ndb -

  bug#19928 and bug#19929
  fix to critical bugs in tup scan
  that affected lcp,backup and opt. nr


storage/ndb/src/kernel/blocks/dbtup/DbtupScan.cpp:
  1) dont let dirty read scan find uncommitted inserts
  2) force opt. nr scan to wait for locked rows
  3) when finding LCP keep record, use accOpPtr -1, so that it will not be committed towards ACC

storage/ndb/src/kernel/blocks/dbtup/DbtupScan.cpp

@@ -582,12 +582,15 @@ Dbtup::scanNext(Signal* signal, ScanOpPtr scanPtr)
   Fragrecord& frag = *fragPtr.p;
   // tuple found
   Tuple_header* th = 0;
+  Uint32 thbits = 0;
   Uint32 loop_count = 0;
   Uint32 scanGCI = scanPtr.p->m_scanGCI;
   Uint32 foundGCI;
  
-  bool mm = (bits & ScanOp::SCAN_DD);
-  bool lcp = (bits & ScanOp::SCAN_LCP);
+  const bool mm = (bits & ScanOp::SCAN_DD);
+  const bool lcp = (bits & ScanOp::SCAN_LCP);
+  const bool dirty = (bits & ScanOp::SCAN_LOCK) == 0;
+  
   Uint32 lcp_list = fragPtr.p->m_lcp_keep_list;
   Uint32 size = table.m_offsets[mm].m_fix_header_size +
     (bits & ScanOp::SCAN_VS ? Tuple_header::HeaderSize + 1: 0);
@@ -750,22 +753,22 @@ Dbtup::scanNext(Signal* signal, ScanOpPtr scanPtr)
 	{
 	  pos.m_get = ScanPos::Get_next_tuple_fs;
           th = (Tuple_header*)&page->m_data[key.m_page_idx];
+	  thbits = th->m_header_bits;
+	  
 	  if (likely(! (bits & ScanOp::SCAN_NR)))
-	  {
-	    if (! (th->m_header_bits & Tuple_header::FREE)) {
-	      goto found_tuple;
-	    } 
-	    else 
 	  {
 	    jam();
-	      // skip free tuple
+	    if (! (thbits & Tuple_header::FREE))
+	    {
+	      if (! ((thbits & Tuple_header::ALLOC) && dirty))
+		goto found_tuple;
 	    } 
 	  }
 	  else
 	  {
 	    if ((foundGCI = *th->get_mm_gci(tablePtr.p)) > scanGCI)
 	    {
-	      if (! (th->m_header_bits & Tuple_header::FREE))
+	      if (! (thbits & Tuple_header::FREE))
 	      {
 		jam();
 		goto found_tuple;
@@ -775,9 +778,11 @@ Dbtup::scanNext(Signal* signal, ScanOpPtr scanPtr)
 		goto found_deleted_rowid;
 	      }
 	    }
-	    else
+	    else if (thbits != Fix_page::FREE_RECORD && 
+		     th->m_operation_ptr_i != RNIL)
 	    {
 	      jam();
+	      goto found_tuple; // Locked tuple...
 	      // skip free tuple
 	    }
 	  }
@@ -793,8 +798,7 @@ Dbtup::scanNext(Signal* signal, ScanOpPtr scanPtr)
       jam();
       {
         // caller has already set pos.m_get to next tuple
-        if (! (bits & ScanOp::SCAN_LCP && 
-           th->m_header_bits & Tuple_header::LCP_SKIP)) {
+        if (! (bits & ScanOp::SCAN_LCP && thbits & Tuple_header::LCP_SKIP)) {
           Local_key& key_mm = pos.m_key_mm;
           if (! (bits & ScanOp::SCAN_DD)) {
             key_mm = pos.m_key;
@@ -810,7 +814,11 @@ Dbtup::scanNext(Signal* signal, ScanOpPtr scanPtr)
         } else {
           jam();
           // clear it so that it will show up in next LCP
-          th->m_header_bits &= ~(Uint32)Tuple_header::LCP_SKIP;
+          th->m_header_bits = thbits & ~(Uint32)Tuple_header::LCP_SKIP;
+	  if (tablePtr.p->m_bits & Tablerec::TR_Checksum) {
+	    jam();
+	    setChecksum(th, tablePtr.p);
+	  }
         }
       }
       break;
@@ -833,7 +841,7 @@ Dbtup::scanNext(Signal* signal, ScanOpPtr scanPtr)
 	  th = (Tuple_header*)(mmpage->m_data + key_mm.m_page_idx);
 	  if ((foundGCI = *th->get_mm_gci(tablePtr.p)) > scanGCI)
 	  {
-	    if (! (th->m_header_bits & Tuple_header::FREE))
+	    if (! (thbits & Tuple_header::FREE))
 	      break;
 	  }
 	}
@@ -893,7 +901,7 @@ Dbtup::scanNext(Signal* signal, ScanOpPtr scanPtr)
   
   NextScanConf* const conf = (NextScanConf*)signal->getDataPtrSend();
   conf->scanPtr = scan.m_userPtr;
-  conf->accOperationPtr = RNIL + 1;
+  conf->accOperationPtr = (Uint32)-1;
   conf->fragId = frag.fragmentId;
   conf->localKey[0] = lcp_list;
   conf->localKey[1] = 0;