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https://issues.apache.org/jira/browse/FLINK-7243?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=16645671#comment-16645671
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ASF GitHub Bot commented on FLINK-7243:
---------------------------------------
fhueske 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_r224248653
##########
File path:
flink-formats/flink-parquet/src/main/java/org/apache/flink/formats/parquet/ParquetInputFormat.java
##########
@@ -0,0 +1,241 @@
+/*
+ * 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;
+
+import org.apache.flink.api.common.io.CheckpointableInputFormat;
+import org.apache.flink.api.common.io.FileInputFormat;
+import org.apache.flink.api.common.typeinfo.TypeInformation;
+import org.apache.flink.api.java.tuple.Tuple2;
+import org.apache.flink.api.java.typeutils.RowTypeInfo;
+import org.apache.flink.core.fs.FileInputSplit;
+import org.apache.flink.core.fs.Path;
+import org.apache.flink.formats.parquet.utils.ParquetRecordReader;
+import org.apache.flink.formats.parquet.utils.ParquetSchemaConverter;
+import org.apache.flink.formats.parquet.utils.RowReadSupport;
+import org.apache.flink.metrics.Counter;
+import org.apache.flink.types.Row;
+import org.apache.flink.util.Preconditions;
+
+import org.apache.parquet.ParquetReadOptions;
+import org.apache.parquet.filter2.compat.FilterCompat;
+import org.apache.parquet.hadoop.ParquetFileReader;
+import org.apache.parquet.hadoop.util.HadoopInputFile;
+import org.apache.parquet.io.InputFile;
+import org.apache.parquet.schema.MessageType;
+import org.apache.parquet.schema.Type;
+import org.slf4j.Logger;
+import org.slf4j.LoggerFactory;
+
+import java.io.IOException;
+import java.util.ArrayList;
+import java.util.List;
+
+/**
+ * The base InputFormat class to read from Parquet files.
+ * For specific return types the {@link #convert(Row)} method need to be
implemented.
+ *
+ * <P>Using {@link ParquetRecordReader} to read files instead of {@link
org.apache.flink.core.fs.FSDataInputStream},
+ * we override {@link #open(FileInputSplit)} and {@link #close()} to change
the behaviors.
+ *
+ * @param <E> The type of record to read.
+ */
+public abstract class ParquetInputFormat<E>
+ extends FileInputFormat<E>
+ implements CheckpointableInputFormat<FileInputSplit, Tuple2<Long,
Long>> {
+
+ private static final long serialVersionUID = 1L;
+
+ private static final Logger LOG =
LoggerFactory.getLogger(ParquetInputFormat.class);
+
+ private transient Counter recordConsumed;
+
+ private final TypeInformation[] fieldTypes;
+
+ private final String[] fieldNames;
+
+ private boolean skipThisSplit = false;
+
+ private transient ParquetRecordReader<Row> parquetRecordReader;
+
+ private transient long recordsReadSinceLastSync;
+
+ private long lastSyncedBlock = -1L;
+
+ /**
+ * Read parquet files with given result parquet schema.
+ *
+ * @param path The path of the file to read.
+ * @param messageType schema of read result
+ */
+
+ protected ParquetInputFormat(Path path, MessageType messageType) {
+ super(path);
+ RowTypeInfo readType = (RowTypeInfo)
ParquetSchemaConverter.fromParquetType(messageType);
+ this.fieldTypes = readType.getFieldTypes();
+ this.fieldNames = readType.getFieldNames();
+ // read whole parquet file as one file split
+ this.unsplittable = true;
+ }
+
+ /**
+ * Read parquet files with given result field names and types.
+ *
+ * @param path The path of the file to read.
+ * @param fieldTypes field types of read result of fields
+ * @param fieldNames field names to read, which can be subset of the
parquet schema
+ */
+ protected ParquetInputFormat(Path path, TypeInformation[] fieldTypes,
String[] fieldNames) {
+ super(path);
+ this.fieldTypes = fieldTypes;
+ this.fieldNames = fieldNames;
+ // read whole parquet file as one file split
+ this.unsplittable = true;
+ }
+
+ @Override
+ public Tuple2<Long, Long> getCurrentState() {
+ return new Tuple2<>(this.lastSyncedBlock,
this.recordsReadSinceLastSync);
+ }
+
+ @Override
+ public void open(FileInputSplit split) throws IOException {
+ org.apache.hadoop.conf.Configuration configuration = new
org.apache.hadoop.conf.Configuration();
+ InputFile inputFile =
+ HadoopInputFile.fromPath(new
org.apache.hadoop.fs.Path(split.getPath().toUri()), configuration);
+ ParquetReadOptions options =
ParquetReadOptions.builder().build();
+ ParquetFileReader fileReader = new ParquetFileReader(inputFile,
options);
+ MessageType schema = fileReader.getFileMetaData().getSchema();
+ this.skipThisSplit = false;
+ MessageType readSchema = getReadSchema(schema);
+ this.parquetRecordReader = new ParquetRecordReader<>(new
RowReadSupport(), readSchema, FilterCompat.NOOP);
Review comment:
Wouldn't it make more sense to have different `ReadSupport` implementations
for the different target types (Map, Pojo, Row), instead of always reading as
`Row` and from there converting to the other types?
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> Add ParquetInputFormat
> ----------------------
>
> Key: FLINK-7243
> URL: https://issues.apache.org/jira/browse/FLINK-7243
> Project: Flink
> Issue Type: Sub-task
> Components: Table API & SQL
> Reporter: godfrey he
> Assignee: Zhenqiu Huang
> Priority: Major
> Labels: pull-request-available
>
> Add a {{ParquetInputFormat}} to read data from a Apache Parquet file.
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