private void LoadAllTransactions()
{
_transactionLog.Seek(0, SeekOrigin.Begin);
var reader = new BinaryReader(_transactionLog);
_lastOffset = reader.ReadInt64();
try
{
while (true)
{
var transaction = ReadTransaction(reader);
if (!transaction.EndMarkerOk)
{
throw new FormatException(
"Inconsistent transaction log. End marker not found at the end of a transaction");
}
if (transaction.TransactionStatus != TransactionStatus.Processed &&
transaction.TransactionStatus != TransactionStatus.Canceled)
{
_transactionQueue.Enqueue(transaction);
}
}
}
catch (EndOfStreamException)
{
// ignore (end of log)
}
if (_transactionQueue.Count > 0)
{
// only the last transaction may be in "Processing" status. In this case there was a failure during transaction processing
// we mark it "ToProcess". Transactions are idempotent
var lastTransaction = _transactionQueue.Peek();
if (lastTransaction.TransactionStatus == TransactionStatus.Processing)
{
ServerLog.LogWarning("Reprocessing incomplete transaction");
lastTransaction.TransactionStatus = TransactionStatus.ToProcess;
UpdateTransactionStatus(lastTransaction);
}
_queueNotEmpty.Set();
}
}
private void LoadAllTransactions()
{
_transactionLog.Seek(0, SeekOrigin.Begin);
var reader = new BinaryReader(_transactionLog);
_lastOffset = reader.ReadInt64();
var completeTransaction = true;
try
{
while (true)
{
var status = reader.ReadInt32();
completeTransaction = false;
var timestamp = reader.ReadInt64();
var length = reader.ReadInt32();
var data = reader.ReadBytes(length);
var offset = reader.ReadInt64();
var id = reader.ReadInt64();
var delay = reader.ReadInt32();
var endMarker = reader.ReadInt64();
if (endMarker != EndMarker)
{
throw new FormatException(
"Inconsistent transaction log. End marker not found at the end of a transaction");
}
completeTransaction = true;
var time = new DateTime(timestamp);
var transaction = new TransactionData
{
TransactionStatus = (TransactionStaus)status,
TimeStamp = time,
Data = data,
Offset = offset,
Id = id,
DelayInMilliseconds = delay
};
if (transaction.TransactionStatus != TransactionStaus.Processed &&
transaction.TransactionStatus != TransactionStaus.Canceled)
{
_transactionQueue.Enqueue(transaction);
}
}
}
catch (EndOfStreamException)
{
if (!completeTransaction)
{
throw new FormatException(
"Inconsistent transaction log. End of file reached in the middle of a transaction");
}
}
if (_transactionQueue.Count > 0)
{
// only the last transaction may be in "Processing" status. In this case there was a failure during transaction processing
// we mark it "ToProcess". Transactions are idempotent
var lastTransaction = _transactionQueue.Peek();
if (lastTransaction.TransactionStatus == TransactionStaus.Processing)
{
ServerLog.LogWarning("Reprocessing incomplete transaction");
lastTransaction.TransactionStatus = TransactionStaus.ToProcess;
UpdateTransactionStatus(lastTransaction);
}
_queueNotEmpty.Set();
}
}
public void ProcessTransactionRequest(TransactionRequest transactionRequest, IClient client,
SafeDictionary <string, DataStore> dataStores)
{
if (transactionRequest.TransactionId == default)
{
client.SendResponse(new ExceptionResponse(
new CacheException(
"Transaction request received without transaction id")));
return;
}
// First try to acquire a write lock on all concerned data stores
var types = transactionRequest.AllCollections;
var keys = dataStores.Keys;
if (types.Any(t => !keys.Contains(t)))
{
throw new NotSupportedException("Type not registered");
}
var transactionId = transactionRequest.TransactionId;
// do not work too hard if it's single stage
if (transactionRequest.IsSingleStage)
{
ProcessSingleStageTransactionRequest(transactionRequest, client, dataStores);
return;
}
var lockAcquired = _lockManager.TryAcquireWriteLock(transactionId, Constants.DelayForLockInMilliseconds, types.ToArray());
if (lockAcquired)
{
var answer = client.ShouldContinue();
if (answer.HasValue && answer.Value)
{
}
else
{
_lockManager.CloseSession(transactionId);
return;
}
}
else
{
client.SendResponse(new ExceptionResponse(
new CacheException(
$"can not acquire write lock on server for transaction {transactionRequest.TransactionId}"),
ExceptionType.FailedToAcquireLock));
return;
}
Dbg.Trace($"S: lock acquired by all clients for transaction {transactionRequest.TransactionId}");
// Second register a durable delayed transaction. It can be cancelled later
try
{
CheckConditions(transactionRequest, dataStores);
// if we reach here the condition check has passed
SaveDurableTransaction(transactionRequest, dataStores);
client.SendResponse(new ReadyResponse());
Dbg.Trace($"S: end writing delayed transaction {transactionRequest.TransactionId}");
}
catch (CacheException e)
{
Dbg.Trace($"error in first stage:{e.Message} ");
client.SendResponse(new ExceptionResponse(e, e.ExceptionType));
// failed to write a durable transaction so stop here
// unlock
_lockManager.CloseSession(transactionRequest.TransactionId);
return;
}
catch (Exception e)
{
Dbg.Trace($"error in first stage:{e.Message} ");
client.SendResponse(new ExceptionResponse(e));
// failed to write a durable transaction so stop here
// unlock
_lockManager.CloseSession(transactionRequest.TransactionId);
return;
}
try
{
Dbg.Trace($"S: begin waiting for client go {transactionRequest.TransactionId}");
var answer = client.ShouldContinue();
Dbg.Trace($"S: end waiting for client go answer = {answer}");
if (answer.HasValue) // the client has answered
{
if (answer.Value)
{
// update the data in memory
ExecuteInMemory(transactionRequest, dataStores);
ServerLog.LogInfo(
$"S: two stage transaction committed successfully {transactionRequest.TransactionId}");
}
else
{
ServerLog.LogWarning(
$"S: two stage transaction cancelled by client on server {transactionRequest.TransactionId}");
// cancel the delayed transaction
_transactionLog?.CancelDelayedTransaction();
}
}
else // the client failed to answer in a reasonable delay (which is less than the delay to commit a delayed transaction )
{
_transactionLog?.CancelDelayedTransaction();
}
}
catch (Exception e)
{
ServerLog.LogInfo($"error in the second stage of a transaction:{e.Message}");
}
// unlock
_lockManager.CloseSession(transactionRequest.TransactionId);
}
