cdmikechen commented on code in PR #3391: URL: https://github.com/apache/hudi/pull/3391#discussion_r895724346
########## hudi-hadoop-mr/src/main/java/org/apache/hudi/hadoop/avro/HoodieAvroParquetReader.java: ########## @@ -0,0 +1,104 @@ +/* + * 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.hudi.hadoop.avro; + +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.io.ArrayWritable; +import org.apache.hadoop.mapreduce.InputSplit; +import org.apache.hadoop.mapreduce.RecordReader; +import org.apache.hadoop.mapreduce.TaskAttemptContext; +import org.apache.hudi.hadoop.HoodieColumnProjectionUtils; +import org.apache.hudi.hadoop.utils.HoodieRealtimeRecordReaderUtils; +import org.apache.parquet.avro.AvroReadSupport; +import org.apache.parquet.avro.AvroSchemaConverter; +import org.apache.parquet.format.converter.ParquetMetadataConverter; +import org.apache.parquet.hadoop.ParquetFileReader; +import org.apache.parquet.hadoop.ParquetInputSplit; +import org.apache.parquet.hadoop.ParquetRecordReader; +import org.apache.parquet.hadoop.metadata.ParquetMetadata; +import org.apache.parquet.schema.MessageType; + +import java.io.IOException; +import java.util.Arrays; +import java.util.List; +import java.util.stream.Collectors; + +import static org.apache.parquet.hadoop.ParquetInputFormat.getFilter; + +public class HoodieAvroParquetReader extends RecordReader<Void, ArrayWritable> { + + private final ParquetRecordReader<GenericData.Record> parquetRecordReader; + + public HoodieAvroParquetReader(InputSplit inputSplit, Configuration conf) throws IOException { + AvroReadSupport avroReadSupport = new AvroReadSupport<>(); + // if exists read columns, we need to filter columns. + List<String> readColNames = Arrays.asList(HoodieColumnProjectionUtils.getReadColumnNames(conf)); + if (!readColNames.isEmpty()) { + // get base schema + ParquetMetadata fileFooter = Review Comment: @codope Hi~. Your consideration is consistent with my original idea. This condition only occurs when there are query columns. Based on the `parquet-avro` methods, if there is a read schema, we need to manually specify the schema of the relevant fields to correctly output data. Otherwise, schema reading will wrong, I found this problem when I checked the test exception of Ci, and then I did this. https://github.com/apache/parquet-mr/blob/a89df8f9932b6ef6633d06069e50c9b7970bebd1/parquet-avro/src/main/java/org/apache/parquet/avro/AvroReadSupport.java#L86-L139 ```java @Override public ReadContext init(Configuration configuration, Map<String, String> keyValueMetaData, MessageType fileSchema) { MessageType projection = fileSchema; Map<String, String> metadata = new LinkedHashMap<String, String>(); String requestedProjectionString = configuration.get(AVRO_REQUESTED_PROJECTION); if (requestedProjectionString != null) { Schema avroRequestedProjection = new Schema.Parser().parse(requestedProjectionString); projection = new AvroSchemaConverter(configuration).convert(avroRequestedProjection); } String avroReadSchema = configuration.get(AVRO_READ_SCHEMA); if (avroReadSchema != null) { metadata.put(AVRO_READ_SCHEMA_METADATA_KEY, avroReadSchema); } if (configuration.getBoolean(AVRO_COMPATIBILITY, AVRO_DEFAULT_COMPATIBILITY)) { metadata.put(AVRO_COMPATIBILITY, "true"); } return new ReadContext(projection, metadata); } @Override public RecordMaterializer<T> prepareForRead( Configuration configuration, Map<String, String> keyValueMetaData, MessageType fileSchema, ReadContext readContext) { Map<String, String> metadata = readContext.getReadSupportMetadata(); MessageType parquetSchema = readContext.getRequestedSchema(); Schema avroSchema; if (metadata.get(AVRO_READ_SCHEMA_METADATA_KEY) != null) { // use the Avro read schema provided by the user avroSchema = new Schema.Parser().parse(metadata.get(AVRO_READ_SCHEMA_METADATA_KEY)); } else if (keyValueMetaData.get(AVRO_SCHEMA_METADATA_KEY) != null) { // use the Avro schema from the file metadata if present avroSchema = new Schema.Parser().parse(keyValueMetaData.get(AVRO_SCHEMA_METADATA_KEY)); } else if (keyValueMetaData.get(OLD_AVRO_SCHEMA_METADATA_KEY) != null) { // use the Avro schema from the file metadata if present avroSchema = new Schema.Parser().parse(keyValueMetaData.get(OLD_AVRO_SCHEMA_METADATA_KEY)); } else { // default to converting the Parquet schema into an Avro schema avroSchema = new AvroSchemaConverter(configuration).convert(parquetSchema); } GenericData model = getDataModel(configuration); String compatEnabled = metadata.get(AvroReadSupport.AVRO_COMPATIBILITY); if (compatEnabled != null && Boolean.valueOf(compatEnabled)) { return newCompatMaterializer(parquetSchema, avroSchema, model); } return new AvroRecordMaterializer<T>(parquetSchema, avroSchema, model); } ``` -- This is an automated message from the Apache Git Service. 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