Fixed Wrong resultTypes in columns. (#434)

1. Fixed wrong result type in second part of union (for a column that does not appear in the first part)
2. Temporary fix for wrong result type in join with empty subresult (due to early stopping, which is now temporarily disabled).

src/engine/Join.cpp

@@ -71,6 +71,10 @@ void Join::computeResult(ResultTable* result) {
   size_t leftWidth = _left->getResultWidth();
   size_t rightWidth = _right->getResultWidth();
 
+  // TODO<joka921> Currently the _resultTypes are set incorrectly in case
+  // of early stopping. For now, early stopping is thus disabled.
+  // TODO: Implement getting the result types without calculating the result;
+  /*
   // Checking this before calling getResult on the subtrees can
   // avoid the computation of an non-empty subtree.
   if (_left->knownEmptyResult() || _right->knownEmptyResult()) {
@@ -82,6 +86,7 @@ void Join::computeResult(ResultTable* result) {
     result->_sortedBy = {_leftJoinCol};
     return;
   }
+   */
 
   // Check for joins with dummy
   if (isFullScanDummy(_left) || isFullScanDummy(_right)) {
@@ -94,7 +99,11 @@ void Join::computeResult(ResultTable* result) {
   shared_ptr<const ResultTable> leftRes = _left->getResult();
   runtimeInfo.addChild(_left->getRootOperation()->getRuntimeInfo());
 
+  // TODO<joka921> Currently the _resultTypes are set incorrectly in case
+  // of early stopping. For now, early stopping is thus disabled.
+  // TODO: Implement getting the result types without calculating the result;
   // Check if we can stop early.
+  /*
   if (leftRes->size() == 0) {
     LOG(TRACE) << "Left side empty thus join result is empty" << endl;
     runtimeInfo.addDetail("The left side was empty", "");
@@ -104,6 +113,7 @@ void Join::computeResult(ResultTable* result) {
     result->_sortedBy = {_leftJoinCol};
     return;
   }
+   */
 
   LOG(TRACE) << "Computing right side..." << endl;
   shared_ptr<const ResultTable> rightRes = _right->getResult();

src/engine/Union.cpp

@@ -141,7 +141,7 @@ void Union::computeResult(ResultTable* result) {
     if (o[0] != NO_COLUMN) {
       result->_resultTypes.push_back(subRes1->getResultType(o[0]));
     } else if (o[1] != NO_COLUMN) {
-      result->_resultTypes.push_back(subRes1->getResultType(o[1]));
+      result->_resultTypes.push_back(subRes2->getResultType(o[1]));
     } else {
       result->_resultTypes.push_back(ResultTable::ResultType::KB);
     }