Fix parquet reader

Author: rui-mo

velox/connectors/hive/HiveDataSource.cpp

@@ -651,10 +651,19 @@ void HiveDataSource::addSplit(std::shared_ptr<ConnectorSplit> split) {
     } else {
       auto fileTypeIdx = fileType->getChildIdxIfExists(fieldName);
       if (!fileTypeIdx.has_value()) {
-        // Column is missing. Most likely due to schema evolution.
-        VELOX_CHECK(readerOpts_.getFileSchema());
-        setNullConstantValue(
-            childSpec, readerOpts_.getFileSchema()->findChild(fieldName));
+        // If field name exists in the user-specified output type,
+        // set the column as null constant.
+        // Related PR: https://github.com/facebookincubator/velox/pull/6427.
+        auto outputTypeIdx = readerOutputType_->getChildIdxIfExists(fieldName);
+        if (outputTypeIdx.has_value()) {
+          setNullConstantValue(
+              childSpec, readerOutputType_->childAt(outputTypeIdx.value()));
+        } else {
+          // Column is missing. Most likely due to schema evolution.
+          VELOX_CHECK(readerOpts_.getFileSchema());
+          setNullConstantValue(
+              childSpec, readerOpts_.getFileSchema()->findChild(fieldName));
+        }
       } else {
         // Column no longer missing, reset constant value set on the spec.
         childSpec->setConstantValue(nullptr);

velox/dwio/common/SelectiveRepeatedColumnReader.cpp

@@ -282,12 +282,12 @@ void SelectiveMapColumnReader::getValues(RowSet rows, VectorPtr* result) {
       "SelectiveMapColumnReader::getValues");
   if (!nestedRows_.empty()) {
     keyReader_->getValues(nestedRows_, &keys);
-    prepareStructResult(requestedType_->type()->childAt(1), &values);
+    prepareStructResult(result->get()->type()->childAt(1), &values);
     elementReader_->getValues(nestedRows_, &values);
   }
   *result = std::make_shared<MapVector>(
       &memoryPool_,
-      requestedType_->type(),
+      result->get()->type(),
       anyNulls_ ? resultNulls_ : nullptr,
       rows.size(),
       offsets_,