private async Task DoLoad()
{
this.logger.Debug("DoLoad");
// load inital state
TransactionalStorageLoadResponse <TState> loadResponse = await this.storage.Load(StateName);
this.eTag = loadResponse.ETag;
this.metadata = Metadata.FromString(loadResponse.Metadata);
this.version = this.metadata.HighestVersion;
this.highestReadTransactionId = this.metadata.HighestReadTransactionId;
this.commitedState = loadResponse.CommittedState;
foreach (PendingTransactionState <TState> pendingState in loadResponse.PendingStates)
{
if (this.logger.IsEnabled(LogLevel.Debug))
{
this.logger.Debug("Rebuilding log from storage for {0}", pendingState.SequenceId);
}
this.log[pendingState.SequenceId] = new LogRecord <TState>
{
NewVal = pendingState.State,
Version = (TransactionalResourceVersion.TryParse(pendingState.TransactionId, out TransactionalResourceVersion version)) ? version : default(TransactionalResourceVersion)
};
}
UpdateActiveState();
}
/// <summary>
/// Find the appropriate version of the state to serve for this transaction.
/// We enforce reads in transaction id order, hence we find the version written by the highest
/// transaction less than or equal to this one
/// </summary>
private bool TryGetVersion(long transactionId, out TState readState, out TransactionalResourceVersion readVersion)
{
readState = this.value;
readVersion = this.version;
bool versionAvailable = this.version.TransactionId <= transactionId;
LogRecord <TState> logRecord = null;
foreach (KeyValuePair <long, LogRecord <TState> > kvp in this.log)
{
if (kvp.Key > transactionId)
{
break;
}
logRecord = kvp.Value;
}
if (logRecord == null)
{
return(versionAvailable);
}
readState = logRecord.NewVal;
readVersion = logRecord.Version;
return(true);
}
/// <summary>
/// Undo writes to restore state to pre transaction value.
/// </summary>
private void Rollback(long transactionId)
{
List <KeyValuePair <long, LogRecord <TState> > > records = this.log.SkipWhile(kvp => kvp.Key < transactionId).ToList();
foreach (KeyValuePair <long, LogRecord <TState> > kvp in records)
{
if (this.logger.IsEnabled(LogLevel.Debug))
{
this.logger.Debug("Removing transaction {0} in rollback", kvp.Key);
}
this.log.Remove(kvp.Key);
this.transactionCopy.Remove(kvp.Key);
}
if (this.log.Count > 0)
{
LogRecord <TState> lastLogRecord = this.log.Values.Last();
if (this.logger.IsEnabled(LogLevel.Debug) && this.version != lastLogRecord.Version)
{
this.logger.Debug("Rolling back from {0} to {1}", this.version, lastLogRecord.Version);
}
this.version = lastLogRecord.Version;
this.value = lastLogRecord.NewVal;
}
else
{
if (this.logger.IsEnabled(LogLevel.Debug) && this.version != this.metadata.StableVersion)
{
this.logger.Debug("Rolling back to stable version, from {0} to {1}", this.version, this.metadata.StableVersion);
}
this.version = this.metadata.StableVersion;
this.value = this.commitedState;
}
}
public void RecordRead(ITransactionalResource transactionalResource, TransactionalResourceVersion readVersion, long stableVersion)
{
if (readVersion.TransactionId == TransactionId)
{
// Just reading our own write here.
// Sanity check to see if there's a lost write.
int resourceWriteNumber;
if (WriteSet.TryGetValue(transactionalResource, out resourceWriteNumber) &&
resourceWriteNumber > readVersion.WriteNumber)
{
// Context has record of more writes than we have, some writes must be lost.
throw new OrleansTransactionAbortedException(TransactionId, "Lost Write");
}
}
else
{
TransactionalResourceVersion resourceReadVersion;
if (ReadSet.TryGetValue(transactionalResource, out resourceReadVersion) &&
resourceReadVersion != readVersion)
{
// Uh-oh. Read two different versions of the grain.
throw new OrleansValidationFailedException(TransactionId);
}
ReadSet[transactionalResource] = readVersion;
if (readVersion.TransactionId != TransactionId &&
readVersion.TransactionId > stableVersion)
{
DependentTransactions.Add(readVersion.TransactionId);
}
}
}
/// <summary>
/// Transactional Write procedure.
/// </summary>
public void Save()
{
var info = TransactionContext.GetTransactionInfo();
if (this.logger.IsEnabled(LogLevel.Debug))
{
this.logger.Debug("Write {0}", info);
}
if (info.IsReadOnly)
{
// For obvious reasons...
throw new OrleansReadOnlyViolatedException(info.TransactionId);
}
Rollback();
var copiedValue = this.transactionCopy[info.TransactionId];
//
// Validation
//
if (this.version.TransactionId > info.TransactionId || this.highestReadTransactionId >= info.TransactionId)
{
// Prevent cycles. Wait-die
throw new OrleansTransactionWaitDieException(info.TransactionId);
}
TransactionalResourceVersion nextVersion = TransactionalResourceVersion.Create(info.TransactionId,
this.version.TransactionId == info.TransactionId ? this.version.WriteNumber + 1 : 1);
//
// Update Transaction Context
//
info.RecordWrite(transactionalResource, this.version, this.metadata.StableVersion.TransactionId);
//
// Modify the State
//
if (!this.log.ContainsKey(info.TransactionId))
{
LogRecord <TState> r = new LogRecord <TState>();
this.log[info.TransactionId] = r;
}
LogRecord <TState> logRecord = this.log[info.TransactionId];
logRecord.NewVal = copiedValue;
logRecord.Version = nextVersion;
this.value = copiedValue;
this.version = nextVersion;
this.transactionCopy.Remove(info.TransactionId);
}
private async Task <bool> PersistCommit(long transactionId)
{
transactionId = Math.Max(this.highCommitTransactionId, transactionId);
if (transactionId <= this.metadata.StableVersion.TransactionId)
{
// Transaction commit already persisted.
return(true);
}
// find version related to this transaction
LogRecord <TState> stableRecord = this.log.First(kvp => kvp.Key <= transactionId).Value;
TransactionalResourceVersion stableversion = stableRecord.Version;
TState stableState = stableRecord.NewVal;
// Trim the logs to remove old versions.
// Note that we try to keep the highest version that is below or equal to the ReadOnlyTransactionId
// so that we can use it to serve read only transactions.
long highestKey = transactionId;
foreach (var key in this.log.Keys)
{
if (key > this.transactionAgent.ReadOnlyTransactionId)
{
break;
}
highestKey = key;
}
if (this.log.Count != 0)
{
List <KeyValuePair <long, LogRecord <TState> > > records = this.log.TakeWhile(kvp => kvp.Key < highestKey).ToList();
if (this.logger.IsEnabled(LogLevel.Debug))
{
records.ForEach(kvp => this.logger.Debug("Removing committed transaction from log: transactionId: {1}", kvp.Key));
}
records.ForEach(kvp => this.log.Remove(kvp.Key));
}
Metadata newMetadata = new Metadata()
{
StableVersion = stableversion,
HighestVersion = this.version,
HighestReadTransactionId = this.highestReadTransactionId,
};
this.eTag = await this.storage.Confirm(StateName, this.eTag, newMetadata.ToString(), stableversion.ToString());
this.metadata = newMetadata;
this.commitedState = stableState;
UpdateActiveState();
return(true);
}
public async Task Commit(ITransactionInfo info)
{
var transactionInfo = (TransactionInfo)info;
TransactionsStatisticsGroup.OnTransactionCommitRequest();
if (transactionInfo.IsReadOnly)
{
return;
}
var completion = new TaskCompletionSource <bool>();
bool canCommit = true;
List <Task <bool> > prepareTasks = new List <Task <bool> >(transactionInfo.WriteSet.Count);
foreach (var g in transactionInfo.WriteSet.Keys)
{
TransactionalResourceVersion write = TransactionalResourceVersion.Create(transactionInfo.TransactionId, transactionInfo.WriteSet[g]);
TransactionalResourceVersion?read = null;
if (transactionInfo.ReadSet.ContainsKey(g))
{
read = transactionInfo.ReadSet[g];
transactionInfo.ReadSet.Remove(g);
}
prepareTasks.Add(g.Prepare(transactionInfo.TransactionId, write, read));
}
foreach (var g in transactionInfo.ReadSet.Keys)
{
TransactionalResourceVersion read = transactionInfo.ReadSet[g];
prepareTasks.Add(g.Prepare(transactionInfo.TransactionId, null, read));
}
await Task.WhenAll(prepareTasks);
foreach (var t in prepareTasks)
{
if (!t.Result)
{
canCommit = false;
}
}
if (!canCommit)
{
TransactionsStatisticsGroup.OnTransactionAborted();
abortedTransactions.TryAdd(transactionInfo.TransactionId, 0);
throw new OrleansPrepareFailedException(transactionInfo.TransactionId);
}
commitCompletions.TryAdd(transactionInfo.TransactionId, completion);
transactionCommitQueue.Enqueue(transactionInfo);
await completion.Task;
}
/// <summary>
/// Read Log from persistent state interface.
/// </summary>
private void RevertToPersistedLog()
{
this.log.Clear();
foreach (KeyValuePair <long, TState> kvp in this.storage.State.Logs)
{
this.log[kvp.Key] = new LogRecord <TState>
{
NewVal = kvp.Value,
Version = TransactionalResourceVersion.Create(kvp.Key, 1)
};
}
}
public void RecordWrite(ITransactionalResource transactionalResource, TransactionalResourceVersion latestVersion, long stableVersion)
{
int writeNumber;
WriteSet.TryGetValue(transactionalResource, out writeNumber);
WriteSet[transactionalResource] = writeNumber + 1;
if (latestVersion.TransactionId != TransactionId && latestVersion.TransactionId > stableVersion)
{
DependentTransactions.Add(latestVersion.TransactionId);
}
}
private void DoRecovery()
{
TransactionalStateRecord <TState> storageState = this.storage.State;
this.stableVersion = storageState.StableVersion;
this.writeLowerBound = storageState.WriteLowerBound;
this.version = storageState.Version;
this.value = storageState.Value;
RevertToPersistedLog();
// Rollback any known aborted transactions
Restore();
}
private void UpdateActiveState()
{
this.logger.Debug("UpdateActiveState");
if (this.metadata.HighestVersion > this.version)
{
this.version = this.metadata.HighestVersion;
}
this.value = this.log.TryGetValue(this.version.TransactionId, out LogRecord <TState> record)
? record.NewVal
: this.commitedState;
this.log.Clear();
// Rollback any known aborted transactions
Rollback();
}
private async Task <bool> PersistCommit(long transactionId)
{
transactionId = Math.Max(this.highCommitTransactionId, transactionId);
if (transactionId <= this.metadata.StableVersion.TransactionId)
{
// Transaction commit already persisted.
return(true);
}
// find version related to this transaction
TransactionalResourceVersion stableversion = this.log.First(kvp => kvp.Key <= transactionId).Value.Version;
// Trim the logs to remove old versions.
// Note that we try to keep the highest version that is below or equal to the ReadOnlyTransactionId
// so that we can use it to serve read only transactions.
long highestKey = transactionId;
foreach (var key in this.log.Keys)
{
if (key > this.transactionAgent.ReadOnlyTransactionId)
{
break;
}
highestKey = key;
}
if (this.log.Count != 0)
{
List <KeyValuePair <long, LogRecord <TState> > > records = this.log.TakeWhile(kvp => kvp.Key < highestKey).ToList();
records.ForEach(kvp => this.log.Remove(kvp.Key));
}
this.metadata.StableVersion = stableversion;
this.metadata.HighestVersion = this.version;
this.metadata.HighestReadTransactionId = this.highestReadTransactionId;
this.eTag = await this.storage.Confirm(StateName, this.eTag, this.metadata.ToString(), stableversion.ToString());
return(true);
}
/// <summary>
/// Undo writes to restore state to pre transaction value.
/// </summary>
private void Rollback(long transactionId)
{
List <KeyValuePair <long, LogRecord <TState> > > records = this.log.SkipWhile(kvp => kvp.Key < transactionId).ToList();
foreach (KeyValuePair <long, LogRecord <TState> > kvp in records)
{
this.log.Remove(kvp.Key);
this.transactionCopy.Remove(kvp.Key);
}
if (this.log.Count > 0)
{
LogRecord <TState> lastLogRecord = this.log.Values.Last();
this.version = lastLogRecord.Version;
this.value = lastLogRecord.NewVal;
}
else
{
this.version = TransactionalResourceVersion.Create(0, 0);
this.value = new TState();
}
}
private async Task DoRecovery()
{
// load inital state
TransactionalStorageLoadResponse <TState> loadResponse = await this.storage.Load(StateName);
this.eTag = loadResponse.ETag;
this.metadata = Metadata.FromString(loadResponse.Metadata);
this.highestReadTransactionId = this.metadata.HighestReadTransactionId;
this.version = this.metadata.HighestVersion;
this.value = loadResponse.CommittedState;
this.log.Clear();
foreach (PendingTransactionState <TState> pendingState in loadResponse.PendingStates)
{
this.log[pendingState.SequenceId] = new LogRecord <TState>
{
NewVal = pendingState.State,
Version = (TransactionalResourceVersion.TryParse(pendingState.TransactionId, out TransactionalResourceVersion version)) ? version : default(TransactionalResourceVersion)
};
}
// Rollback any known aborted transactions
Restore();
}
