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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.hadoop.hive.ql.exec.spark;
import java.io.File;
import java.io.FileInputStream;
import java.io.FileOutputStream;
import java.io.IOException;
import org.apache.commons.logging.Log;
import org.apache.commons.logging.LogFactory;
import org.apache.hadoop.fs.FileUtil;
import org.apache.hadoop.hive.common.ObjectPair;
import org.apache.hadoop.hive.ql.io.HiveKey;
import org.apache.hadoop.io.BytesWritable;
import scala.Tuple2;
import com.esotericsoftware.kryo.io.Input;
import com.esotericsoftware.kryo.io.Output;
import com.google.common.annotations.VisibleForTesting;
import com.google.common.base.Preconditions;
/**
* A cache with fixed buffer. If the buffer is full, new entries will
* be written to disk. This class is thread safe since multiple threads
* could access it (doesn't have to be concurrently), for example,
* the StreamThread in ScriptOperator.
*/
@SuppressWarnings("unchecked")
class HiveKVResultCache {
private static final Log LOG = LogFactory.getLog(HiveKVResultCache.class);
@VisibleForTesting
static final int IN_MEMORY_NUM_ROWS = 1024;
private ObjectPair[] writeBuffer;
private ObjectPair[] readBuffer;
private File parentFile;
private File tmpFile;
private int readCursor = 0;
private int writeCursor = 0;
// Indicate if the read buffer has data, for example,
// when in reading, data on disk could be pull in
private boolean readBufferUsed = false;
private int rowsInReadBuffer = 0;
private Input input;
private Output output;
public HiveKVResultCache() {
writeBuffer = new ObjectPair[IN_MEMORY_NUM_ROWS];
readBuffer = new ObjectPair[IN_MEMORY_NUM_ROWS];
for (int i = 0; i < IN_MEMORY_NUM_ROWS; i++) {
writeBuffer[i] = new ObjectPair();
readBuffer[i] = new ObjectPair();
}
}
private void switchBufferAndResetCursor() {
ObjectPair[] tmp = readBuffer;
rowsInReadBuffer = writeCursor;
readBuffer = writeBuffer;
readBufferUsed = true;
readCursor = 0;
writeBuffer = tmp;
writeCursor = 0;
}
private void setupOutput() throws IOException {
if (parentFile == null) {
while (true) {
parentFile = File.createTempFile("hive-resultcache", "");
if (parentFile.delete() && parentFile.mkdir()) {
parentFile.deleteOnExit();
break;
}
if (LOG.isDebugEnabled()) {
LOG.debug("Retry creating tmp result-cache directory...");
}
}
}
if (tmpFile == null || input != null) {
tmpFile = File.createTempFile("ResultCache", ".tmp", parentFile);
LOG.info("ResultCache created temp file " + tmpFile.getAbsolutePath());
tmpFile.deleteOnExit();
}
FileOutputStream fos = null;
try {
fos = new FileOutputStream(tmpFile);
output = new Output(fos);
} finally {
if (output == null && fos != null) {
fos.close();
}
}
}
private BytesWritable readValue(Input input) {
return new BytesWritable(input.readBytes(input.readInt()));
}
private void writeValue(Output output, BytesWritable bytesWritable) {
int size = bytesWritable.getLength();
output.writeInt(size);
output.writeBytes(bytesWritable.getBytes(), 0, size);
}
private HiveKey readHiveKey(Input input) {
HiveKey hiveKey = new HiveKey(
input.readBytes(input.readInt()), input.readInt());
hiveKey.setDistKeyLength(input.readInt());
return hiveKey;
}
private void writeHiveKey(Output output, HiveKey hiveKey) {
int size = hiveKey.getLength();
output.writeInt(size);
output.writeBytes(hiveKey.getBytes(), 0, size);
output.writeInt(hiveKey.hashCode());
output.writeInt(hiveKey.getDistKeyLength());
}
public synchronized void add(HiveKey key, BytesWritable value) {
if (writeCursor >= IN_MEMORY_NUM_ROWS) { // Write buffer is full
if (!readBufferUsed) { // Read buffer isn't used, switch buffer
switchBufferAndResetCursor();
} else {
// Need to spill from write buffer to disk
try {
if (output == null) {
setupOutput();
}
for (int i = 0; i < IN_MEMORY_NUM_ROWS; i++) {
ObjectPair pair = writeBuffer[i];
writeHiveKey(output, pair.getFirst());
writeValue(output, pair.getSecond());
pair.setFirst(null);
pair.setSecond(null);
}
writeCursor = 0;
} catch (Exception e) {
clear(); // Clean up the cache
throw new RuntimeException("Failed to spill rows to disk", e);
}
}
}
ObjectPair pair = writeBuffer[writeCursor++];
pair.setFirst(key);
pair.setSecond(value);
}
public synchronized void clear() {
writeCursor = readCursor = rowsInReadBuffer = 0;
readBufferUsed = false;
if (parentFile != 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(parentFile);
} catch (Throwable ignored) {
}
parentFile = null;
tmpFile = null;
}
}
public synchronized boolean hasNext() {
return readBufferUsed || writeCursor > 0;
}
public synchronized Tuple2 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
for (int i = 0; i < IN_MEMORY_NUM_ROWS; i++) {
ObjectPair pair = readBuffer[i];
pair.setFirst(readHiveKey(input));
pair.setSecond(readValue(input));
}
if (input.eof()) {
input.close();
input = null;
}
rowsInReadBuffer = IN_MEMORY_NUM_ROWS;
readBufferUsed = true;
readCursor = 0;
} else if (writeCursor == 1) {
ObjectPair pair = writeBuffer[0];
Tuple2 row = new Tuple2(
pair.getFirst(), pair.getSecond());
pair.setFirst(null);
pair.setSecond(null);
writeCursor = 0;
return row;
} else {
// No record on disk, more data in write buffer
switchBufferAndResetCursor();
}
} catch (Exception e) {
clear(); // Clean up the cache
throw new RuntimeException("Failed to load rows from disk", e);
}
}
ObjectPair pair = readBuffer[readCursor];
Tuple2 row = new Tuple2(
pair.getFirst(), pair.getSecond());
pair.setFirst(null);
pair.setSecond(null);
if (++readCursor >= rowsInReadBuffer) {
readBufferUsed = false;
rowsInReadBuffer = 0;
readCursor = 0;
}
return row;
}
}
