[GitHub] [flink] bowenli86 commented on a change in pull request #8522: [FLINK-12572][hive]Implement HiveInputFormat to read Hive tables

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bowenli86 commented on a change in pull request #8522: [FLINK-12572][hive]Implement HiveInputFormat to read Hive tables
URL: https://github.com/apache/flink/pull/8522#discussion_r289952273
 
 

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 File path: flink-connectors/flink-connector-hive/src/main/java/org/apache/flink/batch/connectors/hive/HiveTableInputFormat.java
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+/*
+ * 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.batch.connectors.hive;
+
+import org.apache.flink.api.common.io.LocatableInputSplitAssigner;
+import org.apache.flink.api.common.io.statistics.BaseStatistics;
+import org.apache.flink.api.common.typeinfo.TypeInformation;
+import org.apache.flink.api.java.hadoop.common.HadoopInputFormatCommonBase;
+import org.apache.flink.api.java.hadoop.mapred.wrapper.HadoopDummyReporter;
+import org.apache.flink.api.java.typeutils.ResultTypeQueryable;
+import org.apache.flink.core.fs.FileStatus;
+import org.apache.flink.core.io.InputSplitAssigner;
+import org.apache.flink.table.catalog.hive.util.HiveTableUtil;
+import org.apache.flink.table.dataformat.BaseRow;
+import org.apache.flink.table.dataformat.GenericRow;
+import org.apache.flink.table.typeutils.BaseRowTypeInfo;
+
+import org.apache.hadoop.conf.Configurable;
+import org.apache.hadoop.conf.Configuration;
+import org.apache.hadoop.hive.metastore.api.StorageDescriptor;
+import org.apache.hadoop.hive.serde2.Deserializer;
+import org.apache.hadoop.hive.serde2.SerDeUtils;
+import org.apache.hadoop.hive.serde2.objectinspector.StructField;
+import org.apache.hadoop.hive.serde2.objectinspector.StructObjectInspector;
+import org.apache.hadoop.io.Writable;
+import org.apache.hadoop.mapred.FileInputFormat;
+import org.apache.hadoop.mapred.InputFormat;
+import org.apache.hadoop.mapred.JobConf;
+import org.apache.hadoop.mapred.JobConfigurable;
+import org.apache.hadoop.mapred.RecordReader;
+import org.apache.hadoop.security.Credentials;
+import org.apache.hadoop.security.UserGroupInformation;
+import org.apache.hadoop.util.ReflectionUtils;
+import org.slf4j.Logger;
+import org.slf4j.LoggerFactory;
+
+import java.io.IOException;
+import java.io.ObjectInputStream;
+import java.io.ObjectOutputStream;
+import java.util.ArrayList;
+import java.util.List;
+import java.util.Properties;
+
+import static org.apache.hadoop.mapreduce.lib.input.FileInputFormat.INPUT_DIR;
+
+/**
+ * The HiveTableInputFormat are inspired by the HCatInputFormat and HadoopInputFormatBase.
+ */
+public class HiveTableInputFormat extends HadoopInputFormatCommonBase<BaseRow, HiveTableInputSplit>
+		implements ResultTypeQueryable {
+	private static final long serialVersionUID = 6351448428766433164L;
+	private static Logger logger = LoggerFactory.getLogger(HiveTableInputFormat.class);
+
+	private JobConf jobConf;
+
+	protected transient Writable key;
+	protected transient Writable value;
+
+	private transient RecordReader<Writable, Writable> recordReader;
+	protected transient boolean fetched = false;
+	protected transient boolean hasNext;
+
+	private Boolean isPartitioned;
+	private BaseRowTypeInfo baseRowTypeInfo;
+
+	// Necessary info to init deserializer
+	private String[] partitionColNames;
+	private List<HiveTablePartition> partitions;
+	private transient Deserializer deserializer;
+	private transient List<? extends StructField> fieldRefs;
+	private transient StructObjectInspector oi;
+	private transient InputFormat mapredInputFormat;
+	private transient HiveTablePartition hiveTablePartition;
+
+	public HiveTableInputFormat(
+			JobConf jobConf,
+			Boolean isPartitioned,
+			String[] partitionColNames,
+			List<HiveTablePartition> partitions,
+			BaseRowTypeInfo baseRowTypeInfo) {
+		super(jobConf.getCredentials());
+		this.baseRowTypeInfo = baseRowTypeInfo;
+		this.jobConf = new JobConf(jobConf);
+		this.jobConf = jobConf;
+		this.isPartitioned = isPartitioned;
+		this.partitionColNames = partitionColNames;
+		this.partitions = partitions;
+	}
+
+	@Override
+	public void open(HiveTableInputSplit split) throws IOException {
+		this.hiveTablePartition = split.getHiveTablePartition();
+		StorageDescriptor sd = hiveTablePartition.getStorageDescriptor();
+		jobConf.set(INPUT_DIR, sd.getLocation());
+		try {
+			this.mapredInputFormat = (InputFormat)
+				Class.forName(sd.getInputFormat(), true, Thread.currentThread().getContextClassLoader()).newInstance();
+		} catch (Exception e) {
+			throw new RuntimeException("Unable to instantiate the hadoop input format", e);
+		}
+		ReflectionUtils.setConf(mapredInputFormat, jobConf);
+		if (this.mapredInputFormat instanceof Configurable) {
+			((Configurable) this.mapredInputFormat).setConf(this.jobConf);
+		} else if (this.mapredInputFormat instanceof JobConfigurable) {
+			((JobConfigurable) this.mapredInputFormat).configure(this.jobConf);
+		}
+		this.recordReader = this.mapredInputFormat.getRecordReader(split.getHadoopInputSplit(),
+			jobConf, new HadoopDummyReporter());
+		if (this.recordReader instanceof Configurable) {
+			((Configurable) this.recordReader).setConf(jobConf);
+		}
+		key = this.recordReader.createKey();
+		value = this.recordReader.createValue();
+		this.fetched = false;
+		try {
+			deserializer = (Deserializer) Class.forName(sd.getSerdeInfo().getSerializationLib()).newInstance();
+			Configuration conf = new Configuration();
+			Properties properties = HiveTableUtil.createPropertiesFromStorageDescriptor(sd);
+			SerDeUtils.initializeSerDe(deserializer, conf, properties, null);
+			// Get the row structure
+			oi = (StructObjectInspector) deserializer.getObjectInspector();
+			fieldRefs = oi.getAllStructFieldRefs();
+		} catch (Exception e) {
+			logger.error("Error happens when deserialize from storage file.");
+			throw new RuntimeException(e);
+		}
+	}
+
+	@Override
+	public HiveTableInputSplit[] createInputSplits(int minNumSplits)
+			throws IOException {
+		List<HiveTableInputSplit> hiSplit = new ArrayList<>();
+		int splitNum = 0;
+		for (HiveTablePartition partition : partitions) {
+			StorageDescriptor sd = partition.getStorageDescriptor();
+			InputFormat format;
+			try {
+				format = (InputFormat)
+					Class.forName(sd.getInputFormat(), true, Thread.currentThread().getContextClassLoader()).newInstance();
+			} catch (Exception e) {
+				throw new RuntimeException("Unable to instantiate the hadoop input format", e);
+			}
+			ReflectionUtils.setConf(format, jobConf);
+			jobConf.set(INPUT_DIR, sd.getLocation());
+			//TODO: we should consider how to calculate the splits according to minNumSplits in the future.
+			org.apache.hadoop.mapred.InputSplit[] splitArray = format.getSplits(jobConf, minNumSplits);
+			for (int i = 0; i < splitArray.length; i++) {
+				hiSplit.add(new HiveTableInputSplit(splitNum++, splitArray[i], jobConf, partition));
+			}
+		}
+
+		return hiSplit.toArray(new HiveTableInputSplit[hiSplit.size()]);
+	}
+
+	@Override
+	public void configure(org.apache.flink.configuration.Configuration parameters) {
+
+	}
+
+	// Todo: refactor code to get statistics from hms or partition.
+	@Override
+	public BaseStatistics getStatistics(BaseStatistics cachedStats) throws IOException {
+		// only gather base statistics for FileInputFormats
+		if (!(mapredInputFormat instanceof FileInputFormat)) {
+			return null;
+		}
+
+		final org.apache.flink.api.common.io.FileInputFormat.FileBaseStatistics cachedFileStats =
+				(cachedStats instanceof org.apache.flink.api.common.io.FileInputFormat.FileBaseStatistics) ?
+				(org.apache.flink.api.common.io.FileInputFormat.FileBaseStatistics) cachedStats : null;
+
+		try {
+			final org.apache.hadoop.fs.Path[] paths = FileInputFormat.getInputPaths(this.jobConf);
+
+			return HiveTableUtil.getFileStats(cachedFileStats, paths, new ArrayList<FileStatus>(1));
+		} catch (IOException ioex) {
+			if (logger.isWarnEnabled()) {
+				logger.warn("Could not determine statistics due to an io error: "
+							+ ioex.getMessage());
+			}
+		} catch (Throwable t) {
+			if (logger.isErrorEnabled()) {
+				logger.error("Unexpected problem while getting the file statistics: " + t.getMessage(), t);
+			}
+		}
+
+		// no statistics available
+		return null;
+	}
+
+	@Override
+	public InputSplitAssigner getInputSplitAssigner(HiveTableInputSplit[] inputSplits) {
+		return new LocatableInputSplitAssigner(inputSplits);
+	}
+
+	@Override
+	public boolean reachedEnd() throws IOException {
+		if (!fetched) {
 
 Review comment:
   ok, I read the `HCatInputFormatBase` and `HadoopInputFormatBase`, and yes, they are implemented this way.

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