private void Rollback()
{
var list = this.ResouceManagers.ResourceManagers;
for (int i = 0; i < list.Count; i++)
{
RM r = list[i];
string outstring = string.Format("2PC:Rollback {0}:{1}\r", this.Context.Id, this.ResouceManagers.RMNames[i]);
this.Message += outstring;
Console.Write(outstring);
int temp = i;
ThreadPool.QueueUserWorkItem(o =>
{
while (true)
{
try
{
r.Abort(this.Context);
break;
}
catch (WebException)
{
}
Console.WriteLine("ResourceManager {0} is not ready, wait 0.5 second", this.ResouceManagers.RMNames[temp]);
Thread.Sleep(500);
}
// presume abort, if we don't check return of the abort
// Once the abort message is sent, it is consider done.
this.SetState(temp, CommitState.Rollbacked);
});
}
}
// 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.");
}
