abstract public void EnlistTransaction(SysTx.Transaction transaction);
// Cleanup connection's transaction-specific structures (currently used by Delegated transaction).
// This is a separate method because cleanup can be triggered in multiple ways for a delegated
// transaction.
virtual protected void CleanupTransactionOnCompletion(SysTx.Transaction transaction) {
}
override public void EnlistTransaction(SysTx.Transaction transaction) { // MDAC 78997
OleDbConnection.VerifyExecutePermission();
OleDbConnection outerConnection = Connection;
if (null != LocalTransaction) {
throw ADP.LocalTransactionPresent();
}
EnlistTransactionInternal(transaction);
}
internal void ActivateConnection(SysTx.Transaction transaction) {
// Internal method called from the connection pooler so we don't expose
// the Activate method publicly.
Bid.PoolerTrace("<prov.DbConnectionInternal.ActivateConnection|RES|INFO|CPOOL> %d#, Activating\n", ObjectID);
#if DEBUG
int activateCount = Interlocked.Increment(ref _activateCount);
Debug.Assert(1 == activateCount, "activated multiple times?");
#endif // DEBUG
Activate(transaction);
PerformanceCounters.NumberOfActiveConnections.Increment();
}
override public void EnlistTransaction(SysTx.Transaction transaction) {
CONNECTIONOBJECTNAME.ExecutePermission.Demand();
Bid.Trace( "<prov.DbConnectionHelper.EnlistTransaction|RES|TRAN> %d#, Connection enlisting in a transaction.\n", ObjectID);
// If we're currently enlisted in a transaction and we were called
// on the EnlistTransaction method (Whidbey) we're not allowed to
// enlist in a different transaction.
DbConnectionInternal innerConnection = InnerConnection;
// NOTE: since transaction enlistment involves round trips to the
// server, we don't want to lock here, we'll handle the race conditions
// elsewhere.
SysTx.Transaction enlistedTransaction = innerConnection.EnlistedTransaction;
if (enlistedTransaction != null) {
// Allow calling enlist if already enlisted (no-op)
if (enlistedTransaction.Equals(transaction)) {
return;
}
// Allow enlisting in a different transaction if the enlisted transaction has completed.
if (enlistedTransaction.TransactionInformation.Status == SysTx.TransactionStatus.Active)
{
throw ADP.TransactionPresent();
}
}
RepairInnerConnection();
InnerConnection.EnlistTransaction(transaction);
// NOTE: If this outer connection were to be GC'd while we're
// enlisting, the pooler would attempt to reclaim the inner connection
// while we're attempting to enlist; not sure how likely that is but
// we should consider a GC.KeepAlive(this) here.
GC.KeepAlive(this);
}
override public void EnlistTransaction(SysTx.Transaction transaction) {
OuterConnection.Open_EnlistTransaction(transaction);
}
static private byte[] GetTransactionCookie(SysTx.Transaction transaction, byte[] whereAbouts) {
byte[] transactionCookie = null;
if (null != transaction) {
transactionCookie = SysTx.TransactionInterop.GetExportCookie(transaction, whereAbouts);
}
return transactionCookie;
}
void TransactionCompletedEvent(object sender, SysTx.TransactionEventArgs e) {
SysTx.Transaction transaction = e.Transaction;
Bid.Trace("<prov.DbConnectionInternal.TransactionCompletedEvent|RES|CPOOL> %d#, Transaction Completed. (pooledCount=%d)\n", ObjectID, _pooledCount);
CleanupTransactionOnCompletion(transaction);
CleanupConnectionOnTransactionCompletion(transaction);
}
private void EnlistNonNull(SysTx.Transaction tx) {
Debug.Assert(null != tx, "null transaction?");
if (Bid.AdvancedOn) {
Bid.Trace("<sc.SqlInternalConnection.EnlistNonNull|ADV> %d#, transaction %d#.\n", base.ObjectID, tx.GetHashCode());
}
bool hasDelegatedTransaction = false;
if (IsYukonOrNewer) {
if (Bid.AdvancedOn) {
Bid.Trace("<sc.SqlInternalConnection.EnlistNonNull|ADV> %d#, attempting to delegate\n", base.ObjectID);
}
// Promotable transactions are only supported on Yukon
// 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.
if (tx.EnlistPromotableSinglePhase(delegatedTransaction)) {
hasDelegatedTransaction = true;
this.DelegatedTransaction = delegatedTransaction;
if (Bid.AdvancedOn) {
long transactionId = SqlInternalTransaction.NullTransactionId;
int transactionObjectID = 0;
if (null != CurrentTransaction) {
transactionId = CurrentTransaction.TransactionId;
transactionObjectID = CurrentTransaction.ObjectID;
}
Bid.Trace("<sc.SqlInternalConnection.EnlistNonNull|ADV> %d#, delegated to transaction %d# with transactionId=0x%I64x\n", base.ObjectID, transactionObjectID, transactionId);
}
}
}
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) {
if (Bid.AdvancedOn) {
Bid.Trace("<sc.SqlInternalConnection.EnlistNonNull|ADV> %d#, delegation not possible, enlisting.\n", base.ObjectID);
}
byte[] cookie = null;
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;
if (Bid.AdvancedOn) {
long transactionId = SqlInternalTransaction.NullTransactionId;
int transactionObjectID = 0;
if (null != CurrentTransaction) {
transactionId = CurrentTransaction.TransactionId;
transactionObjectID = CurrentTransaction.ObjectID;
}
Bid.Trace("<sc.SqlInternalConnection.EnlistNonNull|ADV> %d#, enlisted with transaction %d# with transactionId=0x%I64x\n", base.ObjectID, transactionObjectID, transactionId);
}
}
EnlistedTransaction = tx; // Tell the base class about our enlistment
// If we're on a Yukon 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 Yukon 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 Yukon or newer server
// we better have a current transaction by now.
Debug.Assert(!IsYukonOrNewer || null != CurrentTransaction, "delegated/enlisted transaction with null current transaction?");
}
override public void EnlistTransaction(SysTx.Transaction transaction) {
SqlConnection.VerifyExecutePermission();
ValidateConnectionForExecute(null);
// If a connection has a local transaction outstanding and you try
// to enlist in a DTC transaction, SQL Server will rollback the
// local transaction and then do the enlist (7.0 and 2000). So, if
// the user tries to do this, throw.
if (HasLocalTransaction) {
throw ADP.LocalTransactionPresent();
}
if (null != transaction && transaction.Equals(EnlistedTransaction)) {
// No-op if this is the current transaction
return;
}
// If a connection is already enlisted in a DTC transaction and you
// try to enlist in another one, in 7.0 the existing DTC transaction
// would roll back and then the connection would enlist in the new
// one. In SQL 2000 & Yukon, when you enlist in a DTC transaction
// while the connection is already enlisted in a DTC transaction,
// the connection simply switches enlistments. Regardless, simply
// enlist in the user specified distributed transaction. This
// behavior matches OLEDB and ODBC.
TdsParser bestEffortCleanupTarget = null;
RuntimeHelpers.PrepareConstrainedRegions();
try {
#if DEBUG
TdsParser.ReliabilitySection tdsReliabilitySection = new TdsParser.ReliabilitySection();
RuntimeHelpers.PrepareConstrainedRegions();
try {
tdsReliabilitySection.Start();
#else
{
#endif //DEBUG
bestEffortCleanupTarget = SqlInternalConnection.GetBestEffortCleanupTarget(Connection);
Enlist(transaction);
}
#if DEBUG
finally {
tdsReliabilitySection.Stop();
}
#endif //DEBUG
}
catch (System.OutOfMemoryException e) {
Connection.Abort(e);
throw;
}
catch (System.StackOverflowException e) {
Connection.Abort(e);
throw;
}
catch (System.Threading.ThreadAbortException e) {
Connection.Abort(e);
SqlInternalConnection.BestEffortCleanup(bestEffortCleanupTarget);
throw;
}
}
protected void Enlist(SysTx.Transaction tx) {
// This method should not be called while the connection has a
// reference to an active delegated transaction.
// Manual enlistment via SqlConnection.EnlistTransaction
// should catch this case and throw an exception.
//
// Automatic enlistment isn't possible because
// Sys.Tx keeps the connection alive until the transaction is completed.
Debug.Assert (!IsNonPoolableTransactionRoot, "cannot defect an active delegated transaction!"); // potential race condition, but it's an assert
if (null == tx) {
if (IsEnlistedInTransaction)
{
EnlistNull();
}
else
{
// When IsEnlistedInTransaction is false, it means we are in one of two states:
// 1. EnlistTransaction is null, so the connection is truly not enlisted in a transaction, or
// 2. Connection is enlisted in a SqlDelegatedTransaction.
//
// For #2, we have to consider whether or not the delegated transaction is active.
// If it is not active, we allow the enlistment in the NULL transaction.
//
// If it is active, technically this is an error.
// However, no exception is thrown as this was the precedent (and this case is silently ignored, no error, but no enlistment either).
// There are two mitigations for this:
// 1. SqlConnection.EnlistTransaction checks that the enlisted transaction has completed before allowing a different enlistment.
// 2. For debug builds, the assert at the beginning of this method checks for an enlistment in an active delegated transaction.
SysTx.Transaction enlistedTransaction = EnlistedTransaction;
if (enlistedTransaction != null && enlistedTransaction.TransactionInformation.Status != SysTx.TransactionStatus.Active)
{
EnlistNull();
}
}
}
// Only enlist if it's different...
else if (!tx.Equals(EnlistedTransaction)) { // WebData 20000024 - Must use Equals, not !=
EnlistNonNull(tx);
}
}
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);
}
}
internal void EnlistTransactionInternal(SysTx.Transaction transaction) {
OleDbConnection.VerifyExecutePermission();
SysTx.IDtcTransaction oleTxTransaction = ADP.GetOletxTransaction(transaction);
IntPtr hscp;
Bid.ScopeEnter(out hscp, "<oledb.ITransactionJoin.JoinTransaction|API|OLEDB> %d#\n", ObjectID);
try {
using(ITransactionJoinWrapper transactionJoin = ITransactionJoin()) {
if (null == transactionJoin.Value) {
throw ODB.TransactionsNotSupported(Provider, (Exception)null);
}
transactionJoin.Value.JoinTransaction(oleTxTransaction, (int) IsolationLevel.Unspecified, 0, IntPtr.Zero);
_unEnlistDuringDeactivate = (null != transaction);
}
}
finally {
Bid.ScopeLeave(ref hscp);
}
EnlistedTransaction = transaction;
}
// Detach transaction from connection.
internal void DetachTransaction(SysTx.Transaction transaction, bool isExplicitlyReleasing) {
Bid.Trace("<prov.DbConnectionInternal.DetachTransaction|RES|CPOOL> %d#, Transaction Completed. (pooledCount=%d)\n", ObjectID, _pooledCount);
// potentially a multi-threaded event, so lock the connection to make sure we don't enlist in a new
// transaction between compare and assignment. No need to short circuit outside of lock, since failed comparisons should
// be the exception, not the rule.
lock (this) {
// Detach if detach-on-end behavior, or if outer connection was closed
DbConnection owner = (DbConnection)Owner;
if (isExplicitlyReleasing || UnbindOnTransactionCompletion || null == owner) {
SysTx.Transaction currentEnlistedTransaction = _enlistedTransaction;
if (currentEnlistedTransaction != null && transaction.Equals(currentEnlistedTransaction)) {
EnlistedTransaction = null;
if (IsTxRootWaitingForTxEnd) {
DelegatedTransactionEnded();
}
}
}
}
}
internal void Open_EnlistTransaction(SysTx.Transaction transaction) {
OdbcConnection.VerifyExecutePermission();
if ((null != this.weakTransaction) && this.weakTransaction.IsAlive) {
throw ADP.LocalTransactionPresent();
}
SysTx.IDtcTransaction oleTxTransaction = ADP.GetOletxTransaction(transaction);
OdbcConnectionHandle connectionHandle = ConnectionHandle;
ODBC32.RetCode retcode;
if (null == oleTxTransaction) {
retcode = connectionHandle.SetConnectionAttribute2(ODBC32.SQL_ATTR.SQL_COPT_SS_ENLIST_IN_DTC, (IntPtr) ODBC32.SQL_DTC_DONE, ODBC32.SQL_IS_PTR);
}
else {
retcode = connectionHandle.SetConnectionAttribute4(ODBC32.SQL_ATTR.SQL_COPT_SS_ENLIST_IN_DTC, oleTxTransaction, ODBC32.SQL_IS_PTR);
}
if (retcode != ODBC32.RetCode.SUCCESS) {
HandleError(connectionHandle, retcode);
}
// Tell the base class about our enlistment
((OdbcConnectionOpen)InnerConnection).EnlistedTransaction = transaction;
}
// Handle transaction detach, pool cleanup and other post-transaction cleanup tasks associated with
internal void CleanupConnectionOnTransactionCompletion(SysTx.Transaction transaction) {
DetachTransaction(transaction, false);
DbConnectionPool pool = Pool;
if (null != pool) {
pool.TransactionEnded(transaction, this);
}
}
override protected void Activate(SysTx.Transaction transaction) {
throw ADP.ClosedConnectionError();
}
private void TransactionOutcomeEnlist(SysTx.Transaction transaction) {
transaction.TransactionCompleted += new SysTx.TransactionCompletedEventHandler(TransactionCompletedEvent);
}
override public void EnlistTransaction(SysTx.Transaction transaction) {
throw ADP.ClosedConnectionError();
}
override protected void Activate(SysTx.Transaction transaction) {
OdbcConnection.ExecutePermission.Demand();
}
abstract protected void Activate(SysTx.Transaction transaction);
////////////////////////////////////////////////////////////////////////////////////////
// POOLING METHODS
////////////////////////////////////////////////////////////////////////////////////////
override protected void Activate(SysTx.Transaction transaction) {
FailoverPermissionDemand(); // Demand for unspecified failover pooled connections
// When we're required to automatically enlist in transactions and
// there is one we enlist in it. On the other hand, if there isn't a
// transaction and we are currently enlisted in one, then we
// unenlist from it.
//
// Regardless of whether we're required to automatically enlist,
// when there is not a current transaction, we cannot leave the
// connection enlisted in a transaction.
if (null != transaction){
if (ConnectionOptions.Enlist) {
Enlist(transaction);
}
}
else {
Enlist(null);
}
}
override protected void Activate(SysTx.Transaction transaction) {
throw ADP.NotSupported();
}