/**
* 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.hadoop.hive.ql.exec.persistence;
import java.io.File;
import java.io.FileInputStream;
import java.io.FileOutputStream;
import java.io.IOException;
import org.apache.hadoop.fs.FileUtil;
import org.apache.hadoop.hive.common.FileUtils;
import org.apache.hadoop.hive.ql.exec.SerializationUtilities;
import org.apache.hadoop.hive.ql.metadata.HiveException;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import com.esotericsoftware.kryo.Kryo;
import com.esotericsoftware.kryo.io.Input;
import com.esotericsoftware.kryo.io.Output;
import com.google.common.annotations.VisibleForTesting;
import com.google.common.base.Preconditions;
/**
* An eager object container that puts every row directly to output stream.
* The object can be of any type.
* Kryo is used for the serialization/deserialization.
* When reading, we load IN_MEMORY_NUM_ROWS rows from input stream to memory batch by batch.
*/
@SuppressWarnings("unchecked")
public class ObjectContainer<ROW> {
private static final Logger LOG = LoggerFactory.getLogger(ObjectContainer.class);
@VisibleForTesting
static final int IN_MEMORY_NUM_ROWS = 1024;
private ROW[] readBuffer;
private boolean readBufferUsed = false; // indicates if read buffer has data
private int rowsInReadBuffer = 0; // number of rows in the temporary read buffer
private int readCursor = 0; // cursor during reading
private int rowsOnDisk = 0; // total number of objects in output
private File parentDir;
private File tmpFile;
private Input input;
private Output output;
public ObjectContainer(String spillLocalDirs) {
readBuffer = (ROW[]) new Object[IN_MEMORY_NUM_ROWS];
for (int i = 0; i < IN_MEMORY_NUM_ROWS; i++) {
readBuffer[i] = (ROW) new Object();
}
try {
setupOutput(spillLocalDirs);
} catch (IOException | HiveException e) {
throw new RuntimeException("Failed to create temporary output file on disk", e);
}
}
private void setupOutput(String spillLocalDirs) throws IOException, HiveException {
FileOutputStream fos = null;
try {
if (parentDir == null) {
parentDir = FileUtils.createLocalDirsTempFile(spillLocalDirs, "object-container", "", true);
}
if (tmpFile == null || input != null) {
tmpFile = File.createTempFile("ObjectContainer", ".tmp", parentDir);
LOG.info("ObjectContainer created temp file " + tmpFile.getAbsolutePath());
tmpFile.deleteOnExit();
}
fos = new FileOutputStream(tmpFile);
output = new Output(fos);
} catch (IOException e) {
throw new HiveException(e);
} finally {
if (output == null && fos != null) {
fos.close();
}
}
}
public void add(ROW row) {
Kryo kryo = SerializationUtilities.borrowKryo();
try {
kryo.writeClassAndObject(output, row);
} finally {
SerializationUtilities.releaseKryo(kryo);
}
rowsOnDisk++;
}
public void clear() {
readCursor = rowsInReadBuffer = rowsOnDisk = 0;
readBufferUsed = false;
if (parentDir != null) {
if (input != null) {
try {
input.close();
} catch (Throwable ignored) {
}
input = null;
}
if (output != null) {
try {
output.close();
} catch (Throwable ignored) {
}
output = null;
}
try {
FileUtil.fullyDelete(parentDir);
} catch (Throwable ignored) {
}
parentDir = null;
tmpFile = null;
}
}
public boolean hasNext() {
return readBufferUsed || rowsOnDisk > 0;
}
public ROW next() {
Preconditions.checkState(hasNext());
if (!readBufferUsed) {
try {
if (input == null && output != null) {
// Close output stream if open
output.close();
output = null;
FileInputStream fis = null;
try {
fis = new FileInputStream(tmpFile);
input = new Input(fis);
} finally {
if (input == null && fis != null) {
fis.close();
}
}
}
if (input != null) {
// Load next batch from disk
if (rowsOnDisk >= IN_MEMORY_NUM_ROWS) {
rowsInReadBuffer = IN_MEMORY_NUM_ROWS;
} else {
rowsInReadBuffer = rowsOnDisk;
}
Kryo kryo = SerializationUtilities.borrowKryo();
try {
for (int i = 0; i < rowsInReadBuffer; i++) {
readBuffer[i] = (ROW) kryo.readClassAndObject(input);
}
} finally {
SerializationUtilities.releaseKryo(kryo);
}
if (input.eof()) {
input.close();
input = null;
}
readBufferUsed = true;
readCursor = 0;
rowsOnDisk -= rowsInReadBuffer;
}
} catch (Exception e) {
clear(); // Clean up the cache
throw new RuntimeException("Failed to load rows from disk", e);
}
}
ROW row = readBuffer[readCursor];
if (++readCursor >= rowsInReadBuffer) {
readBufferUsed = false;
rowsInReadBuffer = 0;
readCursor = 0;
}
return row;
}
public int size() {
return rowsInReadBuffer + rowsOnDisk;
}
}