Multi-Thread Job in Hadoop 實驗

問題定義
假設今有2 Jobs, 皆讀取相同格式之資料,但是每個Job 處理的方式與輸出資料皆不相同。
Job 1: Source Data A→ Map → Reduce → Output B
Job 2: Source Data A→ Map → Reduce → Output C
若今天以Job1 → Job 2的順序,分別需要 20 seconds, 30 seconds則總時間需要 50 seconds是否能夠平行處理的技巧,達到Performance的提升?
目標與方法
利用Multithreads Job1Job2 同時進行。期望透過平行處理的方式,讓工作能夠在30~50秒內做完,提升處理速度。
實驗設計與數據呈現
硬體環境:
伺服器2台:cloud1, cloud2
伺服器硬體配置:
CPU: 雙路AMD 雙核心
記憶體:8GB
硬碟:1TB 7200 rpm.
軟體與資料環境:
Hadoop 0.20.xmaster nodecloud1slave nodecloud1cloud2
MySQL Database運行在cloud2
實驗設計:
設計兩個JobJob1Job2Job1的工作流程:
資料來源1 → WordCount ( MapReduce) →以資料格式1 輸出到MySQL Server
資料來源1 → WordCount ( MapReduce) →以資料格式2輸出到MySQL Server
注意!會區分資料格式1與資料格式2是因為Job1Job2輸出的內容不太一樣。
資料集:自己產生之資料集,大小為556 KB

數據呈現:
Job1執行時間()
Job2執行時間()
總執行時間
Job1Job2循序執行
21
21
42
Job1Job2採多執行緒執行
21
21
21

結論
以上述小型測試發現,Multi-Thread Job in Hadoop或許是一個不錯的並行加速方案。




程式碼

import java.io.IOException;
import java.util.*;

import org.apache.hadoop.fs.Path;
import org.apache.hadoop.conf.*;
import org.apache.hadoop.io.*;
import org.apache.hadoop.io.Writable;
import org.apache.hadoop.mapred.*;
import org.apache.hadoop.util.*;
import java.io.DataInput;
import java.io.DataOutput;
import java.lang.Thread;
import java.sql.PreparedStatement;
import java.sql.ResultSet;
import java.sql.SQLException;
import org.apache.hadoop.mapred.lib.db.DBWritable;
import org.apache.hadoop.mapred.lib.IdentityReducer;
import org.apache.hadoop.mapred.lib.db.DBConfiguration;
import org.apache.hadoop.mapred.lib.db.DBOutputFormat;
import org.apache.hadoop.mapred.lib.db.DBInputFormat;
/*
MySQL DB Schema:

DROP TABLE IF EXISTS `WordCount`.`Counting`;
CREATE TABLE `WordCount`.`Counting` (
`name` char(48) default NULL,
`count` int(11) default NULL
) ENGINE=InnoDB DEFAULT CHARSET=latin1;

*/

public class DBWordCount extends Thread
{
public void run() //throws Exception
{
/* Start ! */
try
{
JobClient.runJob(conf);
}
catch(Exception e)
{
// do nothing
}
}

public void fnSetJob1(String[] args) throws Exception
{
conf.setJobName("MySQL DB Wordcount Job1");


Class.forName("com.mysql.jdbc.Driver");

conf.setInputFormat(TextInputFormat.class);
conf.setOutputFormat(DBOutputFormat.class);
FileInputFormat.setInputPaths(conf, new Path(args[0]));

// Set up your host name and account
String[] MyDBPath={"jdbc:mysql://MySQL主機位置:3306/WordCount","帳號", "密碼"};
DBConfiguration.configureDB(conf, "com.mysql.jdbc.Driver",MyDBPath[0], MyDBPath[1], MyDBPath[2]);

// Setup Output MySQL Format
DBOutputFormat.setOutput(conf, "Counting","name", "count");

// Set Mapper and Reducer Class
conf.setMapperClass(Map.class);
//conf.setCombinerClass(Reduce.class);
conf.setReducerClass(Reduce.class);

conf.setMapOutputKeyClass(Text.class);
conf.setMapOutputValueClass(IntWritable.class);
conf.setOutputKeyClass(WordCountInfoRecord.class);
conf.setOutputValueClass(NullWritable.class);
}

public void fnSetJob2(String[] args) throws Exception
{
//JobConf conf = new JobConf(DBWordCount.class);
conf.setJobName("MySQL DB Wordcount Job2");


Class.forName("com.mysql.jdbc.Driver");
// Set up your host name and account
String[] MyDBPath={"jdbc:mysql://MySQL主機位置:3306/WordCount","帳號", "密碼"};

conf.setInputFormat(TextInputFormat.class);
conf.setOutputFormat(DBOutputFormat.class);
FileInputFormat.setInputPaths(conf, new Path(args[0]));

// Setup MySQL Connection , default account:root , no password
DBConfiguration.configureDB(conf, "com.mysql.jdbc.Driver",MyDBPath[0], MyDBPath[1], MyDBPath[2]);

// Setup Output MySQL Format
DBOutputFormat.setOutput(conf, "Counting","name", "count");

// Set Mapper and Reducer Class
conf.setMapperClass(Map.class);
//conf.setCombinerClass(Reduce.class);
conf.setReducerClass(Reduce2.class);

// I've tried all combinations , but the bug still happen.
conf.setMapOutputKeyClass(Text.class);
conf.setMapOutputValueClass(IntWritable.class);
conf.setOutputKeyClass(WordCountInfoRecord.class);
conf.setOutputValueClass(NullWritable.class);
}

JobConf conf = new JobConf(DBWordCount.class);
//JobConf conf2 = new JobConf(DBWordCount.class);

// Output Record Object
static class WordCountInfoRecord implements Writable, DBWritable
{
public String name;
public int count;
public WordCountInfoRecord() {

}

public WordCountInfoRecord(String str, int c)
{
this.name = str;
this.count = c;
}

public void readFields(DataInput in) throws IOException {
this.name = Text.readString(in);
this.count = in.readInt();
}
public void write(DataOutput out) throws IOException {
Text.writeString(out, this.name);
out.writeInt(this.count);
}

public void readFields(ResultSet result) throws SQLException {
this.name = result.getString(1);
this.count = result.getInt(2);
}
public void write(PreparedStatement stmt) throws SQLException {
stmt.setString(1, this.name);
stmt.setInt(2, this.count);
}
public String toString() {
return new String(this.name + " " + this.count);
}
}

public static class Map extends MapReduceBase implements Mapper
{

private final static IntWritable one = new IntWritable(1);
private Text word = new Text();

public void map(LongWritable key, Text value, OutputCollector output, Reporter reporter) throws IOException
{
String line = value.toString();
StringTokenizer tokenizer = new StringTokenizer(line);
while (tokenizer.hasMoreTokens()) {
word.set(tokenizer.nextToken());
output.collect(word, one);
}
}
}


public static class Reduce extends MapReduceBase implements Reducer
{
public void reduce(Text key, Iterator values, OutputCollector output, Reporter reporter) throws IOException
{
int sum = 0;
while (values.hasNext()) {
sum += values.next().get();
}
// Output Data into MySQL
output.collect(new WordCountInfoRecord(key.toString(),sum), NullWritable.get());
}
}

public static class Reduce2 extends MapReduceBase implements Reducer
{
public void reduce(Text key, Iterator values, OutputCollector output, Reporter reporter) throws IOException
{
int sum = 0;
while (values.hasNext()) {
sum += values.next().get();
}
// Output Data into MySQL
output.collect(new WordCountInfoRecord("Job2_"+key.toString(),sum), NullWritable.get());
}
}

public static void main(String[] args) throws Exception
{
DBWordCount thread1=new DBWordCount();
// Set Thread1
thread1.fnSetJob1(args);
DBWordCount thread2=new DBWordCount();
// Set Thread2
thread2.fnSetJob2(args);
// Thread 1 Start
thread1.start();
// Thread 2 Start
thread2.start();

}
}
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