Hadoop Single Node Silent Freeze

Hadoop Single Node Silent Freeze

I have a MapReduce tool that freezes on the first mapper with no
discernible output. Because this is a single node installation, I have not
been able to access the job tracker web interface to debug. I get this
behavior no matter what size the input file is. I've been hacking on this
for a full day and am ready to pull my hair out. The output looks like
this:
13/09/12 15:12:14 INFO util.NativeCodeLoader: Loaded the native-hadoop
library
13/09/12 15:12:14 WA
RN mapred.JobClient: Use GenericOptionsParser for parsing the arguments.
Applications should implement Tool for the same.
13/09/12 15:12:14 INFO input.FileInputFormat: Total input paths to process
: 1
13/09/12 15:12:14 INFO mapred.JobClient: Running job:
job_local1132137425_0001
13/09/12 15:12:14 INFO mapred.LocalJobRunner: Waiting for map tasks
13/09/12 15:12:14 INFO mapred.LocalJobRunner: Starting task:
attempt_local1132137425_0001_m_000000_0
13/09/12 15:12:14 INFO util.ProcessTree: setsid exited with exit code 0
13/09/12 15:12:14 INFO mapred.Task: Using ResourceCalculatorPlugin :
org.apache.hadoop.util.LinuxResourceCalculatorPlugin@339c98d3
13/09/12 15:12:14 INFO mapred.MapTask: Processing split:
file:/home/axelmagn/EclipseWorkspace/AxelMagnusonCoursework/assign-2/data/in/input.csv:0+33554432
13/09/12 15:12:14 WARN snappy.LoadSnappy: Snappy native library not loaded
13/09/12 15:12:14 INFO mapred.MapTask: io.sort.mb = 100
13/09/12 15:12:14 INFO mapred.MapTask: data buffer = 79691776/99614720
13/09/12 15:12:14 INFO mapred.MapTask: record buffer = 262144/327680
13/09/12 15:12:15 INFO mapred.JobClient: map 0% reduce 0%
13/09/12 15:12:15 INFO mapred.MapTask: Starting flush of map output
13/09/12 15:12:15 INFO mapred.MapTask: Starting flush of map output
13/09/12 15:12:20 INFO mapred.LocalJobRunner:
13/09/12 15:12:21 INFO mapred.JobClient: map 20% reduce 0%
and then it just hangs indefinitely.
The Tool routine (abridged):
tempPath = new Path("/tmp/" + outDirPath.getName() + "_1_" + now);
tempPath2 = new Path("/tmp/" + outDirPath.getName() + "_2_" + now);
job1 = new VisitorCountJob(inFilePath, tempPath);
success = job1.waitForCompletion(true);
if (!success)
throw new Exception("Visitor Count Job Failed.");
job2 = new TopVisitorJob(tempPath, outDirPath, TOPN);
success = job2.waitForCompletion(true);
return success ? 0 : 1;
The Job:
public class VisitorCountJob extends Job {
public static final String TAB = "\t";
public VisitorCountJob(Path inputPath, Path outputPath)
throws IOException {
super();
this.setJarByClass(VisitorCountJob.class);
this.setJobName("Visitor Count");
this.setInputFormatClass(VisitInputFormat.class);
VisitInputFormat.setInputPaths(this, inputPath);
FileOutputFormat.setOutputPath(this, outputPath);
this.setMapperClass(VisitorCountMapper.class);
this.setReducerClass(VisitorCountReducer.class);
this.setOutputKeyClass(Person.class);
this.setOutputValueClass(IntWritable.class);
this.setOutputFormatClass(SequenceFileOutputFormat.class);
}
}
The Mapper:
public class VisitorCountMapper extends
Mapper<LongWritable, Visit, Person, IntWritable> {
@Override
public void map(LongWritable key, Visit value, Context context)
throws IOException, InterruptedException {
try {
Person visitor = value.getVisitor();
context.write(visitor, new IntWritable(1));
} catch (IOException e) {
e.printStackTrace();
throw e;
} catch (InterruptedException e) {
e.printStackTrace();
throw e;
}
}
}
The reducer:
public class VisitorCountReducer extends
Reducer<Person, IntWritable, Person, IntWritable> {
@Override
public void reduce(Person visitor, Iterable<IntWritable> values,
Context context) throws IOException, InterruptedException {
int count = 0;
for (IntWritable value : values) {
count += value.get();
}
context.write(visitor, new IntWritable(count));
}
}
I've also written an InputFormat and RecordReader to generate Visit
objects from raw text, but I'll leave them out for brevity unless anyone
thinks they're relevant.
I'm really at my wit's end, so any help is very appreciated.
edit: due to expressed interest, here are some of my data type
implementations:
Person:
public class Person implements WritableComparable<Person> {
public Text firstName;
public Text lastName;
public Person() {}
public Person(Text firstName, Text lastName) {
this.firstName = firstName;
this.lastName = lastName;
}
public Person(String firstName, String lastName) {
this(new Text(firstName), new Text(lastName));
}
public void readFields(DataInput in) throws IOException {
firstName.readFields(in);
lastName.readFields(in);
}
public void write(DataOutput out) throws IOException {
firstName.write(out);
lastName.write(out);
}
public int compareTo(Person other) {
int out;
// give sorting preference to first name
out = firstName.compareTo(other.firstName);
if(out != 0)
return out;
return lastName.compareTo(other.lastName);
}
}
VisitInputFormat:
public class VisitInputFormat extends FileInputFormat<LongWritable, Visit> {
public RecordReader<LongWritable, Visit> createRecordReader(
InputSplit split, TaskAttemptContext context)
throws IOException, InterruptedException {
VisitRecordReader reader = new VisitRecordReader();
reader.initialize(split, context);
return reader;
}
}
VisitRecordReader:
public class VisitRecordReader extends RecordReader<LongWritable, Visit> {
private LineRecordReader lineReader;
private LongWritable lineKey;
private Text lineValue;
public VisitRecordReader() {
lineReader = new LineRecordReader();
}
public void initialize(InputSplit genericSplit, TaskAttemptContext
context)
throws IOException {
lineReader.initialize(genericSplit, context);
}
public boolean nextKeyValue() throws IOException {
return lineReader.nextKeyValue();
}
public LongWritable getCurrentKey() {
return lineReader.getCurrentKey();
}
public Visit getCurrentValue() {
String raw = lineReader.getCurrentValue().toString();
return new Visit(raw);
}
public float getProgress() throws IOException {
return lineReader.getProgress();
}
public void close() throws IOException {
lineReader.close();
}
}