override protected void CleanupTransactionOnCompletion(SysTx.Transaction transaction)
{
// Note: unlocked, potentially multi-threaded code, so pull delegate to local to
// ensure it doesn't change between test and call.
SqlDelegatedTransaction delegatedTransaction = DelegatedTransaction;
if (null != delegatedTransaction)
{
delegatedTransaction.TransactionEnded(transaction);
}
}
private void TransactionEndedByServer(long transactionId, TransactionState transactionState)
{
// Some extra steps required when the server initiates the ending of a transaction unilaterally
// as opposed to the client initiating it.
// Basically, we have to make the delegated transaction (if there is one) aware of the situation.
SqlDelegatedTransaction delegatedTransaction = DelegatedTransaction;
if (null != delegatedTransaction)
{
delegatedTransaction.Transaction.Rollback(); // just to make sure...
DelegatedTransaction = null; // He's dead, Jim.
}
// Now handle the standard transaction-ended stuff.
TransactionEnded(transactionId, transactionState);
}
private void EnlistNonNull(SysTx.Transaction tx)
{
Debug.Assert(null != tx, "null transaction?");
SqlClientEventSource.Log.TryAdvancedTraceEvent("<sc.SqlInternalConnection.EnlistNonNull|ADV> {0}, transaction {1}.", ObjectID, tx.GetHashCode());
bool hasDelegatedTransaction = false;
if (Is2005OrNewer)
{
SqlClientEventSource.Log.TryAdvancedTraceEvent("<sc.SqlInternalConnection.EnlistNonNull|ADV> {0}, attempting to delegate", ObjectID);
// Promotable transactions are only supported on 2005
// servers or newer.
SqlDelegatedTransaction delegatedTransaction = new SqlDelegatedTransaction(this, tx);
try
{
// NOTE: System.Transactions claims to resolve all
// potential race conditions between multiple delegate
// requests of the same transaction to different
// connections in their code, such that only one
// attempt to delegate will succeed.
// NOTE: PromotableSinglePhaseEnlist will eventually
// make a round trip to the server; doing this inside
// a lock is not the best choice. We presume that you
// aren't trying to enlist concurrently on two threads
// and leave it at that -- We don't claim any thread
// safety with regard to multiple concurrent requests
// to enlist the same connection in different
// transactions, which is good, because we don't have
// it anyway.
// PromotableSinglePhaseEnlist may not actually promote
// the transaction when it is already delegated (this is
// the way they resolve the race condition when two
// threads attempt to delegate the same Lightweight
// Transaction) In that case, we can safely ignore
// our delegated transaction, and proceed to enlist
// in the promoted one.
// NOTE: Global Transactions is an Azure SQL DB only
// feature where the Transaction Manager (TM) is not
// MS-DTC. Sys.Tx added APIs to support Non MS-DTC
// promoter types/TM in .NET 4.6.1. Following directions
// from .NETFX shiproom, to avoid a "hard-dependency"
// (compile time) on Sys.Tx, we use reflection to invoke
// the new APIs. Further, the _isGlobalTransaction flag
// indicates that this is an Azure SQL DB Transaction
// that could be promoted to a Global Transaction (it's
// always false for on-prem Sql Server). The Promote()
// call in SqlDelegatedTransaction makes sure that the
// right Sys.Tx.dll is loaded and that Global Transactions
// are actually allowed for this Azure SQL DB.
if (_isGlobalTransaction)
{
if (SysTxForGlobalTransactions.EnlistPromotableSinglePhase == null)
{
// This could be a local Azure SQL DB transaction.
hasDelegatedTransaction = tx.EnlistPromotableSinglePhase(delegatedTransaction);
}
else
{
hasDelegatedTransaction = (bool)SysTxForGlobalTransactions.EnlistPromotableSinglePhase.Invoke(tx, new object[] { delegatedTransaction, _globalTransactionTMID });
}
}
else
{
// This is an MS-DTC distributed transaction
hasDelegatedTransaction = tx.EnlistPromotableSinglePhase(delegatedTransaction);
}
if (hasDelegatedTransaction)
{
this.DelegatedTransaction = delegatedTransaction;
SqlClientEventSource.Log.TryAdvancedTraceEvent("<sc.SqlInternalConnection.EnlistNonNull|ADV> {0}, delegated to transaction {1} with transactionId=0x{2}", ObjectID, null != CurrentTransaction ? CurrentTransaction.ObjectID : 0, null != CurrentTransaction ? CurrentTransaction.TransactionId : SqlInternalTransaction.NullTransactionId);
}
}
catch (SqlException e)
{
// we do not want to eat the error if it is a fatal one
if (e.Class >= TdsEnums.FATAL_ERROR_CLASS)
{
throw;
}
// if the parser is null or its state is not openloggedin, the connection is no longer good.
SqlInternalConnectionTds tdsConnection = this as SqlInternalConnectionTds;
if (tdsConnection != null)
{
TdsParser parser = tdsConnection.Parser;
if (parser == null || parser.State != TdsParserState.OpenLoggedIn)
{
throw;
}
}
ADP.TraceExceptionWithoutRethrow(e);
// In this case, SqlDelegatedTransaction.Initialize
// failed and we don't necessarily want to reject
// things -- there may have been a legitimate reason
// for the failure.
}
}
if (!hasDelegatedTransaction)
{
SqlClientEventSource.Log.TryAdvancedTraceEvent("<sc.SqlInternalConnection.EnlistNonNull|ADV> {0}, delegation not possible, enlisting.", ObjectID);
byte[] cookie = null;
if (_isGlobalTransaction)
{
if (SysTxForGlobalTransactions.GetPromotedToken == null)
{
throw SQL.UnsupportedSysTxForGlobalTransactions();
}
cookie = (byte[])SysTxForGlobalTransactions.GetPromotedToken.Invoke(tx, null);
}
else
{
if (null == _whereAbouts)
{
byte[] dtcAddress = GetDTCAddress();
if (null == dtcAddress)
{
throw SQL.CannotGetDTCAddress();
}
_whereAbouts = dtcAddress;
}
cookie = GetTransactionCookie(tx, _whereAbouts);
}
// send cookie to server to finish enlistment
PropagateTransactionCookie(cookie);
_isEnlistedInTransaction = true;
SqlClientEventSource.Log.TryAdvancedTraceEvent("<sc.SqlInternalConnection.EnlistNonNull|ADV> {0}, enlisted with transaction {1} with transactionId=0x{2}", ObjectID, null != CurrentTransaction ? CurrentTransaction.ObjectID : 0, null != CurrentTransaction ? CurrentTransaction.TransactionId : SqlInternalTransaction.NullTransactionId);
}
EnlistedTransaction = tx; // Tell the base class about our enlistment
// If we're on a 2005 or newer server, and we we delegate the
// transaction successfully, we will have done a begin transaction,
// which produces a transaction id that we should execute all requests
// on. The TdsParser or SmiEventSink will store this information as
// the current transaction.
//
// Likewise, propagating a transaction to a 2005 or newer server will
// produce a transaction id that The TdsParser or SmiEventSink will
// store as the current transaction.
//
// In either case, when we're working with a 2005 or newer server
// we better have a current transaction by now.
Debug.Assert(!Is2005OrNewer || null != CurrentTransaction, "delegated/enlisted transaction with null current transaction?");
}
