/// <summary>
// Call from WC in response to a client's abort
/// </summary>
/// <param name="context"></param>
public void Abort(TP.Transaction context)
{
// Get the list of names of the resource manager involved in this transaction
List <string> rmNameList = GetRMListForTransaction(context);
if (null == rmNameList)
{
System.Console.WriteLine(string.Format("Transaction {0} unknown", context.Id));
}
// Get the list of resource managers involved in this transaction
List <RM> rmList = new List <RM>();
lock (this.resourceManagers)
{
foreach (string name in rmNameList)
{
RM manager = GetResourceMananger(name);
if (null == manager)
{
continue;
}
rmList.Add(manager);
}
// Write transaction id and list of RM to outstanding transaction list before aborting the transaction
// Flush the entry to the outstanding transaction file immediately
OutstandingTransactions.OutstandingTransactionsValue abortedTransactionValue = new OutstandingTransactions.OutstandingTransactionsValue(
OutstandingTransactions.OutstandingTransactionsValue.TransactionType.Abort,
rmNameList);
lock (OutstandingTransactions)
{
OutstandingTransactions.UpdateAndFlush(context.Id.ToString(), abortedTransactionValue);
System.Console.WriteLine(string.Format("Transaction {0} aborting...", context.Id));
for (int i = 0; i < rmList.Count; ++i)
{
ExecuteActionWithTimeout exec = new ExecuteActionWithTimeout(rmList[i].GetName(), () => rmList[i].Abort(context));
try
{
exec.Run();
}
catch (TimeoutException)
{
System.Console.WriteLine(string.Format("Transaction {0} timed out while waiting for RM {1} to abort...", context.Id, rmList[i].GetName()));
}
}
// PRESUMED ABORT: Once the TM sends out the abort, it forgets about the transaction immediately.
// So we write transaction id and an _empty_ list of unacknowledged RMs to the outstanding transaction list.
// This will cancel out the entry we logged earlier about the transaction and all its RMs.
// Flush the entry to the outstanding transaction file immediately
abortedTransactionValue.nackRMList.Clear();
OutstandingTransactions.UpdateAndFlush(context.Id.ToString(), abortedTransactionValue);
if (abortedTransactionValue.nackRMList.Count == 0)
{
System.Console.WriteLine(string.Format("Transaction {0} aborted", context.Id));
}
else
{
System.Console.WriteLine(string.Format("Transaction {0} aborted with some timeouts", context.Id));
}
}
}
}
// This function reviews all outstanding transaction and reissues Commit() or Abort() to the
// unackowledged RMs
public void recovery()
{
Console.Out.WriteLine("Recovery started...");
List <string> deleteTransactionList = new List <string>(); // Keep track of transactions that are fully acknowledged by all its RMs
lock (OutstandingTransactions)
{
if (OutstandingTransactions.transactionList.Keys.Count == 0)
{
Console.WriteLine("Recovery: No outstanding transactions to recover. Recovery completed.");
return;
}
foreach (string transactionId in OutstandingTransactions.transactionList.Keys)
{
// For each outstanding transaction, get its transaction id and its OutstandingTransactions value
OutstandingTransactions.OutstandingTransactionsValue entry = OutstandingTransactions.transactionList[transactionId];
Transaction context = new Transaction();
context.Id = new Guid(transactionId);
Console.Out.WriteLine(string.Format("Recovery: Recovering transaction {0}...", transactionId));
// For each of the remaining NACK RMs, reissue the Commit or Abort
for (int i = 0; i < entry.nackRMList.Count; ++i)
{
string rmName = entry.nackRMList[i];
RM rm = GetResourceMananger(rmName);
if (rm == null)
{
Console.Out.WriteLine(string.Format("Recovery: Failed to find resource manager {0}", rmName));
}
else
{
ExecuteActionWithTimeout exec;
if (entry.transactionType == OutstandingTransactions.OutstandingTransactionsValue.TransactionType.Commit)
{
Console.Out.WriteLine(string.Format("Recovery: Re-committing resource manager {0}...", rmName));
exec = new ExecuteActionWithTimeout(rmName, () => rm.Commit(context));
}
else
{
Console.Out.WriteLine(string.Format("Recovery: Re-aborting resource manager {0}...", rmName));
exec = new ExecuteActionWithTimeout(rmName, () => rm.Abort(context));
}
// Execute the commit or abort
try
{
exec.Run();
Console.Out.WriteLine("Recovery: Successful!");
// Remove RM from the current transaction since we received the Done message (ie the call didn't time out)
OutstandingTransactions.transactionList[transactionId].nackRMList.RemoveAt(i);
--i;
}
catch (TimeoutException)
{
System.Console.WriteLine("Recovery: Failed!");
}
}
}
// PRESUMED ABORT: If the transaction is Abort, we don't care about the Done message and we forget about
// the transaction immediately.
// For commit transactions, mark transaction for removal if we received Done from all RMs
if (entry.transactionType == OutstandingTransactions.OutstandingTransactionsValue.TransactionType.Abort ||
entry.nackRMList.Count == 0)
{
deleteTransactionList.Add(transactionId);
}
}
// Delete transaction marked for removal from the outstanding transaction list
foreach (string s in deleteTransactionList)
{
OutstandingTransactions.transactionList.Remove(s);
}
// Update file to reflect outstanding transactions status
// This is a full rewrite of the outstanding transaction file and hence it will implicitly garbage collect
// the transactions that are no longer outstanding.
OutstandingTransactions.WriteToFile();
}
Console.Out.WriteLine("Recovery completed.");
}
/// <summary>
// Call from WC in response to a client's commit.
/// </summary>
/// <param name="context"></param>
public void Commit(TP.Transaction context)
{
// Get the list of names of the resource manager involved in this transaction
List <string> rmNameList = GetRMListForTransaction(context);
if (null == rmNameList)
{
System.Console.WriteLine(string.Format("Transaction {0} unknown", context.Id));
throw new AbortTransationException();
}
// Get the list of resource managers involved in this transaction
List <RM> rmList = new List <RM>();
lock (this.resourceManagers)
{
foreach (string name in rmNameList)
{
RM manager = GetResourceMananger(name);
if (null == manager)
{
continue;
}
rmList.Add(manager);
}
// Request to prepare for all resource managers involved in this transaction
bool allPrepared = true;
List <ExecuteFuncWithTimeout <bool> > execPrepareList = new List <ExecuteFuncWithTimeout <bool> >();
try
{
// Execute the Prepare() function for each associated RMs with timeout
for (int i = 0; i < rmList.Count; ++i)
{
ExecuteFuncWithTimeout <bool> exec = new ExecuteFuncWithTimeout <bool>(rmList[i].GetName(), () => rmList[i].Prepare(context));
execPrepareList.Add(exec);
exec.Run();
}
}
// If a timeout occurs, it means that RMs are not all prepared and we should abort
// the transaction
catch (TimeoutException)
{
System.Console.WriteLine(string.Format("Transaction {0} timed out while waiting for RequestToPrepare. Aborting transaction...", context.Id));
allPrepared = false;
}
if (allPrepared)
{
// If all resource managers are ready responded to the request to prepare, check if
// any of them responded NO to the request.
foreach (ExecuteFuncWithTimeout <bool> exec in execPrepareList)
{
if (exec.completed && exec.result == false)
{
allPrepared = false;
System.Console.WriteLine(string.Format("Transaction {0} received No for RequestToPrepare. Aborting transaction...", context.Id));
break;
}
}
}
execPrepareList.Clear();
// Initialize the list of RM to outstanding transaction list in case of recovery
OutstandingTransactions.OutstandingTransactionsValue committedTransactionValue = new OutstandingTransactions.OutstandingTransactionsValue(
OutstandingTransactions.OutstandingTransactionsValue.TransactionType.Commit,
rmNameList);
lock (OutstandingTransactions)
{
// If all resource managers responded Prepared to the Request to prepare, commit the transaction.
if (allPrepared)
{
// Write transaction id and list of RM to outstanding transaction list before committing the transaction
// Flush the entry to the outstanding transaction file immediately
OutstandingTransactions.UpdateAndFlush(context.Id.ToString(), committedTransactionValue);
System.Console.WriteLine(string.Format("Transaction {0} received Prepared from all resource managers. Committing transaction...", context.Id));
// Execute commit() in all associated RMs
for (int i = 0; i < rmList.Count; ++i)
{
ExecuteActionWithTimeout exec = new ExecuteActionWithTimeout(rmList[i].GetName(), () => rmList[i].Commit(context));
try
{
exec.Run();
// Remove RM from list of RM when we received Done (ie no timeout has occurred)
committedTransactionValue.nackRMList.Remove(rmList[i].GetName());
}
catch (TimeoutException)
{
System.Console.WriteLine(string.Format("Transaction {0} timed out while waiting for RM {1} to commit...", context.Id, rmList[i].GetName()));
}
}
// Write transaction id and list of unacknowledged RMs to the outstanding transaction list.
// Flush the entry to the outstanding transaction file immediately
OutstandingTransactions.UpdateAndFlush(context.Id.ToString(), committedTransactionValue);
if (committedTransactionValue.nackRMList.Count == 0)
{
System.Console.WriteLine(string.Format("Transaction {0} commited", context.Id));
}
else
{
System.Console.WriteLine(string.Format("Transaction {0} commited with some timeouts", context.Id));
}
}
else
{
// Initialize the list of RM to outstanding transaction list in case of recovery
// Write transaction id and list of RM to outstanding transaction list before aborting the transaction
// Flush the entry to the outstanding transaction file immediately
committedTransactionValue.transactionType = OutstandingTransactions.OutstandingTransactionsValue.TransactionType.Abort;
OutstandingTransactions.UpdateAndFlush(context.Id.ToString(), committedTransactionValue);
System.Console.WriteLine(string.Format("Transaction {0} aborting...", context.Id));
// Execute abort() in all associated RMs
for (int i = 0; i < rmList.Count; ++i)
{
ExecuteActionWithTimeout exec = new ExecuteActionWithTimeout(rmList[i].GetName(), () => rmList[i].Abort(context));
try
{
exec.Run();
}
catch (TimeoutException)
{
System.Console.WriteLine(string.Format("Transaction {0} timed out while waiting for RM {1} to abort...", context.Id, rmList[i].GetName()));
}
}
// PRESUMED ABORT: Once the TM sends out the abort, it forgets about the transaction immediately.
// So we write transaction id and an _empty_ list of unacknowledged RMs to the outstanding transaction list.
// This will cancel out the entry we logged earlier about the transaction and all its RMs.
// Flush the entry to the outstanding transaction file immediately
committedTransactionValue.nackRMList.Clear();
OutstandingTransactions.UpdateAndFlush(context.Id.ToString(), committedTransactionValue);
if (committedTransactionValue.nackRMList.Count == 0)
{
System.Console.WriteLine(string.Format("Transaction {0} aborted", context.Id));
}
else
{
System.Console.WriteLine(string.Format("Transaction {0} aborted with some timeouts", context.Id));
}
}
}
}
}
