diff --git a/dbcon/joblist/limitedorderby.cpp b/dbcon/joblist/limitedorderby.cpp
index 7da1accfe..d5db83552 100644
--- a/dbcon/joblist/limitedorderby.cpp
+++ b/dbcon/joblist/limitedorderby.cpp
@@ -113,7 +113,6 @@ void LimitedOrderBy::processRow(const rowgroup::Row& row)
     if (fOrderByQueue.size() < fStart + fCount)
     {
         copyRow(row, &fRow0);
-        //memcpy(fRow0.getData(), row.getData(), row.getSize());
         OrderByRow newRow(fRow0, fRule);
         fOrderByQueue.push(newRow);
 
@@ -121,8 +120,6 @@ void LimitedOrderBy::processRow(const rowgroup::Row& row)
         if (fDistinct)
             fDistinctMap->insert(fRow0.getPointer());
 
-        //fDistinctMap->insert(make_pair((fRow0.getData()+2), fRow0.getData()));
-
         fRowGroup.incRowCount();
         fRow0.nextRow();
 
@@ -150,23 +147,16 @@ void LimitedOrderBy::processRow(const rowgroup::Row& row)
     {
         OrderByRow swapRow = fOrderByQueue.top();
         row1.setData(swapRow.fData);
-        fOrderByQueue.pop();
 
-        if (!fDistinct)
+        copyRow(row, &row1);
+
+        if (fDistinct)
         {
-            copyRow(row, &row1);
-            //memcpy(swapRow.fData, row.getData(), row.getSize());
-        }
-        else
-        {
-            fDistinctMap->erase(row.getPointer());
-            copyRow(row, &row1);
+            fDistinctMap->erase(fOrderByQueue.top().fData);
             fDistinctMap->insert(row1.getPointer());
-            //fDistinctMap->erase(fDistinctMap->find(row.getData() + 2));
-            //memcpy(swapRow.fData, row.getData(), row.getSize());
-            //fDistinctMap->insert(make_pair((swapRow.fData+2), swapRow.fData));
         }
 
+        fOrderByQueue.pop();
         fOrderByQueue.push(swapRow);
     }
 }
@@ -228,6 +218,7 @@ void LimitedOrderBy::finalize()
             const OrderByRow& topRow = fOrderByQueue.top();
             row1.setData(topRow.fData);
             copyRow(row1, &fRow0);
+            //cerr << "LimitedOrderBy::finalize fRow0 " << fRow0.toString() << endl;
             fRowGroup.incRowCount();
             offset--;
             fRow0.prevRow(rSize);
diff --git a/dbcon/joblist/tupleaggregatestep.cpp b/dbcon/joblist/tupleaggregatestep.cpp
index 9ddf42cc9..4c1893115 100644
--- a/dbcon/joblist/tupleaggregatestep.cpp
+++ b/dbcon/joblist/tupleaggregatestep.cpp
@@ -5554,6 +5554,8 @@ void TupleAggregateStep::threadedAggregateRowGroups(uint32_t threadID)
                                     rowIn.copyField(distRow[j], k, multiDist->subAggregators()[j]->getGroupByCols()[k].get()->fInputColumnIndex);
                                 }
 
+                                // TBD This approach could potentiall
+                                // put all values in on bucket.
                                 bucketID = distRow[j].hash(hashLens[j] - 1) % fNumOfBuckets;
                                 rowBucketVecs[bucketID][j].push_back(rowIn.getPointer());
                                 rowIn.nextRow();
@@ -5572,6 +5574,8 @@ void TupleAggregateStep::threadedAggregateRowGroups(uint32_t threadID)
                         for (uint64_t i = 0; i < fRowGroupIns[threadID].getRowCount(); ++i)
                         {
                             // The key is the groupby columns, which are the leading columns.
+                            // TBD This approach could potentiall
+                            // put all values in on bucket.
                             int bucketID = rowIn.hash(hashLens[0] - 1) % fNumOfBuckets;
                             rowBucketVecs[bucketID][0].push_back(rowIn.getPointer());
                             rowIn.nextRow();
diff --git a/utils/rowgroup/rowgroup.h b/utils/rowgroup/rowgroup.h
index e1c3073c4..ca05360c2 100644
--- a/utils/rowgroup/rowgroup.h
+++ b/utils/rowgroup/rowgroup.h
@@ -1183,6 +1183,7 @@ inline bool Row::equals(const Row& r2, const std::vector<uint32_t>& keyCols) con
 
 inline bool Row::equals(const Row& r2, uint32_t lastCol) const
 {
+    // This check fires with empty r2 only.
     if (lastCol >= columnCount)
         return true;
 
diff --git a/utils/windowfunction/idborderby.cpp b/utils/windowfunction/idborderby.cpp
index 8a021f8d8..bac14bec8 100644
--- a/utils/windowfunction/idborderby.cpp
+++ b/utils/windowfunction/idborderby.cpp
@@ -461,7 +461,8 @@ uint64_t IdbOrderBy::Hasher::operator()(const Row::Pointer& p) const
 {
     Row& row = ts->row1;
     row.setPointer(p);
-    uint64_t ret = row.hash(colCount);
+    // MCOL-1829 Row::h uses colcount as an array idx down a callstack.
+    uint64_t ret = row.hash();//(colCount - 1);
     //cout << "hash(): returning " << ret << " for row: " << row.toString() << endl;
     return ret;
 }
@@ -471,7 +472,9 @@ bool IdbOrderBy::Eq::operator()(const Row::Pointer& d1, const Row::Pointer& d2)
     Row& r1 = ts->row1, &r2 = ts->row2;
     r1.setPointer(d1);
     r2.setPointer(d2);
-    bool ret = r1.equals(r2, colCount);
+    // MCOL-1829 Row::equals uses 2nd argument as container size boundary
+    // so it must be column count - 1.
+    bool ret = r1.equals(r2, colCount - 1);
     //cout << "equals(): returning " << (int) ret << " for r1: " << r1.toString() << " r2: " << r2.toString()
     //	<< endl;