wgtmac commented on code in PR #60: URL: https://github.com/apache/parquet-testing/pull/60#discussion_r1805911221
########## data/old_list_structure.md: ########## @@ -0,0 +1,103 @@ +<!-- + ~ 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. + --> + +`old_list_structure.parquet` is generated with parquet-java version 1.14.3. +It contains a `LIST<LIST<INT32>>` column with a single value `[[1, 2], [3, 4]]` +using the legacy two-level structure encoding for list type. + +The file is created by the following Java code: +```java +package org.example; + +import org.apache.avro.Schema; +import org.apache.avro.generic.GenericData; +import org.apache.avro.generic.GenericRecord; +import org.apache.hadoop.conf.Configuration; +import org.apache.hadoop.fs.Path; +import org.apache.parquet.avro.AvroParquetWriter; +import org.apache.parquet.hadoop.ParquetWriter; + +import java.io.IOException; +import java.util.Arrays; +import java.util.stream.Collectors; +import java.util.stream.Stream; + +public class TwoLevelList { + + public static void main(String[] args) { + Schema schema = new Schema.Parser().parse("{" + + "\"type\":\"record\"," + + "\"name\":\"my_record\"," + + "\"fields\":[" + + " {" + + " \"name\":\"a\"," + + " \"type\":{\"type\":\"array\", \"items\":{\"type\":\"array\", \"items\":\"int\"}}" + + " }" + + "]" + + "}"); + + GenericRecord record = new GenericData.Record(schema); + + // Write [[1, 2], [3, 4]] to the avro record + record.put("a", Stream.of(Arrays.asList(1, 2), Arrays.asList(3, 4)) + .map(list -> { + Schema innerListType = schema.getField("a").schema().getElementType(); + GenericData.Array<Integer> innerList = new GenericData.Array<>(list.size(), innerListType); + innerList.addAll(list); + return innerList; + }).collect(Collectors.toList())); + + Path file = new Path("/tmp/old_list_structure.parquet"); + Configuration conf = new Configuration(); + conf.set("parquet.avro.write-old-list-structure", "true"); // this is the default value + try (ParquetWriter<GenericRecord> writer = AvroParquetWriter.<GenericRecord>builder(file) + .withSchema(schema) + .withConf(conf) + .build()) { + writer.write(record); + } catch (IOException e) { + throw new RuntimeException(e); + } + } + +} +``` + +Here is the file metadata printed by parquet-cli: +``` +File path: /tmp/old_list_structure.parquet +Created by: parquet-mr version 1.14.3 (build b5e376a2caee767a11e75b783512b14cf8ca90ec) Review Comment: This is a released version. -- This is an automated message from the Apache Git Service. To respond to the message, please log on to GitHub and use the URL above to go to the specific comment. To unsubscribe, e-mail: [email protected] For queries about this service, please contact Infrastructure at: [email protected] --------------------------------------------------------------------- To unsubscribe, e-mail: [email protected] For additional commands, e-mail: [email protected]
