wl2405.patch

storage/ndb/include/ndbapi/Ndb.hpp:
  Import patch wl2405.patch
storage/ndb/include/ndbapi/NdbIndexScanOperation.hpp:
  Import patch wl2405.patch
storage/ndb/include/ndbapi/NdbScanOperation.hpp:
  Import patch wl2405.patch
storage/ndb/include/portlib/NdbThread.h:
  Import patch wl2405.patch
storage/ndb/src/common/portlib/NdbThread.c:
  Import patch wl2405.patch
storage/ndb/src/common/transporter/TransporterRegistry.cpp:
  Import patch wl2405.patch
storage/ndb/src/ndbapi/Ndb.cpp:
  Import patch wl2405.patch
storage/ndb/src/ndbapi/NdbDictionaryImpl.cpp:
  Import patch wl2405.patch
storage/ndb/src/ndbapi/NdbScanOperation.cpp:
  Import patch wl2405.patch
storage/ndb/src/ndbapi/NdbWaiter.hpp:
  Import patch wl2405.patch
storage/ndb/src/ndbapi/Ndbif.cpp:
  Import patch wl2405.patch
storage/ndb/src/ndbapi/Ndbinit.cpp:
  Import patch wl2405.patch
storage/ndb/src/ndbapi/TransporterFacade.cpp:
  Import patch wl2405.patch
storage/ndb/src/ndbapi/TransporterFacade.hpp:
  Import patch wl2405.patch

14 files changed, 640 insertions, 225 deletions

diff --git a/storage/ndb/include/ndbapi/Ndb.hpp b/storage/ndb/include/ndbapi/Ndb.hpp
index db2212075e8..1c9d5ed8ad0 100644
--- a/storage/ndb/include/ndbapi/Ndb.hpp
+++ b/storage/ndb/include/ndbapi/Ndb.hpp
@@ -984,6 +984,8 @@ class BaseString;
 class NdbEventOperation;
 class NdbBlob;
 class NdbReceiver;
+class TransporterFacade;
+class PollGuard;
 
 typedef void (* NdbEventCallback)(NdbEventOperation*, Ndb*, void*);
 
@@ -1462,7 +1464,12 @@ public:
 /*****************************************************************************
  *	These are service routines used by the other classes in the NDBAPI.
  ****************************************************************************/
+ Uint32 get_cond_wait_index() { return cond_wait_index; }
+ void set_cond_wait_index(Uint32 index) { cond_wait_index = index; }
 private:
+  Uint32 cond_wait_index;
+  Ndb *cond_signal_ndb;
+  void cond_signal();
   
   void setup(Ndb_cluster_connection *ndb_cluster_connection,
 	     const char* aCatalogName, const char* aSchemaName);
@@ -1513,13 +1520,11 @@ private:
   // synchronous and asynchronous interface
   void handleReceivedSignal(NdbApiSignal* anApiSignal, struct LinearSectionPtr ptr[3]);
   
-  // Receive response signals
-  int			receiveResponse(int waitTime = WAITFOR_RESPONSE_TIMEOUT);
-
   int			sendRecSignal(Uint16 aNodeId,
 				      Uint32 aWaitState,
 				      NdbApiSignal* aSignal,
-                                      Uint32 nodeSequence);
+                                      Uint32 nodeSequence,
+                                      Uint32 *ret_conn_seq= 0);
   
   // Sets Restart GCI in Ndb object
   void			RestartGCI(int aRestartGCI);
@@ -1576,7 +1581,9 @@ private:
   Uint32  pollCompleted(NdbTransaction** aCopyArray);
   void    sendPrepTrans(int forceSend);
   void    reportCallback(NdbTransaction** aCopyArray, Uint32 aNoOfComplTrans);
-  void    waitCompletedTransactions(int milliSecs, int noOfEventsToWaitFor);
+  int     poll_trans(int milliSecs, int noOfEventsToWaitFor, PollGuard *pg);
+  void    waitCompletedTransactions(int milliSecs, int noOfEventsToWaitFor,
+		                    PollGuard *pg);
   void    completedTransaction(NdbTransaction* aTransaction);
   void    completedScanTransaction(NdbTransaction* aTransaction);
 
diff --git a/storage/ndb/include/ndbapi/NdbIndexScanOperation.hpp b/storage/ndb/include/ndbapi/NdbIndexScanOperation.hpp
index 0a31f228921..c231b927581 100644
--- a/storage/ndb/include/ndbapi/NdbIndexScanOperation.hpp
+++ b/storage/ndb/include/ndbapi/NdbIndexScanOperation.hpp
@@ -161,7 +161,7 @@ private:
 
   void fix_get_values();
   int next_result_ordered(bool fetchAllowed, bool forceSend = false);
-  int send_next_scan_ordered(Uint32 idx, bool forceSend = false);
+  int send_next_scan_ordered(Uint32 idx);
   int compare(Uint32 key, Uint32 cols, const NdbReceiver*, const NdbReceiver*);
 
   Uint32 m_sort_columns;
diff --git a/storage/ndb/include/ndbapi/NdbScanOperation.hpp b/storage/ndb/include/ndbapi/NdbScanOperation.hpp
index bf8f362cefc..b32f6050704 100644
--- a/storage/ndb/include/ndbapi/NdbScanOperation.hpp
+++ b/storage/ndb/include/ndbapi/NdbScanOperation.hpp
@@ -21,6 +21,7 @@
 
 class NdbBlob;
 class NdbResultSet;
+class PollGuard;
 
 /**
  * @class NdbScanOperation
@@ -183,7 +184,8 @@ protected:
   int nextResultImpl(bool fetchAllowed = true, bool forceSend = false);
   virtual void release();
   
-  int close_impl(class TransporterFacade*, bool forceSend = false);
+  int close_impl(class TransporterFacade*, bool forceSend,
+                 PollGuard *poll_guard);
 
   // Overloaded methods from NdbCursorOperation
   int executeCursor(int ProcessorId);
@@ -192,7 +194,6 @@ protected:
   int init(const NdbTableImpl* tab, NdbTransaction*);
   int prepareSend(Uint32  TC_ConnectPtr, Uint64  TransactionId);
   int doSend(int ProcessorId);
-  void checkForceSend(bool forceSend);
 
   virtual void setErrorCode(int aErrorCode);
   virtual void setErrorCodeAbort(int aErrorCode);
@@ -234,7 +235,7 @@ protected:
   Uint32 m_sent_receivers_count;  // NOTE needs mutex to access
   NdbReceiver** m_sent_receivers; // receive thread puts them here
   
-  int send_next_scan(Uint32 cnt, bool close, bool forceSend = false);
+  int send_next_scan(Uint32 cnt, bool close);
   void receiver_delivered(NdbReceiver*);
   void receiver_completed(NdbReceiver*);
   void execCLOSE_SCAN_REP();
diff --git a/storage/ndb/include/portlib/NdbThread.h b/storage/ndb/include/portlib/NdbThread.h
index e86deee4354..003a7e3e151 100644
--- a/storage/ndb/include/portlib/NdbThread.h
+++ b/storage/ndb/include/portlib/NdbThread.h
@@ -37,6 +37,14 @@ typedef size_t NDB_THREAD_STACKSIZE;
 
 struct NdbThread;
 
+/*
+  Method to block/unblock thread from receiving KILL signal with
+  signum set in g_ndb_shm_signum in a portable manner.
+*/
+#ifdef NDB_SHM_TRANSPORTER
+void NdbThread_set_shm_sigmask(bool block);
+#endif
+
 /**
  * Create a thread
  *
diff --git a/storage/ndb/src/common/portlib/NdbThread.c b/storage/ndb/src/common/portlib/NdbThread.c
index 55ebc4c8111..85c2de4fd5e 100644
--- a/storage/ndb/src/common/portlib/NdbThread.c
+++ b/storage/ndb/src/common/portlib/NdbThread.c
@@ -36,6 +36,27 @@ struct NdbThread
   void * object;
 };
 
+
+#ifdef NDB_SHM_TRANSPORTER
+void NdbThread_set_shm_sigmask(bool block)
+{
+  DBUG_ENTER("NdbThread_set_shm_sigmask");
+  if (g_ndb_shm_signum)
+  {
+    sigset_t mask;
+    DBUG_PRINT("info",("Block signum %d",g_ndb_shm_signum));
+    sigemptyset(&mask);
+    sigaddset(&mask, g_ndb_shm_signum);
+    if (block)
+      pthread_sigmask(SIG_BLOCK, &mask, 0);
+    else
+      pthread_sigmask(SIG_UNBLOCK, &mask, 0);
+  }
+  DBUG_VOID_RETURN;
+}
+#endif
+
+
 static
 void*
 ndb_thread_wrapper(void* _ss){
@@ -43,14 +64,7 @@ ndb_thread_wrapper(void* _ss){
   {
     DBUG_ENTER("ndb_thread_wrapper");
 #ifdef NDB_SHM_TRANSPORTER
-    if (g_ndb_shm_signum)
-    {
-      sigset_t mask;
-      DBUG_PRINT("info",("Block signum %d",g_ndb_shm_signum));
-      sigemptyset(&mask);
-      sigaddset(&mask, g_ndb_shm_signum);
-      pthread_sigmask(SIG_BLOCK, &mask, 0);
-    }
+    NdbThread_set_shm_sigmask(true);
 #endif
     {
       void *ret;
diff --git a/storage/ndb/src/common/transporter/TransporterRegistry.cpp b/storage/ndb/src/common/transporter/TransporterRegistry.cpp
index 86bfa385c04..963f5020bd4 100644
--- a/storage/ndb/src/common/transporter/TransporterRegistry.cpp
+++ b/storage/ndb/src/common/transporter/TransporterRegistry.cpp
@@ -457,10 +457,7 @@ TransporterRegistry::createSHMTransporter(TransporterConfiguration *config) {
      * Make sure to block g_ndb_shm_signum
      *   TransporterRegistry::init is run from "main" thread
      */
-    sigset_t mask;
-    sigemptyset(&mask);
-    sigaddset(&mask, g_ndb_shm_signum);
-    pthread_sigmask(SIG_BLOCK, &mask, 0);
+    NdbThread_set_shm_sigmask(true);
   }
 
   if(config->shm.signum != g_ndb_shm_signum)
@@ -1490,11 +1487,9 @@ TransporterRegistry::startReceiving()
     DBUG_PRINT("info",("Install signal handler for signum %d",
 		       g_ndb_shm_signum));
     struct sigaction sa;
+    NdbThread_set_shm_sigmask(false);
     sigemptyset(&sa.sa_mask);
-    sigaddset(&sa.sa_mask, g_ndb_shm_signum);
-    pthread_sigmask(SIG_UNBLOCK, &sa.sa_mask, 0);
     sa.sa_handler = shm_sig_handler;
-    sigemptyset(&sa.sa_mask);
     sa.sa_flags = 0;
     int ret;
     while((ret = sigaction(g_ndb_shm_signum, &sa, 0)) == -1 && errno == EINTR);
diff --git a/storage/ndb/src/ndbapi/Ndb.cpp b/storage/ndb/src/ndbapi/Ndb.cpp
index 7893aaae15c..c5d32f59c3c 100644
--- a/storage/ndb/src/ndbapi/Ndb.cpp
+++ b/storage/ndb/src/ndbapi/Ndb.cpp
@@ -173,23 +173,9 @@ Ndb::NDB_connect(Uint32 tNode)
   tSignal->setData(theMyRef, 2);	// Set my block reference
   tNdbCon->Status(NdbTransaction::Connecting); // Set status to connecting
   Uint32 nodeSequence;
-  { // send and receive signal
-    Guard guard(tp->theMutexPtr);
-    nodeSequence = tp->getNodeSequence(tNode);
-    bool node_is_alive = tp->get_node_alive(tNode);
-    if (node_is_alive) { 
-      tReturnCode = tp->sendSignal(tSignal, tNode);  
-      releaseSignal(tSignal); 
-      if (tReturnCode != -1) {
-        theImpl->theWaiter.m_node = tNode;  
-        theImpl->theWaiter.m_state = WAIT_TC_SEIZE;  
-        tReturnCode = receiveResponse(); 
-      }//if
-    } else {
-      releaseSignal(tSignal);
-      tReturnCode = -1;
-    }//if
-  }
+  tReturnCode= sendRecSignal(tNode, WAIT_TC_SEIZE, tSignal,
+                             0, &nodeSequence);
+  releaseSignal(tSignal); 
   if ((tReturnCode == 0) && (tNdbCon->Status() == NdbTransaction::Connected)) {
     //************************************************
     // Send and receive was successful
diff --git a/storage/ndb/src/ndbapi/NdbDictionaryImpl.cpp b/storage/ndb/src/ndbapi/NdbDictionaryImpl.cpp
index ce5827ab7f4..582f4baaef4 100644
--- a/storage/ndb/src/ndbapi/NdbDictionaryImpl.cpp
+++ b/storage/ndb/src/ndbapi/NdbDictionaryImpl.cpp
@@ -989,7 +989,13 @@ NdbDictInterface::dictSignal(NdbApiSignal* signal,
     m_buffer.clear();
 
     // Protected area
-    m_transporter->lock_mutex();
+    /*
+      The PollGuard has an implicit call of unlock_and_signal through the
+      ~PollGuard method. This method is called implicitly by the compiler
+      in all places where the object is out of context due to a return,
+      break, continue or simply end of statement block
+    */
+    PollGuard poll_guard(m_transporter, &m_waiter, refToBlock(m_reference));
     Uint32 aNodeId;
     if (useMasterNodeId) {
       if ((m_masterNodeId == 0) ||
@@ -1002,7 +1008,6 @@ NdbDictInterface::dictSignal(NdbApiSignal* signal,
     }
     if(aNodeId == 0){
       m_error.code= 4009;
-      m_transporter->unlock_mutex();
       DBUG_RETURN(-1);
     }
     {
@@ -1023,21 +1028,15 @@ NdbDictInterface::dictSignal(NdbApiSignal* signal,
 	r = m_transporter->sendSignal(signal, aNodeId);
       }
       if(r != 0){
-	m_transporter->unlock_mutex();
 	continue;
       }
     }
     
     m_error.code= 0;
-    
-    m_waiter.m_node = aNodeId;
-    m_waiter.m_state = wst;
-
-    m_waiter.wait(theWait);
-    m_transporter->unlock_mutex();    
+    int ret_val= poll_guard.wait_n_unlock(theWait, aNodeId, wst);
     // End of Protected area  
     
-    if(m_waiter.m_state == NO_WAIT && m_error.code == 0){
+    if(ret_val == 0 && m_error.code == 0){
       // Normal return
       DBUG_RETURN(0);
     }
@@ -1045,7 +1044,7 @@ NdbDictInterface::dictSignal(NdbApiSignal* signal,
     /**
      * Handle error codes
      */
-    if(m_waiter.m_state == WAIT_NODE_FAILURE)
+    if(ret_val == -2) //WAIT_NODE_FAILURE
       continue;
 
     if(m_waiter.m_state == WST_WAIT_TIMEOUT)
@@ -3166,26 +3165,28 @@ NdbDictInterface::listObjects(NdbApiSignal* signal)
   for (Uint32 i = 0; i < RETRIES; i++) {
     m_buffer.clear();
     // begin protected
-    m_transporter->lock_mutex();
+    /*
+      The PollGuard has an implicit call of unlock_and_signal through the
+      ~PollGuard method. This method is called implicitly by the compiler
+      in all places where the object is out of context due to a return,
+      break, continue or simply end of statement block
+    */
+    PollGuard poll_guard(m_transporter, &m_waiter, refToBlock(m_reference));
     Uint16 aNodeId = m_transporter->get_an_alive_node();
     if (aNodeId == 0) {
       m_error.code= 4009;
-      m_transporter->unlock_mutex();
       return -1;
     }
     if (m_transporter->sendSignal(signal, aNodeId) != 0) {
-      m_transporter->unlock_mutex();
       continue;
     }
     m_error.code= 0;
-    m_waiter.m_node = aNodeId;
-    m_waiter.m_state = WAIT_LIST_TABLES_CONF;
-    m_waiter.wait(WAITFOR_RESPONSE_TIMEOUT);
-    m_transporter->unlock_mutex();    
+    int ret_val= poll_guard.wait_n_unlock(WAITFOR_RESPONSE_TIMEOUT,
+                                          aNodeId, WAIT_LIST_TABLES_CONF);
     // end protected
-    if (m_waiter.m_state == NO_WAIT && m_error.code == 0)
+    if (ret_val == 0 && m_error.code == 0)
       return 0;
-    if (m_waiter.m_state == WAIT_NODE_FAILURE)
+    if (ret_val == -2) //WAIT_NODE_FAILURE
       continue;
     return -1;
   }
diff --git a/storage/ndb/src/ndbapi/NdbScanOperation.cpp b/storage/ndb/src/ndbapi/NdbScanOperation.cpp
index e0a480e02f7..288b8dc8bd8 100644
--- a/storage/ndb/src/ndbapi/NdbScanOperation.cpp
+++ b/storage/ndb/src/ndbapi/NdbScanOperation.cpp
@@ -460,13 +460,20 @@ int NdbScanOperation::nextResultImpl(bool fetchAllowed, bool forceSend)
   
   Uint32 nodeId = theNdbCon->theDBnode;
   TransporterFacade* tp = TransporterFacade::instance();
-  Guard guard(tp->theMutexPtr);
+  /*
+    The PollGuard has an implicit call of unlock_and_signal through the
+    ~PollGuard method. This method is called implicitly by the compiler
+    in all places where the object is out of context due to a return,
+    break, continue or simply end of statement block
+  */
+  PollGuard poll_guard(tp, &theNdb->theImpl->theWaiter,
+                       theNdb->theNdbBlockNumber);
   if(theError.code)
     return -1;
 
   Uint32 seq = theNdbCon->theNodeSequence;
-  if(seq == tp->getNodeSequence(nodeId) && send_next_scan(idx, false,
-							  forceSend) == 0){
+  if(seq == tp->getNodeSequence(nodeId) && send_next_scan(idx, false) == 0)
+  {
       
     idx = m_current_api_receiver;
     last = m_api_receivers_count;
@@ -495,10 +502,9 @@ int NdbScanOperation::nextResultImpl(bool fetchAllowed, bool forceSend)
 	/**
 	 * No completed...
 	 */
-	theNdb->theImpl->theWaiter.m_node = nodeId;
-	theNdb->theImpl->theWaiter.m_state = WAIT_SCAN;
-	int return_code = theNdb->receiveResponse(WAITFOR_SCAN_TIMEOUT);
-	if (return_code == 0 && seq == tp->getNodeSequence(nodeId)) {
+        int ret_code= poll_guard.wait_scan(WAITFOR_SCAN_TIMEOUT, nodeId,
+                                           forceSend);
+	if (ret_code == 0 && seq == tp->getNodeSequence(nodeId)) {
 	  continue;
 	} else {
 	  idx = last;
@@ -557,8 +563,8 @@ int NdbScanOperation::nextResultImpl(bool fetchAllowed, bool forceSend)
 }
 
 int
-NdbScanOperation::send_next_scan(Uint32 cnt, bool stopScanFlag,
-				 bool forceSend){  
+NdbScanOperation::send_next_scan(Uint32 cnt, bool stopScanFlag)
+{
   if(cnt > 0){
     NdbApiSignal tSignal(theNdb->theMyRef);
     tSignal.setSignal(GSN_SCAN_NEXTREQ);
@@ -605,9 +611,6 @@ NdbScanOperation::send_next_scan(Uint32 cnt, bool stopScanFlag,
 	ret = tp->sendSignal(&tSignal, nodeId);
       }
     }
-    
-    if (!ret) checkForceSend(forceSend);
-
     m_sent_receivers_count = last + sent;
     m_api_receivers_count -= cnt;
     m_current_api_receiver = 0;
@@ -617,15 +620,6 @@ NdbScanOperation::send_next_scan(Uint32 cnt, bool stopScanFlag,
   return 0;
 }
 
-void NdbScanOperation::checkForceSend(bool forceSend)
-{
-  if (forceSend) {
-    TransporterFacade::instance()->forceSend(theNdb->theNdbBlockNumber);
-  } else {
-    TransporterFacade::instance()->checkForceSend(theNdb->theNdbBlockNumber);
-  }//if
-}
-
 int 
 NdbScanOperation::prepareSend(Uint32  TC_ConnectPtr, Uint64  TransactionId)
 {
@@ -661,9 +655,15 @@ void NdbScanOperation::close(bool forceSend, bool releaseOp)
 	       m_sent_receivers_count);
     
     TransporterFacade* tp = TransporterFacade::instance();
-    Guard guard(tp->theMutexPtr);
-    close_impl(tp, forceSend);
-    
+    /*
+      The PollGuard has an implicit call of unlock_and_signal through the
+      ~PollGuard method. This method is called implicitly by the compiler
+      in all places where the object is out of context due to a return,
+      break, continue or simply end of statement block
+    */
+    PollGuard poll_guard(tp, &theNdb->theImpl->theWaiter,
+                         theNdb->theNdbBlockNumber);
+    close_impl(tp, forceSend, &poll_guard);
   }
 
   NdbConnection* tCon = theNdbCon;
@@ -1338,20 +1338,26 @@ NdbIndexScanOperation::next_result_ordered(bool fetchAllowed,
     if(fetchAllowed){
       if(DEBUG_NEXT_RESULT) ndbout_c("performing fetch...");
       TransporterFacade* tp = TransporterFacade::instance();
-      Guard guard(tp->theMutexPtr);
+      /*
+        The PollGuard has an implicit call of unlock_and_signal through the
+        ~PollGuard method. This method is called implicitly by the compiler
+        in all places where the object is out of context due to a return,
+        break, continue or simply end of statement block
+      */
+      PollGuard poll_guard(tp, &theNdb->theImpl->theWaiter,
+                           theNdb->theNdbBlockNumber);
       if(theError.code)
 	return -1;
       Uint32 seq = theNdbCon->theNodeSequence;
       Uint32 nodeId = theNdbCon->theDBnode;
       if(seq == tp->getNodeSequence(nodeId) &&
-	 !send_next_scan_ordered(s_idx, forceSend)){
+	 !send_next_scan_ordered(s_idx)){
 	Uint32 tmp = m_sent_receivers_count;
 	s_idx = m_current_api_receiver; 
 	while(m_sent_receivers_count > 0 && !theError.code){
-	  theNdb->theImpl->theWaiter.m_node = nodeId;
-	  theNdb->theImpl->theWaiter.m_state = WAIT_SCAN;
-	  int return_code = theNdb->receiveResponse(WAITFOR_SCAN_TIMEOUT);
-	  if (return_code == 0 && seq == tp->getNodeSequence(nodeId)) {
+          int ret_code= poll_guard.wait_scan(WAITFOR_SCAN_TIMEOUT, nodeId,
+                                             forceSend);
+	  if (ret_code == 0 && seq == tp->getNodeSequence(nodeId)) {
 	    continue;
 	  }
 	  if(DEBUG_NEXT_RESULT) ndbout_c("return -1");
@@ -1438,7 +1444,8 @@ NdbIndexScanOperation::next_result_ordered(bool fetchAllowed,
 }
 
 int
-NdbIndexScanOperation::send_next_scan_ordered(Uint32 idx, bool forceSend){  
+NdbIndexScanOperation::send_next_scan_ordered(Uint32 idx)
+{
   if(idx == theParallelism)
     return 0;
   
@@ -1476,12 +1483,13 @@ NdbIndexScanOperation::send_next_scan_ordered(Uint32 idx, bool forceSend){
   TransporterFacade * tp = TransporterFacade::instance();
   tSignal.setLength(4+1);
   int ret= tp->sendSignal(&tSignal, nodeId);
-  if (!ret) checkForceSend(forceSend);
   return ret;
 }
 
 int
-NdbScanOperation::close_impl(TransporterFacade* tp, bool forceSend){
+NdbScanOperation::close_impl(TransporterFacade* tp, bool forceSend,
+                             PollGuard *poll_guard)
+{
   Uint32 seq = theNdbCon->theNodeSequence;
   Uint32 nodeId = theNdbCon->theDBnode;
   
@@ -1496,9 +1504,8 @@ NdbScanOperation::close_impl(TransporterFacade* tp, bool forceSend){
    */
   while(theError.code == 0 && m_sent_receivers_count)
   {
-    theNdb->theImpl->theWaiter.m_node = nodeId;
-    theNdb->theImpl->theWaiter.m_state = WAIT_SCAN;
-    int return_code = theNdb->receiveResponse(WAITFOR_SCAN_TIMEOUT);
+    int return_code= poll_guard->wait_scan(WAITFOR_SCAN_TIMEOUT, nodeId,
+                                           false);
     switch(return_code){
     case 0:
       break;
@@ -1555,7 +1562,7 @@ NdbScanOperation::close_impl(TransporterFacade* tp, bool forceSend){
   }
   
   // Send close scan
-  if(send_next_scan(api+conf, true, forceSend) == -1)
+  if(send_next_scan(api+conf, true) == -1)
   {
     theNdbCon->theReleaseOnClose = true;
     return -1;
@@ -1566,9 +1573,8 @@ NdbScanOperation::close_impl(TransporterFacade* tp, bool forceSend){
    */
   while(m_sent_receivers_count+m_api_receivers_count+m_conf_receivers_count)
   {
-    theNdb->theImpl->theWaiter.m_node = nodeId;
-    theNdb->theImpl->theWaiter.m_state = WAIT_SCAN;
-    int return_code = theNdb->receiveResponse(WAITFOR_SCAN_TIMEOUT);
+    int return_code= poll_guard->wait_scan(WAITFOR_SCAN_TIMEOUT, nodeId,
+                                           forceSend);
     switch(return_code){
     case 0:
       break;
@@ -1608,12 +1614,19 @@ NdbScanOperation::restart(bool forceSend)
 {
   
   TransporterFacade* tp = TransporterFacade::instance();
-  Guard guard(tp->theMutexPtr);
+  /*
+    The PollGuard has an implicit call of unlock_and_signal through the
+    ~PollGuard method. This method is called implicitly by the compiler
+    in all places where the object is out of context due to a return,
+    break, continue or simply end of statement block
+  */
+  PollGuard poll_guard(tp, &theNdb->theImpl->theWaiter,
+                       theNdb->theNdbBlockNumber);
   Uint32 nodeId = theNdbCon->theDBnode;
   
   {
     int res;
-    if((res= close_impl(tp, forceSend)))
+    if((res= close_impl(tp, forceSend, &poll_guard)))
     {
       return res;
     }
@@ -1627,7 +1640,6 @@ NdbScanOperation::restart(bool forceSend)
   theError.code = 0;
   if (doSendScan(nodeId) == -1)
     return -1;
-  
   return 0;
 }
 
@@ -1637,8 +1649,15 @@ NdbIndexScanOperation::reset_bounds(bool forceSend){
   
   {
     TransporterFacade* tp = TransporterFacade::instance();
-    Guard guard(tp->theMutexPtr);
-    res= close_impl(tp, forceSend);
+    /*
+      The PollGuard has an implicit call of unlock_and_signal through the
+      ~PollGuard method. This method is called implicitly by the compiler
+      in all places where the object is out of context due to a return,
+      break, continue or simply end of statement block
+    */
+    PollGuard poll_guard(tp, &theNdb->theImpl->theWaiter,
+                         theNdb->theNdbBlockNumber);
+    res= close_impl(tp, forceSend, &poll_guard);
   }
 
   if(!res)
diff --git a/storage/ndb/src/ndbapi/NdbWaiter.hpp b/storage/ndb/src/ndbapi/NdbWaiter.hpp
index 8b7b2a75879..4ccfb40b5ba 100644
--- a/storage/ndb/src/ndbapi/NdbWaiter.hpp
+++ b/storage/ndb/src/ndbapi/NdbWaiter.hpp
@@ -54,10 +54,19 @@ public:
   void wait(int waitTime);
   void nodeFail(Uint32 node);
   void signal(Uint32 state);
+  void cond_signal();
+  void set_poll_owner(bool poll_owner) { m_poll_owner= poll_owner; }
+  Uint32 get_state() { return m_state; }
+  void set_state(Uint32 state) { m_state= state; }
+  void set_node(Uint32 node) { m_node= node; }
+  Uint32 get_cond_wait_index() { return m_cond_wait_index; }
+  void set_cond_wait_index(Uint32 index) { m_cond_wait_index= index; }
 
   Uint32 m_node;
   Uint32 m_state;
   void * m_mutex;
+  bool m_poll_owner;
+  Uint32 m_cond_wait_index;
   struct NdbCondition * m_condition;  
 };
 
@@ -65,22 +74,8 @@ inline
 void
 NdbWaiter::wait(int waitTime)
 {
-  const bool forever = (waitTime == -1);
-  const NDB_TICKS maxTime = NdbTick_CurrentMillisecond() + waitTime;
-  while (1) {
-    if (m_state == NO_WAIT || m_state == WAIT_NODE_FAILURE)
-      break;
-    if (forever) {
-      NdbCondition_Wait(m_condition, (NdbMutex*)m_mutex);
-    } else {
-      if (waitTime <= 0) {
-        m_state = WST_WAIT_TIMEOUT;
-        break;
-      }
-      NdbCondition_WaitTimeout(m_condition, (NdbMutex*)m_mutex, waitTime);
-      waitTime = maxTime - NdbTick_CurrentMillisecond();
-    }
-  }
+  assert(!m_poll_owner);
+  NdbCondition_WaitTimeout(m_condition, (NdbMutex*)m_mutex, waitTime);
 }
 
 inline
@@ -88,7 +83,8 @@ void
 NdbWaiter::nodeFail(Uint32 aNodeId){
   if (m_state != NO_WAIT && m_node == aNodeId){
     m_state = WAIT_NODE_FAILURE;
-    NdbCondition_Signal(m_condition);
+    if (!m_poll_owner)
+      NdbCondition_Signal(m_condition);
   }
 }
 
@@ -96,7 +92,14 @@ inline
 void 
 NdbWaiter::signal(Uint32 state){
   m_state = state;
-  NdbCondition_Signal(m_condition);
+  if (!m_poll_owner)
+    NdbCondition_Signal(m_condition);
 }
 
+inline
+void
+NdbWaiter::cond_signal()
+{
+  NdbCondition_Signal(m_condition);
+}
 #endif
diff --git a/storage/ndb/src/ndbapi/Ndbif.cpp b/storage/ndb/src/ndbapi/Ndbif.cpp
index fee6f0930ad..ca7b5aee84a 100644
--- a/storage/ndb/src/ndbapi/Ndbif.cpp
+++ b/storage/ndb/src/ndbapi/Ndbif.cpp
@@ -332,6 +332,7 @@ Ndb::handleReceivedSignal(NdbApiSignal* aSignal, LinearSectionPtr ptr[3])
   const Uint32 tFirstData = *tDataPtr;
   const Uint32 tLen = aSignal->getLength();
   void * tFirstDataPtr;
+  NdbWaiter *t_waiter;
 
   /*
     In order to support 64 bit processes in the application we need to use
@@ -470,7 +471,7 @@ Ndb::handleReceivedSignal(NdbApiSignal* aSignal, LinearSectionPtr ptr[3])
       ndbout_c("Recevied TCKEY_FAILREF wo/ operation");
 #endif
       return;
-      break;
+      return;
     }
   case GSN_TCKEYREF:
     {
@@ -677,12 +678,12 @@ Ndb::handleReceivedSignal(NdbApiSignal* aSignal, LinearSectionPtr ptr[3])
   case GSN_LIST_TABLES_CONF:
     NdbDictInterface::execSignal(&theDictionary->m_receiver,
 				 aSignal, ptr);
-    break;
+    return;
     
   case GSN_SUB_META_DATA:
   case GSN_SUB_REMOVE_CONF:
   case GSN_SUB_REMOVE_REF:
-    break; // ignore these signals
+    return; // ignore these signals
   case GSN_SUB_GCP_COMPLETE_REP:
   case GSN_SUB_START_CONF:
   case GSN_SUB_START_REF:
@@ -691,7 +692,7 @@ Ndb::handleReceivedSignal(NdbApiSignal* aSignal, LinearSectionPtr ptr[3])
   case GSN_SUB_STOP_REF:
     NdbDictInterface::execSignal(&theDictionary->m_receiver,
 				 aSignal, ptr);
-    break;
+    return;
 
   case GSN_DIHNDBTAMPER:
     {
@@ -833,11 +834,32 @@ Ndb::handleReceivedSignal(NdbApiSignal* aSignal, LinearSectionPtr ptr[3])
   } 
   default:
     goto InvalidSignal;
-  }//switch
-  
-  if (theImpl->theWaiter.m_state == NO_WAIT) {
-    // Wake up the thread waiting for response
-    NdbCondition_Signal(theImpl->theWaiter.m_condition);
+  }//swich
+
+  t_waiter= &theImpl->theWaiter;
+  if (t_waiter->get_state() == NO_WAIT && tWaitState != NO_WAIT)
+  {
+    /*
+      If our waiter object is the owner of the "poll rights", then we
+      can simply return, we will return from this routine to the
+      place where external_poll was called. From there it will move
+      the "poll ownership" to a new thread if available.
+
+      If our waiter object doesn't own the "poll rights", then we must
+      signal the thread from where this waiter object called
+      its conditional wait. This will wake up this thread so that it
+      can continue its work.
+    */
+    TransporterFacade *tp= TransporterFacade::instance();
+    if (tp->get_poll_owner() != t_waiter)
+    {
+      /*
+         Wake up the thread waiting for response and remove it from queue
+         of objects waiting for receive completion
+      */
+      tp->remove_from_cond_wait_queue(t_waiter);
+      t_waiter->cond_signal();
+    }
   }//if
   return;
 
@@ -892,7 +914,19 @@ Ndb::completedTransaction(NdbTransaction* aCon)
     if ((theMinNoOfEventsToWakeUp != 0) &&
         (theNoOfCompletedTransactions >= theMinNoOfEventsToWakeUp)) {
       theMinNoOfEventsToWakeUp = 0;
-      NdbCondition_Signal(theImpl->theWaiter.m_condition);
+      TransporterFacade *tp = TransporterFacade::instance();
+      NdbWaiter *t_waiter= &theImpl->theWaiter;
+      if (tp->get_poll_owner() != t_waiter) {
+        /*
+          When we come here, this is executed by the thread owning the "poll
+          rights". This thread is not where our waiter object belongs.
+          Thus we wake up the thread owning this waiter object but first
+          we must remove it from the conditional wait queue so that we
+          don't assign it as poll owner later on.
+        */
+        tp->remove_from_cond_wait_queue(t_waiter);
+        t_waiter->cond_signal();
+      }
       return;
     }//if
   } else {
@@ -1151,7 +1185,8 @@ Remark:   First send all prepared operations and then check if there are any
 ******************************************************************************/
 void	
 Ndb::waitCompletedTransactions(int aMilliSecondsToWait, 
-			       int noOfEventsToWaitFor)
+			       int noOfEventsToWaitFor,
+                               PollGuard *poll_guard)
 {
   theImpl->theWaiter.m_state = NO_WAIT; 
   /**
@@ -1160,22 +1195,24 @@ Ndb::waitCompletedTransactions(int aMilliSecondsToWait,
    * (see ReportFailure)
    */
   int waitTime = aMilliSecondsToWait;
-  NDB_TICKS maxTime = NdbTick_CurrentMillisecond() + (NDB_TICKS)waitTime;
+  NDB_TICKS currTime = NdbTick_CurrentMillisecond();
+  NDB_TICKS maxTime = currTime + (NDB_TICKS)waitTime;
   theMinNoOfEventsToWakeUp = noOfEventsToWaitFor;
   do {
     if (waitTime < 1000) waitTime = 1000;
-    NdbCondition_WaitTimeout(theImpl->theWaiter.m_condition,
-			     (NdbMutex*)theImpl->theWaiter.m_mutex,
-			     waitTime);
+    poll_guard->wait_for_input(waitTime);
     if (theNoOfCompletedTransactions >= (Uint32)noOfEventsToWaitFor) {
       break;
     }//if
     theMinNoOfEventsToWakeUp = noOfEventsToWaitFor;
     waitTime = (int)(maxTime - NdbTick_CurrentMillisecond());
   } while (waitTime > 0);
-  return;
 }//Ndb::waitCompletedTransactions()
 
+void Ndb::cond_signal()
+{
+  NdbCondition_Signal(theImpl->theWaiter.m_condition);
+}
 /*****************************************************************************
 void sendPreparedTransactions(int forceSend = 0);
 
@@ -1203,28 +1240,39 @@ Remark:   First send all prepared operations and then check if there are any
 int	
 Ndb::sendPollNdb(int aMillisecondNumber, int minNoOfEventsToWakeup, int forceSend)
 {
+  /*
+    The PollGuard has an implicit call of unlock_and_signal through the
+    ~PollGuard method. This method is called implicitly by the compiler
+    in all places where the object is out of context due to a return,
+    break, continue or simply end of statement block
+  */
+  PollGuard pg(TransporterFacade::instance(), &theImpl->theWaiter,
+               theNdbBlockNumber);
+  sendPrepTrans(forceSend);
+  return poll_trans(aMillisecondNumber, minNoOfEventsToWakeup, &pg);
+}
+
+int
+Ndb::poll_trans(int aMillisecondNumber, int minNoOfEventsToWakeup,
+                PollGuard *pg)
+{
   NdbTransaction* tConArray[1024];
   Uint32         tNoCompletedTransactions;
-
-  //theCurrentConnectCounter = 0;
-  //theCurrentConnectIndex++;
-  TransporterFacade::instance()->lock_mutex();
-  sendPrepTrans(forceSend);
   if ((minNoOfEventsToWakeup <= 0) ||
       ((Uint32)minNoOfEventsToWakeup > theNoOfSentTransactions)) {
     minNoOfEventsToWakeup = theNoOfSentTransactions;
   }//if
   if ((theNoOfCompletedTransactions < (Uint32)minNoOfEventsToWakeup) &&
       (aMillisecondNumber > 0)) {
-    waitCompletedTransactions(aMillisecondNumber, minNoOfEventsToWakeup);
+    waitCompletedTransactions(aMillisecondNumber, minNoOfEventsToWakeup, pg);
     tNoCompletedTransactions = pollCompleted(tConArray);
   } else {
     tNoCompletedTransactions = pollCompleted(tConArray);
   }//if
-  TransporterFacade::instance()->unlock_mutex();
+  pg->unlock_and_signal();
   reportCallback(tConArray, tNoCompletedTransactions);
   return tNoCompletedTransactions;
-}//Ndb::sendPollNdb()
+}
 
 /*****************************************************************************
 int pollNdb(int aMillisecondNumber, int minNoOfEventsToWakeup);
@@ -1236,67 +1284,23 @@ Remark:   Check if there are any transactions already completed. Wait for not
 int	
 Ndb::pollNdb(int aMillisecondNumber, int minNoOfEventsToWakeup)
 {
-  NdbTransaction* tConArray[1024];
-  Uint32         tNoCompletedTransactions;
-
-  //theCurrentConnectCounter = 0;
-  //theCurrentConnectIndex++;
-  TransporterFacade::instance()->lock_mutex();
-  if ((minNoOfEventsToWakeup == 0) ||
-      ((Uint32)minNoOfEventsToWakeup > theNoOfSentTransactions)) {
-    minNoOfEventsToWakeup = theNoOfSentTransactions;
-  }//if
-  if ((theNoOfCompletedTransactions < (Uint32)minNoOfEventsToWakeup) &&
-      (aMillisecondNumber > 0)) {
-    waitCompletedTransactions(aMillisecondNumber, minNoOfEventsToWakeup);
-    tNoCompletedTransactions = pollCompleted(tConArray);
-  } else {
-    tNoCompletedTransactions = pollCompleted(tConArray);
-  }//if
-  TransporterFacade::instance()->unlock_mutex();
-  reportCallback(tConArray, tNoCompletedTransactions);
-  return tNoCompletedTransactions;
-}//Ndb::sendPollNdbWithoutWait()
-
-/*****************************************************************************
-int receiveOptimisedResponse();
-
-Return:  0 - Response received
-        -1 - Timeout occured waiting for response
-        -2 - Node failure interupted wait for response
-
-******************************************************************************/
-int	
-Ndb::receiveResponse(int waitTime){
-  int tResultCode;
-  TransporterFacade::instance()->checkForceSend(theNdbBlockNumber);
-  
-  theImpl->theWaiter.wait(waitTime);
-  
-  if(theImpl->theWaiter.m_state == NO_WAIT) {
-    tResultCode = 0;
-  } else {
-
-#ifdef VM_TRACE
-    ndbout << "ERR: receiveResponse - theImpl->theWaiter.m_state = ";
-    ndbout << theImpl->theWaiter.m_state << endl;
-#endif
-
-    if (theImpl->theWaiter.m_state == WAIT_NODE_FAILURE){
-      tResultCode = -2;
-    } else {
-      tResultCode = -1;
-    }
-    theImpl->theWaiter.m_state = NO_WAIT;
-  }
-  return tResultCode;
-}//Ndb::receiveResponse()
+  /*
+    The PollGuard has an implicit call of unlock_and_signal through the
+    ~PollGuard method. This method is called implicitly by the compiler
+    in all places where the object is out of context due to a return,
+    break, continue or simply end of statement block
+  */
+  PollGuard pg(TransporterFacade::instance(), &theImpl->theWaiter,
+               theNdbBlockNumber);
+  return poll_trans(aMillisecondNumber, minNoOfEventsToWakeup, &pg);
+}
 
 int
 Ndb::sendRecSignal(Uint16 node_id,
 		   Uint32 aWaitState,
 		   NdbApiSignal* aSignal,
-                   Uint32 conn_seq)
+                   Uint32 conn_seq,
+                   Uint32 *ret_conn_seq)
 {
   /*
   In most situations 0 is returned.
@@ -1309,19 +1313,28 @@ Ndb::sendRecSignal(Uint16 node_id,
   */
 
   int return_code;
+  Uint32 read_conn_seq;
   TransporterFacade* tp = TransporterFacade::instance();
-  Uint32 send_size = 1; // Always sends one signal only 
-  tp->lock_mutex();
+  Uint32 send_size = 1; // Always sends one signal only
   // Protected area
+  /*
+    The PollGuard has an implicit call of unlock_and_signal through the
+    ~PollGuard method. This method is called implicitly by the compiler
+    in all places where the object is out of context due to a return,
+    break, continue or simply end of statement block
+  */
+  PollGuard poll_guard(tp,&theImpl->theWaiter,theNdbBlockNumber);
+  read_conn_seq= tp->getNodeSequence(node_id);
+  if (ret_conn_seq)
+    *ret_conn_seq= read_conn_seq;
   if ((tp->get_node_alive(node_id)) &&
-      ((tp->getNodeSequence(node_id) == conn_seq) ||
+      ((read_conn_seq == conn_seq) ||
        (conn_seq == 0))) {
     if (tp->check_send_size(node_id, send_size)) {
       return_code = tp->sendSignal(aSignal, node_id);
       if (return_code != -1) {
-        theImpl->theWaiter.m_node = node_id;
-        theImpl->theWaiter.m_state = aWaitState;
-        return_code = receiveResponse();
+        return poll_guard.wait_n_unlock(WAITFOR_RESPONSE_TIMEOUT,node_id,
+                                         aWaitState, false);
       } else {
 	return_code = -3;
       }
@@ -1330,16 +1343,15 @@ Ndb::sendRecSignal(Uint16 node_id,
     }//if
   } else {
     if ((tp->get_node_stopping(node_id)) &&
-        ((tp->getNodeSequence(node_id) == conn_seq) ||
+        ((read_conn_seq == conn_seq) ||
          (conn_seq == 0))) {
       return_code = -5;
     } else {
       return_code = -2;
     }//if
   }//if
-  tp->unlock_mutex();
-  // End of protected area
   return return_code;
+  // End of protected area
 }//Ndb::sendRecSignal()
 
 void
diff --git a/storage/ndb/src/ndbapi/Ndbinit.cpp b/storage/ndb/src/ndbapi/Ndbinit.cpp
index bbc1474f45d..6efcc55c32e 100644
--- a/storage/ndb/src/ndbapi/Ndbinit.cpp
+++ b/storage/ndb/src/ndbapi/Ndbinit.cpp
@@ -86,6 +86,9 @@ void Ndb::setup(Ndb_cluster_connection *ndb_cluster_connection,
   theFirstTransId= 0;
   theMyRef= 0;
 
+  cond_wait_index = TransporterFacade::MAX_NO_THREADS;
+  cond_signal_ndb = NULL;
+
   fullyQualifiedNames = true;
 
 #ifdef POORMANSPURIFY
@@ -217,6 +220,8 @@ NdbWaiter::NdbWaiter(){
   m_node = 0;
   m_state = NO_WAIT;
   m_mutex = 0;
+  m_poll_owner= false;
+  m_cond_wait_index= TransporterFacade::MAX_NO_THREADS;
   m_condition = NdbCondition_Create();
 }
 
diff --git a/storage/ndb/src/ndbapi/TransporterFacade.cpp b/storage/ndb/src/ndbapi/TransporterFacade.cpp
index b143f1a9944..91091aaea06 100644
--- a/storage/ndb/src/ndbapi/TransporterFacade.cpp
+++ b/storage/ndb/src/ndbapi/TransporterFacade.cpp
@@ -450,20 +450,33 @@ runReceiveResponse_C(void * me)
   return 0;
 }
 
+/*
+  The receiver thread is changed to only wake up once every 10 milliseconds
+  to poll. It will first check that nobody owns the poll "right" before
+  polling. This means that methods using the receiveResponse and
+  sendRecSignal will have a slightly longer response time if they are
+  executed without any parallel key lookups. Currently also scans are
+  affected but this is to be fixed.
+*/
 void TransporterFacade::threadMainReceive(void)
 {
   theTransporterRegistry->startReceiving();
+#ifdef NDB_SHM_TRANSPORTER
+  NdbThread_set_shm_sigmask(true);
+#endif
   NdbMutex_Lock(theMutexPtr);
   theTransporterRegistry->update_connections();
   NdbMutex_Unlock(theMutexPtr);
   while(!theStopReceive) {
     for(int i = 0; i<10; i++){
-      const int res = theTransporterRegistry->pollReceive(10);
-      if(res > 0){
-        NdbMutex_Lock(theMutexPtr);
-        theTransporterRegistry->performReceive();
-        NdbMutex_Unlock(theMutexPtr);
+      NdbSleep_MilliSleep(10);
+      NdbMutex_Lock(theMutexPtr);
+      if (poll_owner == NULL) {
+        const int res = theTransporterRegistry->pollReceive(0);
+        if(res > 0)
+          theTransporterRegistry->performReceive();
       }
+      NdbMutex_Unlock(theMutexPtr);
     }
     NdbMutex_Lock(theMutexPtr);
     theTransporterRegistry->update_connections();
@@ -471,6 +484,126 @@ void TransporterFacade::threadMainReceive(void)
   }//while
   theTransporterRegistry->stopReceiving();
 }
+/*
+  This method is called by worker thread that owns the poll "rights".
+  It waits for events and if something arrives it takes care of it
+  and returns to caller. It will quickly come back here if not all
+  data was received for the worker thread.
+*/
+void TransporterFacade::external_poll(Uint32 wait_time)
+{
+  NdbMutex_Unlock(theMutexPtr);
+  const int res = theTransporterRegistry->pollReceive(wait_time);
+  NdbMutex_Lock(theMutexPtr);
+  if (res > 0) {
+    theTransporterRegistry->performReceive();
+  }
+}
+
+/*
+  This Ndb object didn't get hold of the poll "right" and will wait on a
+  conditional mutex wait instead. It is put into the conditional wait
+  queue so that it is accessible to take over the poll "right" if needed.
+  The method gets a free entry in the free list and puts it first in the
+  doubly linked list. Finally it assigns the ndb object reference to the
+  entry.
+*/
+Uint32 TransporterFacade::put_in_cond_wait_queue(NdbWaiter *aWaiter)
+{
+  /*
+   Get first free entry
+  */
+  Uint32 index = first_free_cond_wait;
+  assert(index < MAX_NO_THREADS);
+  first_free_cond_wait = cond_wait_array[index].next_cond_wait;
+
+  /*
+   Put in doubly linked list
+  */
+  cond_wait_array[index].next_cond_wait = MAX_NO_THREADS;
+  cond_wait_array[index].prev_cond_wait = last_in_cond_wait;
+  if (last_in_cond_wait == MAX_NO_THREADS) {
+    first_in_cond_wait = index;
+  } else
+    cond_wait_array[last_in_cond_wait].next_cond_wait = index;
+  last_in_cond_wait = index;
+
+  cond_wait_array[index].cond_wait_object = aWaiter;
+  aWaiter->set_cond_wait_index(index);
+  return index;
+}
+
+/*
+  Somebody is about to signal the thread to wake it up, it could also
+  be that it woke up on a timeout and found himself still in the list.
+  Removes the entry from the doubly linked list.
+  Inserts the entry into the free list.
+  NULLifies the ndb object reference entry and sets the index in the
+  Ndb object to NIL (=MAX_NO_THREADS)
+*/
+void TransporterFacade::remove_from_cond_wait_queue(NdbWaiter *aWaiter)
+{
+  Uint32 index = aWaiter->get_cond_wait_index();
+  assert(index < MAX_NO_THREADS &&
+         cond_wait_array[index].cond_wait_object == aWaiter);
+  /*
+   Remove from doubly linked list
+  */
+  Uint32 prev_elem, next_elem;
+  prev_elem = cond_wait_array[index].prev_cond_wait;
+  next_elem = cond_wait_array[index].next_cond_wait;
+  if (prev_elem != MAX_NO_THREADS)
+    cond_wait_array[prev_elem].next_cond_wait = next_elem;
+  else
+    first_in_cond_wait = next_elem;
+  if (next_elem != MAX_NO_THREADS)
+    cond_wait_array[next_elem].prev_cond_wait = prev_elem;
+  else
+    last_in_cond_wait = prev_elem;
+  /*
+   Insert into free list
+  */
+  cond_wait_array[index].next_cond_wait = first_free_cond_wait;
+  cond_wait_array[index].prev_cond_wait = MAX_NO_THREADS;
+  first_free_cond_wait = index;
+
+  cond_wait_array[index].cond_wait_object = NULL;
+  aWaiter->set_cond_wait_index(MAX_NO_THREADS);
+}
+
+/*
+  Get the latest Ndb object from the conditional wait queue
+  and also remove it from the list.
+*/
+NdbWaiter* TransporterFacade::rem_last_from_cond_wait_queue()
+{
+  NdbWaiter *tWaiter;
+  Uint32 index = last_in_cond_wait;
+  if (last_in_cond_wait == MAX_NO_THREADS)
+    return NULL;
+  tWaiter = cond_wait_array[index].cond_wait_object;
+  remove_from_cond_wait_queue(tWaiter);
+  return tWaiter;
+}
+
+void TransporterFacade::init_cond_wait_queue()
+{
+  Uint32 i;
+  /*
+   Initialise the doubly linked list as empty
+  */
+  first_in_cond_wait = MAX_NO_THREADS;
+  last_in_cond_wait = MAX_NO_THREADS;
+  /*
+   Initialise free list
+  */
+  first_free_cond_wait = 0;
+  for (i = 0; i < MAX_NO_THREADS; i++) {
+    cond_wait_array[i].cond_wait_object = NULL;
+    cond_wait_array[i].next_cond_wait = i+1;
+    cond_wait_array[i].prev_cond_wait = MAX_NO_THREADS;
+  }
+}
 
 TransporterFacade::TransporterFacade() :
   theTransporterRegistry(0),
@@ -480,7 +613,8 @@ TransporterFacade::TransporterFacade() :
   m_fragmented_signal_id(0)
 {
   DBUG_ENTER("TransporterFacade::TransporterFacade");
-
+  init_cond_wait_queue();
+  poll_owner = NULL;
   theOwnId = 0;
 
   theMutexPtr = NdbMutex_Create();
@@ -1119,5 +1253,183 @@ TransporterFacade::ThreadData::close(int number){
   return 0;
 }
 
+PollGuard::PollGuard(TransporterFacade *tp, NdbWaiter *aWaiter,
+                     Uint32 block_no)
+{
+  m_tp= tp;
+  m_waiter= aWaiter;
+  m_locked= true;
+  m_block_no= block_no;
+  tp->lock_mutex();
+}
+
+/*
+  This is a common routine for possibly forcing the send of buffered signals
+  and receiving response the thread is waiting for. It is designed to be
+  useful from:
+  1) PK, UK lookups using the asynchronous interface
+     This routine uses the wait_for_input routine instead since it has
+     special end conditions due to the asynchronous nature of its usage.
+  2) Scans
+  3) dictSignal
+  It uses a NdbWaiter object to wait on the events and this object is
+  linked into the conditional wait queue. Thus this object contains
+  a reference to its place in the queue.
+
+  It replaces the method receiveResponse previously used on the Ndb object
+*/
+int PollGuard::wait_n_unlock(int wait_time, NodeId nodeId, Uint32 state,
+                             bool forceSend)
+{
+  int ret_val;
+  m_waiter->set_node(nodeId);
+  m_waiter->set_state(state);
+  ret_val= wait_for_input_in_loop(wait_time, forceSend);
+  unlock_and_signal();
+  return ret_val;
+}
+
+int PollGuard::wait_scan(int wait_time, NodeId nodeId, bool forceSend)
+{
+  m_waiter->set_node(nodeId);
+  m_waiter->set_state(WAIT_SCAN);
+  return wait_for_input_in_loop(wait_time, forceSend);
+}
+
+int PollGuard::wait_for_input_in_loop(int wait_time, bool forceSend)
+{
+  int ret_val, response_time;
+  if (forceSend)
+    m_tp->forceSend(m_block_no);
+  else
+    m_tp->checkForceSend(m_block_no);
+  if (wait_time == -1) //Means wait forever
+    response_time= WAITFOR_RESPONSE_TIMEOUT;
+  else
+    response_time= wait_time;
+  NDB_TICKS curr_time = NdbTick_CurrentMillisecond();
+  NDB_TICKS max_time = curr_time + (NDB_TICKS)wait_time;
+  do
+  {
+    wait_for_input(response_time);
+    Uint32 state= m_waiter->get_state();
+    if (state == NO_WAIT)
+    {
+      return 0;
+    }
+    else if (state == WAIT_NODE_FAILURE)
+    {
+      ret_val= -2;
+      break;
+    }
+    if (wait_time == -1)
+    {
+#ifdef VM_TRACE
+      ndbout << "Waited WAITFOR_RESPONSE_TIMEOUT, continuing wait" << endl;
+#endif
+      continue;
+    }
+    wait_time= max_time - NdbTick_CurrentMillisecond();
+    if (wait_time <= 0)
+    {
+#ifdef VM_TRACE
+      ndbout << "Time-out state is " << m_waiter->get_state() << endl;
+#endif
+      m_waiter->set_state(WST_WAIT_TIMEOUT);
+      ret_val= -1;
+      break;
+    }
+  } while (1);
+#ifdef VM_TRACE
+  ndbout << "ERR: receiveResponse - theImpl->theWaiter.m_state = ";
+  ndbout << m_waiter->get_state() << endl;
+#endif
+  m_waiter->set_state(NO_WAIT);
+  return ret_val;
+}
+
+void PollGuard::wait_for_input(int wait_time)
+{
+  NdbWaiter *t_poll_owner= m_tp->get_poll_owner();
+  if (t_poll_owner != NULL && t_poll_owner != m_waiter)
+  {
+    /*
+      We didn't get hold of the poll "right". We will sleep on a
+      conditional mutex until the thread owning the poll "right"
+      will wake us up after all data is received. If no data arrives
+      we will wake up eventually due to the timeout.
+      After receiving all data we take the object out of the cond wait
+      queue if it hasn't happened already. It is usually already out of the
+      queue but at time-out it could be that the object is still there.
+    */
+    Uint32 cond_wait_index= m_tp->put_in_cond_wait_queue(m_waiter);
+    m_waiter->wait(wait_time);
+    if (m_waiter->get_cond_wait_index() != TransporterFacade::MAX_NO_THREADS)
+    {
+      m_tp->remove_from_cond_wait_queue(m_waiter);
+    }
+  }
+  else
+  {
+    /*
+      We got the poll "right" and we poll until data is received. After
+      receiving data we will check if all data is received, if not we
+      poll again.
+    */
+    if (t_poll_owner)
+    {
+#ifdef NDB_SHM_TRANSPORTER
+      /*
+        If shared memory transporters are used we need to set our sigmask
+        such that we wake up also on interrupts on the shared memory
+        interrupt signal.
+      */
+      NdbThread_set_shm_sigmask(false);
+#endif
+      m_tp->set_poll_owner(m_waiter);
+      m_waiter->set_poll_owner(true);
+    }
+    m_tp->external_poll((Uint32)wait_time);
+  }
+}
+
+void PollGuard::unlock_and_signal()
+{
+  NdbWaiter *t_signal_cond_waiter= 0;
+  if (!m_locked)
+    return;
+  /*
+   When completing the poll for this thread we must return the poll
+   ownership if we own it. We will give it to the last thread that
+   came here (the most recent) which is likely to be the one also
+   last to complete. We will remove that thread from the conditional
+   wait queue and set him as the new owner of the poll "right".
+   We will wait however with the signal until we have unlocked the
+   mutex for performance reasons.
+   See Stevens book on Unix NetworkProgramming: The Sockets Networking
+   API Volume 1 Third Edition on page 703-704 for a discussion on this
+   subject.
+  */
+  if (m_tp->get_poll_owner() == m_waiter)
+  {
+#ifdef NDB_SHM_TRANSPORTER
+    /*
+      If shared memory transporters are used we need to reset our sigmask
+      since we are no longer the thread to receive interrupts.
+    */
+    NdbThread_set_shm_sigmask(true);
+#endif
+    m_waiter->set_poll_owner(false);
+    t_signal_cond_waiter= m_tp->rem_last_from_cond_wait_queue();
+    m_tp->set_poll_owner(t_signal_cond_waiter);
+    if (t_signal_cond_waiter)
+      t_signal_cond_waiter->set_poll_owner(true);
+  }
+  m_tp->unlock_mutex();
+  if (t_signal_cond_waiter)
+    t_signal_cond_waiter->cond_signal();
+  m_locked=false;
+}
+
 template class Vector<NodeStatusFunction>;
 template class Vector<TransporterFacade::ThreadData::Object_Execute>;
diff --git a/storage/ndb/src/ndbapi/TransporterFacade.hpp b/storage/ndb/src/ndbapi/TransporterFacade.hpp
index fa070889dd9..34e1a944276 100644
--- a/storage/ndb/src/ndbapi/TransporterFacade.hpp
+++ b/storage/ndb/src/ndbapi/TransporterFacade.hpp
@@ -34,6 +34,7 @@ class ConfigRetriever;
 
 class Ndb;
 class NdbApiSignal;
+class NdbWaiter;
 
 typedef void (* ExecuteFunction)(void *, NdbApiSignal *, LinearSectionPtr ptr[3]);
 typedef void (* NodeStatusFunction)(void *, Uint32, bool nodeAlive, bool nfComplete);
@@ -47,6 +48,11 @@ extern "C" {
 class TransporterFacade
 {
 public:
+  /**
+   * Max number of Ndb objects.  
+   * (Ndb objects should not be shared by different threads.)
+   */
+  STATIC_CONST( MAX_NO_THREADS = 4711 );
   TransporterFacade();
   virtual ~TransporterFacade();
   bool init(Uint32, const ndb_mgm_configuration *);
@@ -114,10 +120,44 @@ public:
 
   TransporterRegistry* get_registry() { return theTransporterRegistry;};
 
+/*
+  When a thread has sent its signals and is ready to wait for reception
+  of these it does normally always wait on a conditional mutex and
+  the actual reception is handled by the receiver thread in the NDB API.
+  With the below new methods and variables each thread has the possibility
+  of becoming owner of the "right" to poll for signals. Effectually this
+  means that the thread acts temporarily as a receiver thread.
+  For the thread that succeeds in grabbing this "ownership" it will avoid
+  a number of expensive calls to conditional mutex and even more expensive
+  context switches to wake up.
+  When an owner of the poll "right" has completed its own task it is likely
+  that there are others still waiting. In this case we pick one of the
+  threads as new owner of the poll "right". Since we want to switch owner
+  as seldom as possible we always pick the last thread which is likely to
+  be the last to complete its reception.
+*/
+  void external_poll(Uint32 wait_time);
+  NdbWaiter* get_poll_owner(void) const { return poll_owner; }
+  void set_poll_owner(NdbWaiter* new_owner) { poll_owner= new_owner; }
+  Uint32 put_in_cond_wait_queue(NdbWaiter *aWaiter);
+  void remove_from_cond_wait_queue(NdbWaiter *aWaiter);
+  NdbWaiter* rem_last_from_cond_wait_queue();
   // heart beat received from a node (e.g. a signal came)
   void hb_received(NodeId n);
 
 private:
+  void init_cond_wait_queue();
+  struct CondWaitQueueElement {
+    NdbWaiter *cond_wait_object;
+    Uint32 next_cond_wait;
+    Uint32 prev_cond_wait;
+  };
+  NdbWaiter *poll_owner;
+  CondWaitQueueElement cond_wait_array[MAX_NO_THREADS];
+  Uint32 first_in_cond_wait;
+  Uint32 first_free_cond_wait;
+  Uint32 last_in_cond_wait;
+  /* End poll owner stuff */
   /**
    * Send a signal unconditional of node status (used by ClusterMgr)
    */
@@ -172,12 +212,6 @@ private:
   /**
    * Block number handling
    */
-public:
-  /**
-   * Max number of Ndb objects.  
-   * (Ndb objects should not be shared by different threads.)
-   */
-  STATIC_CONST( MAX_NO_THREADS = 4711 );
 private:
 
   struct ThreadData {
@@ -245,6 +279,24 @@ public:
   GlobalDictCache m_globalDictCache;
 };
 
+class PollGuard
+{
+  public:
+  PollGuard(TransporterFacade *tp, NdbWaiter *aWaiter, Uint32 block_no);
+  ~PollGuard() { unlock_and_signal(); }
+  int wait_n_unlock(int wait_time, NodeId nodeId, Uint32 state,
+                    bool forceSend= false);
+  int wait_for_input_in_loop(int wait_time, bool forceSend);
+  void wait_for_input(int wait_time);
+  int wait_scan(int wait_time, NodeId nodeId, bool forceSend);
+  void unlock_and_signal();
+  private:
+  TransporterFacade *m_tp;
+  NdbWaiter *m_waiter;
+  Uint32 m_block_no;
+  bool m_locked;
+};
+
 inline
 TransporterFacade*
 TransporterFacade::instance()