ndb - bug#20252

allow user to specify scan batch size in readTuples

ndb/include/ndbapi/NdbIndexScanOperation.hpp

@@ -41,7 +41,9 @@ public:
    * @param parallel No of fragments to scan in parallel (0=max)
    */ 
   virtual int readTuples(LockMode lock_mode = LM_Read, 
-                         Uint32 scan_flags = 0, Uint32 parallel = 0);
+                         Uint32 scan_flags = 0, 
+			 Uint32 parallel = 0,
+			 Uint32 batch = 0);
 
 #ifndef DOXYGEN_SHOULD_SKIP_INTERNAL
   /**
@@ -66,7 +68,7 @@ public:
       (SF_OrderBy & -(Int32)order_by) |
       (SF_Descending & -(Int32)order_desc) |
       (SF_ReadRangeNo & -(Int32)read_range_no);
-    return readTuples(lock_mode, scan_flags, parallel);
+    return readTuples(lock_mode, scan_flags, parallel, batch);
   }
 #endif
 

ndb/include/ndbapi/NdbScanOperation.hpp

@@ -56,7 +56,9 @@ public:
    */ 
   virtual
   int readTuples(LockMode lock_mode = LM_Read, 
-                 Uint32 scan_flags = 0, Uint32 parallel = 0);
+                 Uint32 scan_flags = 0, 
+		 Uint32 parallel = 0,
+		 Uint32 batch = 0);
 
 #ifndef DOXYGEN_SHOULD_SKIP_DEPRECATED
   /**

ndb/src/kernel/blocks/dblqh/DblqhMain.cpp

@@ -7349,15 +7349,15 @@ void Dblqh::scanLockReleasedLab(Signal* signal)
       scanptr.p->m_curr_batch_size_rows = 0;
       scanptr.p->m_curr_batch_size_bytes = 0;
       closeScanLab(signal);
+    } else if (scanptr.p->m_last_row && !scanptr.p->scanLockHold) {
+      jam();
+      closeScanLab(signal);
+      return;
     } else if (scanptr.p->check_scan_batch_completed() &&
                scanptr.p->scanLockHold != ZTRUE) {
       jam();
       scanptr.p->scanState = ScanRecord::WAIT_SCAN_NEXTREQ;
       sendScanFragConf(signal, ZFALSE);
-    } else if (scanptr.p->m_last_row && !scanptr.p->scanLockHold) {
-      jam();
-      closeScanLab(signal);
-      return;
     } else {
       jam();
       /*

ndb/src/ndbapi/NdbReceiver.cpp

@@ -121,7 +121,15 @@ NdbReceiver::calculate_batch_size(Uint32 key_size,
    * no more than MAX_SCAN_BATCH_SIZE is sent from all nodes in total per
    * batch.
    */
-  batch_byte_size= max_batch_byte_size;
+  if (batch_size == 0)
+  {
+    batch_byte_size= max_batch_byte_size;
+  }
+  else
+  {
+    batch_byte_size= batch_size * tot_size;
+  }
+  
   if (batch_byte_size * parallelism > max_scan_batch_size) {
     batch_byte_size= max_scan_batch_size / parallelism;
   }

ndb/src/ndbapi/NdbScanOperation.cpp

@@ -117,7 +117,8 @@ NdbScanOperation::init(const NdbTableImpl* tab, NdbTransaction* myConnection)
 int 
 NdbScanOperation::readTuples(NdbScanOperation::LockMode lm,
 			     Uint32 scan_flags, 
-			     Uint32 parallel)
+			     Uint32 parallel,
+			     Uint32 batch)
 {
   m_ordered = m_descending = false;
   Uint32 fragCount = m_currentTable->m_fragmentCount;
@@ -182,6 +183,9 @@ NdbScanOperation::readTuples(NdbScanOperation::LockMode lm,
   if (tupScan && rangeScan)
     tupScan = false;
 
+  if (rangeScan && (scan_flags & SF_OrderBy))
+    parallel = fragCount;
+  
   theParallelism = parallel;    
   
   if(fix_receivers(parallel) == -1){
@@ -202,6 +206,7 @@ NdbScanOperation::readTuples(NdbScanOperation::LockMode lm,
   req->tableSchemaVersion = m_accessTable->m_version;
   req->storedProcId = 0xFFFF;
   req->buddyConPtr = theNdbCon->theBuddyConPtr;
+  req->first_batch_size = batch; // Save user specified batch size
   
   Uint32 reqInfo = 0;
   ScanTabReq::setParallelism(reqInfo, parallel);
@@ -750,13 +755,14 @@ int NdbScanOperation::prepareSendScan(Uint32 aTC_ConnectPtr,
    * The number of records sent by each LQH is calculated and the kernel
    * is informed of this number by updating the SCAN_TABREQ signal
    */
-  Uint32 batch_size, batch_byte_size, first_batch_size;
+  ScanTabReq * req = CAST_PTR(ScanTabReq, theSCAN_TABREQ->getDataPtrSend());
+  Uint32 batch_size = req->first_batch_size; // User specified
+  Uint32 batch_byte_size, first_batch_size;
   theReceiver.calculate_batch_size(key_size,
                                    theParallelism,
                                    batch_size,
                                    batch_byte_size,
                                    first_batch_size);
-  ScanTabReq * req = CAST_PTR(ScanTabReq, theSCAN_TABREQ->getDataPtrSend());
   ScanTabReq::setScanBatch(req->requestInfo, batch_size);
   req->batch_byte_size= batch_byte_size;
   req->first_batch_size= first_batch_size;
@@ -1206,13 +1212,14 @@ error:
 int
 NdbIndexScanOperation::readTuples(LockMode lm,
 				  Uint32 scan_flags,
-				  Uint32 parallel)
+				  Uint32 parallel,
+				  Uint32 batch)
 {
   const bool order_by = scan_flags & SF_OrderBy;
   const bool order_desc = scan_flags & SF_Descending;
   const bool read_range_no = scan_flags & SF_ReadRangeNo;
   
-  int res = NdbScanOperation::readTuples(lm, scan_flags, 0);
+  int res = NdbScanOperation::readTuples(lm, scan_flags, parallel, batch);
   if(!res && read_range_no)
   {
     m_read_range_no = 1;