[GitHub] twalthr commented on a change in pull request #6483: [FLINK-7243][flink-formats] Add parquet input format

[GitBox <gi...@apache.org>]

twalthr commented on a change in pull request #6483: [FLINK-7243][flink-formats] Add parquet input format
URL: https://github.com/apache/flink/pull/6483#discussion_r224349110
 
 

 ##########
 File path: flink-formats/flink-parquet/src/main/java/org/apache/flink/formats/parquet/utils/ParquetSchemaConverter.java
 ##########
 @@ -0,0 +1,242 @@
+/*
+ * Licensed to the Apache Software Foundation (ASF) under one
+ * or more contributor license agreements.  See the NOTICE file
+ * distributed with this work for additional information
+ * regarding copyright ownership.  The ASF licenses this file
+ * to you under the Apache License, Version 2.0 (the
+ * "License"); you may not use this file except in compliance
+ * with the License.  You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package org.apache.flink.formats.parquet.utils;
+
+import org.apache.flink.api.common.typeinfo.BasicArrayTypeInfo;
+import org.apache.flink.api.common.typeinfo.BasicTypeInfo;
+import org.apache.flink.api.common.typeinfo.TypeInformation;
+import org.apache.flink.api.java.typeutils.MapTypeInfo;
+import org.apache.flink.api.java.typeutils.ObjectArrayTypeInfo;
+import org.apache.flink.api.java.typeutils.RowTypeInfo;
+
+import org.apache.parquet.avro.AvroSchemaConverter;
+import org.apache.parquet.schema.GroupType;
+import org.apache.parquet.schema.MessageType;
+import org.apache.parquet.schema.OriginalType;
+import org.apache.parquet.schema.PrimitiveType;
+import org.apache.parquet.schema.Type;
+import org.apache.parquet.schema.Types;
+
+import java.lang.reflect.Array;
+import java.util.ArrayList;
+import java.util.List;
+
+/**
+ * Schema converter converts Parquet schema to and from Flink internal types.
+ */
+public class ParquetSchemaConverter {
+	public static final String MAP_KEY = "key";
+	public static final String MAP_VALUE = "value";
+	public static final String LIST_ELEMENT = "array";
+	public static final String MESSAGE_ROOT = "root";
+	private static final AvroSchemaConverter SCHEMA_CONVERTER = new AvroSchemaConverter();
+
+	public static TypeInformation<?> fromParquetType(MessageType type) {
+		return convertFields(type.getFields());
+	}
+
+	public static MessageType toParquetType(TypeInformation<?> typeInformation) {
+		return (MessageType) convertField(null, typeInformation, Type.Repetition.OPTIONAL);
+	}
+
+	private static TypeInformation<?> convertFields(List<Type> parquetFields) {
+		List<TypeInformation<?>> types = new ArrayList<>();
+		List<String> names = new ArrayList<>();
+		for (Type field : parquetFields) {
+			TypeInformation<?> subType = convertField(field);
+			if (subType != null) {
+				types.add(subType);
+				names.add(field.getName());
+			}
+		}
+
+		return new RowTypeInfo(types.toArray(new TypeInformation<?>[types.size()]),
+			names.toArray(new String[names.size()]));
+	}
+
+	private static TypeInformation<?> convertField(final Type fieldType) {
+		TypeInformation<?> typeInfo = null;
+		if (fieldType.isPrimitive()) {
+			PrimitiveType primitiveType = fieldType.asPrimitiveType();
 
 Review comment:
   IMHO I think we should aim to map all Parquet types to Flink types. Otherwise the integration is not end-to-end and requires a lot of customization nevertheless. New supported formats such as ORC, Avro, or JSON support all types. Which makes the connector robust.

----------------------------------------------------------------
This is an automated message from the Apache Git Service.
To respond to the message, please log on GitHub and use the
URL above to go to the specific comment.
 
For queries about this service, please contact Infrastructure at:
users@infra.apache.org


With regards,
Apache Git Services