};
do
{
bool decrementIndexSuccess = DecrementIndexUntilLeq(
ref targetIndex,
targetProgressVector,
sourceProgressVector.vectors[sourceIndex]);
if (!decrementIndexSuccess)
{
return(progrssVectorTrimmedResult);
}
decrementIndexSuccess = DecrementIndexUntilLeq(
ref sourceIndex,
sourceProgressVector,
targetProgressVector.vectors[targetIndex]);
if (!decrementIndexSuccess)
{
return(progrssVectorTrimmedResult);
}
} while (sourceProgressVector.vectors[sourceIndex] != targetProgressVector.vectors[targetIndex]);
var sourceProgressVectorEntry = sourceProgressVector.vectors[sourceIndex];
var targetProgressVectorEntry = targetProgressVector.vectors[targetIndex];
// WITHOUT MINI RECONFIG ENABLED, it is not possible for the target to make VALID progress TWICE from the shared epoch
// Note that this check is only valid in the absence of dataloss and restore.
// E.g
/*
* Target Replica Copy Context: 131383889527030885
* TargetLogHeadEpoch: 0,0 TargetLogHeadLsn: 0 TargetLogTailEpoch: 131383889406148342,64424509440 TargetLogTailLSN: 73
* SourceLogHeadEpoch: 0,0 SourceLogHeadLsn: 0 SourceLogTailEpoch: 131383889406148342,68719476736 SourceLogTailLSN: 68
* Target ProgressVector: [(131383889406148342,64424509440),73,131383889527030885,2017-05-04T16:32:22]
* [(131383889406148342,55834574848),68,131383889527030885,2017-05-04T16:31:54]
* [(131383889406148342,51539607552),62,131383889416461059,2017-05-04T16:31:37]
* [(131383889406148342,47244640256),56,131383889527030885,2017-05-04T16:31:20]
* [(0,0),0,0,2017-05-04T16:29:07]
* Source ProgressVector: [(131383889406148342,68719476736),68,131383890970495929,2017-05-04T16:32:33]
* [(131383889406148342,60129542144),68,131383890970495929,2017-05-04T16:32:09]
* [(131383889406148342,51539607552),62,131383889416461059,2017-05-04T16:31:37]
* [(131383889406148342,47244640256),56,131383889527030885,2017-05-04T16:31:20]
* [(0,0),0,0,2017-05-04T16:31:33]
* LastRecoveredAtomicRedoOperationLsn: 0.
*
*
* Target Replica Copy Context: 131399770096882719
* TargetLogHeadEpoch: 0,0 TargetLogHeadLsn: 0 TargetLogTailEpoch: 131399758616683034,390842023936 TargetLogTailLSN: 374
* SourceLogHeadEpoch: 0,0 SourceLogHeadLsn: 0 SourceLogTailEpoch: 131399758616683034,395136991232 SourceLogTailLSN: 369
* Target ProgressVector:
* [(131399758616683034,390842023936),374,131399770096882719,2017-05-23T01:42:03]
* [(131399758616683034,382252089344),374,131399770096882719,2017-05-23T01:41:29]
* [(131399758616683034,377957122048),369,131399770096882719,2017-05-23T01:41:00]
* [(131399758616683034,373662154752),338,131399758632647497,2017-05-23T01:40:31]
* Source ProgressVector:
* [(131399758616683034,395136991232),369,131399758701866693,2017-05-23T01:42:19]
* [(131399758616683034,386547056640),369,131399758701866693,2017-05-23T01:41:44]
* [(131399758616683034,373662154752),338,131399758632647497,2017-05-23T01:40:31]
* LastRecoveredAtomicRedoOperationLsn: 0
*/
string failureMsg;
if (targetProgressVector.LastProgressVectorEntry.Epoch.DataLossNumber
== sourceProgressVector.LastProgressVectorEntry.Epoch.DataLossNumber &&
targetIndex < targetProgressVector.vectors.Count - 1 &&
targetProgressVector.LastProgressVectorEntry.Epoch.DataLossNumber == targetProgressVector.vectors[targetIndex].Epoch.DataLossNumber)
{
// Target replica could only have repeatedly attempted to become a
// primary without ever making progress at the shared dataloss number
// We can do "double progress check" only if there has NOT been any other data loss happening on the target after shared point. Having a differnt dataloss numbers in shared vector and target's tail
// means that target has been a valid primary and progressed in LSN until hitting a dataloss and then a very old secondary can become primary and invalidate all the progress made by the target.
var failureLsn = targetProgressVector.vectors[targetIndex + 1].Lsn;
var failureLsnIncremented = 0;
for (var n = targetIndex + 2; n <= targetProgressVector.vectors.Count - 1; n++)
{
var vector = targetProgressVector.vectors[n];
if (vector.Epoch.DataLossNumber != targetProgressVectorEntry.Epoch.DataLossNumber)
{
break;
}
if (vector.Lsn != failureLsn)
{
// Update failureLsn to ensure we don't assert if there are multiple entries for same LSN like in 2nd example above
failureLsn = vector.Lsn;
failureLsnIncremented++;
}
}
failureMsg = string.Format(
"FailureLsn incremented must be <= 1. It is {0}",
failureLsnIncremented);
if (!ValidateIfDebugEnabled(
failureLsnIncremented <= 1,
failureMsg))
{
return(new SharedProgressVectorEntry
{
SourceIndex = sourceIndex,
TargetIndex = targetIndex,
SourceProgressVectorEntry = sourceProgressVectorEntry,
TargetProgressVectorEntry = targetProgressVectorEntry,
FullCopyReason = FullCopyReason.ValidationFailed,
FailedValidationMessage = failureMsg
});
}
}
// Sanity check that source and target progress vectors are always in
// agreement upto above determined ProgressVectorEntry shared by both of them
var i = sourceIndex;
var sourceEntry = sourceProgressVectorEntry;
var j = targetIndex;
var targetEntry = targetProgressVectorEntry;
failureMsg = "sourceEntry == targetEntry";
do
{
sourceEntry = DecrementIndexUntilLsnIsEqual(ref i, sourceProgressVector, sourceEntry.Lsn.LSN);
if (i == 0)
{
break;
}
targetEntry = DecrementIndexUntilLsnIsEqual(ref j, targetProgressVector, targetEntry.Lsn.LSN);
if (j == 0)
{
break;
}
if (!ValidateIfDebugEnabled(
sourceEntry == targetEntry,
failureMsg))
{
return(new SharedProgressVectorEntry
{
SourceIndex = sourceIndex,
TargetIndex = targetIndex,
SourceProgressVectorEntry = sourceProgressVectorEntry,
TargetProgressVectorEntry = targetProgressVectorEntry,
FullCopyReason = FullCopyReason.ValidationFailed,
FailedValidationMessage = failureMsg
});
}
} while (true);
Utility.Assert(sourceProgressVectorEntry != null && targetProgressVectorEntry != null, "Source and target expected to be non null");
return(new SharedProgressVectorEntry
{
SourceIndex = sourceIndex,
TargetIndex = targetIndex,
SourceProgressVectorEntry = sourceProgressVectorEntry,
TargetProgressVectorEntry = targetProgressVectorEntry
});
}