private long GetValidLogPosition(long logPosition, Epoch[] epochs, IPEndPoint replicaEndPoint, Guid subscriptionId)
{
if (epochs.Length == 0)
{
if (logPosition > 0)
{
// slave has some data, but doesn't have any epoch
// for now we'll just report error and close connection
var msg = string.Format("Replica [{0},S:{1},{2}] has positive LogPosition {3} (0x{3:X}), but does not have epochs.",
replicaEndPoint, subscriptionId,
string.Join(", ", epochs.Select(x => x.AsString())), logPosition);
Log.Info(
"Replica [{replicaEndPoint},S:{subscriptionId},{epochs}] has positive LogPosition {logPosition} (0x{logPosition:X}), but does not have epochs.",
replicaEndPoint, subscriptionId,
string.Join(", ", epochs.Select(x => x.AsString())), logPosition, logPosition);
throw new Exception(msg);
}
return(0);
}
var masterCheckpoint = _db.Config.WriterCheckpoint.Read();
Epoch afterCommonEpoch = null;
Epoch commonEpoch = null;
for (int i = 0; i < epochs.Length; ++i)
{
var epoch = epochs[i];
if (_epochManager.IsCorrectEpochAt(epoch.EpochPosition, epoch.EpochNumber, epoch.EpochId))
{
commonEpoch = epoch;
afterCommonEpoch = i > 0 ? epochs[i - 1] : null;
break;
}
}
if (commonEpoch == null)
{
Log.Error("No common epoch found for replica [{replicaEndPoint},S{subscriptionId},{logPosition}(0x{logPosition:X}),{epochs}]. Subscribing at 0. Master LogPosition: {masterCheckpoint} (0x{masterCheckpoint:X}), known epochs: {knownEpochs}.",
replicaEndPoint, subscriptionId,
logPosition, logPosition,
string.Join(", ", epochs.Select(x => x.AsString())),
masterCheckpoint, masterCheckpoint,
string.Join(", ", _epochManager.GetLastEpochs(int.MaxValue).Select(x => x.AsString())));
return(0);
}
// if afterCommonEpoch is present, logPosition > afterCommonEpoch.EpochPosition,
// so safe position is definitely the start of afterCommonEpoch
var replicaPosition = afterCommonEpoch == null ? logPosition : afterCommonEpoch.EpochPosition;
if (commonEpoch.EpochNumber == _epochManager.LastEpochNumber)
{
return(Math.Min(replicaPosition, masterCheckpoint));
}
var nextEpoch = _epochManager.GetEpoch(commonEpoch.EpochNumber + 1, throwIfNotFound: false);
if (nextEpoch == null)
{
nextEpoch = _epochManager.GetEpochWithAllEpochs(commonEpoch.EpochNumber + 1, throwIfNotFound: false);
}
if (nextEpoch == null)
{
var msg = string.Format("Replica [{0},S:{1},{2}(0x{3:X}),epochs:\n{4}]\n provided epochs which are not in "
+ "EpochManager (possibly too old, known epochs:\n{5}).\nMaster LogPosition: {6} (0x{7:X}). "
+ "We do not support this case as of now.\n"
+ "CommonEpoch: {8}, AfterCommonEpoch: {9}",
replicaEndPoint, subscriptionId, logPosition, logPosition,
string.Join("\n", epochs.Select(x => x.AsString())),
string.Join("\n", _epochManager.GetLastEpochs(int.MaxValue).Select(x => x.AsString())), masterCheckpoint, masterCheckpoint,
commonEpoch.AsString(), afterCommonEpoch == null ? "<none>" : afterCommonEpoch.AsString());
Log.Error(
"Replica [{replicaEndPoint},S:{subscriptionId},{logPosition}(0x{logPosition:X}),epochs:\n{epochs}]\n provided epochs which are not in "
+ "EpochManager (possibly too old, known epochs:\n{lastEpochs}).\nMaster LogPosition: {masterCheckpoint} (0x{masterCheckpoint:X}). "
+ "We do not support this case as of now.\n"
+ "CommonEpoch: {commonEpoch}, AfterCommonEpoch: {afterCommonEpoch}",
replicaEndPoint,
subscriptionId,
logPosition,
logPosition,
string.Join("\n", epochs.Select(x => x.AsString())),
string.Join("\n", _epochManager.GetLastEpochs(int.MaxValue).Select(x => x.AsString())),
masterCheckpoint,
masterCheckpoint,
commonEpoch.AsString(),
afterCommonEpoch == null ? "<none>" : afterCommonEpoch.AsString()
);
throw new Exception(msg);
}
return(Math.Min(replicaPosition, nextEpoch.EpochPosition));
}