Hi all.
I have a mapreduce program with two jobs. second job's key and value comes
from first job output. but I think the second map does not get the result
from first job. in other words I think my second job did not read the
output of my first job.. what should I do?
here is the code:
public class dewpoint extends Configured implements Tool
{
private static final Logger logger = LoggerFactory.getLogger(dewpoint.class);
static final String KEYSPACE = "weather";
static final String COLUMN_FAMILY = "user";
private static final String OUTPUT_PATH1 = "/tmp/intermediate1";
private static final String OUTPUT_PATH2 = "/tmp/intermediate2";
private static final String OUTPUT_PATH3 = "/tmp/intermediate3";
private static final String INPUT_PATH1 = "/tmp/intermediate1";
public static void main(String[] args) throws Exception
{
ToolRunner.run(new Configuration(), new dewpoint(), args);
System.exit(0);
}
///////////////////////////////////////////////////////////
public static class dpmap1 extends Mapper<Map<String, ByteBuffer>,
Map<FloatWritable, ByteBuffer>, Text, DoubleWritable>
{
DoubleWritable val1 = new DoubleWritable();
Text word = new Text();
String date;
float temp;
public void map(Map<String, ByteBuffer> keys, Map<FloatWritable,
ByteBuffer> columns, Context context) throws IOException,
InterruptedException
{
for (Entry<String, ByteBuffer> key : keys.entrySet())
{
//System.out.println(key.getKey());
if (!"date".equals(key.getKey()))
continue;
date = ByteBufferUtil.string(key.getValue());
word.set(date);
}
for (Entry<FloatWritable, ByteBuffer> column : columns.entrySet())
{
if (!"temprature".equals(column.getKey()))
continue;
temp = ByteBufferUtil.toFloat(column.getValue());
val1.set(temp);
//System.out.println(temp);
}
context.write(word, val1);
}
}
///////////////////////////////////////////////////////////
public static class dpred1 extends Reducer<Text, DoubleWritable, Text,
DoubleWritable>
{
public void reduce(Text key, Iterable<DoubleWritable> values,
Context context) throws IOException, InterruptedException
{
double beta = 17.62;
double landa = 243.12;
DoubleWritable result1 = new DoubleWritable();
DoubleWritable result2 = new DoubleWritable();
for (DoubleWritable val : values){
// System.out.println(val.get());
beta *= val.get();
landa+=val.get();
}
result1.set(beta);
result2.set(landa);
context.write(key, result1);
context.write(key, result2);
}
}
///////////////////////////////////////////////////////////
public static class dpmap2 extends Mapper <Text, DoubleWritable, Text,
DoubleWritable>{
Text key2 = new Text();
double temp1, temp2 =0;
public void map(Text key, Iterable<DoubleWritable> values, Context
context) throws IOException, InterruptedException {
String[] sp = values.toString().split("\t");
for (int i=0; i< sp.length; i+=4)
//key2.set(sp[i]);
System.out.println(sp[i]);
for(int j=1;j< sp.length; j+=4)
temp1 = Double.valueOf(sp[j]);
for (int k=3;k< sp.length; k+=4)
temp2 = Double.valueOf(sp[k]);
context.write(key2, new DoubleWritable(temp2/temp1));
}
}
///////////////////////////////////////////////////////////
public static class dpred2 extends Reducer<Text, DoubleWritable, Text,
DoubleWritable>
{
public void reduce(Text key, Iterable<DoubleWritable> values,
Context context) throws IOException, InterruptedException
{
double alpha = 6.112;
double tmp = 0;
DoubleWritable result3 = new DoubleWritable();
for (DoubleWritable val : values){
System.out.println(val.get());
tmp = alpha*(Math.pow(Math.E, val.get()));
}
result3.set(tmp);
context.write(key, result3);
}
}
///////////////////////////////////////////////////////////
public int run(String[] args) throws Exception
{
Job job1 = new Job(getConf(), "DewPoint");
job1.setJarByClass(dewpoint.class);
job1.setMapperClass(dpmap1.class);
job1.setOutputFormatClass(SequenceFileOutputFormat.class);
job1.setCombinerClass(dpred1.class);
job1.setReducerClass(dpred1.class);
job1.setMapOutputKeyClass(Text.class);
job1.setMapOutputValueClass(DoubleWritable.class);
job1.setOutputKeyClass(Text.class);
job1.setOutputValueClass(DoubleWritable.class);
FileOutputFormat.setOutputPath(job1, new Path(OUTPUT_PATH1));
job1.setInputFormatClass(CqlPagingInputFormat.class);
ConfigHelper.setInputRpcPort(job1.getConfiguration(), "9160");
ConfigHelper.setInputInitialAddress(job1.getConfiguration(), "localhost");
ConfigHelper.setInputColumnFamily(job1.getConfiguration(),
KEYSPACE, COLUMN_FAMILY);
ConfigHelper.setInputPartitioner(job1.getConfiguration(),
"Murmur3Partitioner");
CqlConfigHelper.setInputCQLPageRowSize(job1.getConfiguration(), "3");
job1.waitForCompletion(true);
/***************************************/
if (job1.isSuccessful()){
Job job2 = new Job(getConf(), "DewPoint");
job2.setJarByClass(dewpoint.class);
job2.setMapperClass(dpmap2.class);
job2.setCombinerClass(dpred2.class);
job2.setReducerClass(dpred2.class);
job2.setMapOutputKeyClass(Text.class);
job2.setMapOutputValueClass(DoubleWritable.class);
job2.setOutputKeyClass(Text.class);
job2.setOutputValueClass(DoubleWritable.class);
job2.setOutputFormatClass(TextOutputFormat.class);
job2.setInputFormatClass(SequenceFileInputFormat.class);
FileInputFormat.addInputPath(job2, new Path(OUTPUT_PATH1));
FileOutputFormat.setOutputPath(job2, new Path(OUTPUT_PATH2));
job2.waitForCompletion(true);
}
///////////////////////////////////////////////////
return 0;
}
}
for example in my second map phase when I do a System.out.println(key)
it does not print any thing and in reduce result the value is
'infinity'....
