@Override
@SuppressWarnings("unchecked")
public void run(final JobConf job, final TaskUmbilicalProtocol umbilical) throws IOException {
final Reporter reporter = getReporter(umbilical);
// start thread that will handle communication with parent
startCommunicationThread(umbilical);
int numReduceTasks = conf.getNumReduceTasks();
LOG.info("numReduceTasks: " + numReduceTasks);
MapOutputCollector collector = null;
if (numReduceTasks > 0) {
collector = new MapOutputBuffer(umbilical, job, reporter);
} else {
collector = new DirectMapOutputCollector(umbilical, job, reporter);
}
// reinstantiate the split
try {
instantiatedSplit =
(InputSplit) ReflectionUtils.newInstance(job.getClassByName(splitClass), job);
} catch (ClassNotFoundException exp) {
IOException wrap = new IOException("Split class " + splitClass + " not found");
wrap.initCause(exp);
throw wrap;
}
DataInputBuffer splitBuffer = new DataInputBuffer();
splitBuffer.reset(split.get(), 0, split.getSize());
instantiatedSplit.readFields(splitBuffer);
// if it is a file split, we can give more details
if (instantiatedSplit instanceof FileSplit) {
FileSplit fileSplit = (FileSplit) instantiatedSplit;
job.set("map.input.file", fileSplit.getPath().toString());
job.setLong("map.input.start", fileSplit.getStart());
job.setLong("map.input.length", fileSplit.getLength());
}
RecordReader rawIn = // open input
job.getInputFormat().getRecordReader(instantiatedSplit, job, reporter);
RecordReader in = new TrackedRecordReader(rawIn, getCounters());
MapRunnable runner = (MapRunnable) ReflectionUtils.newInstance(job.getMapRunnerClass(), job);
try {
runner.run(in, collector, reporter);
collector.flush();
} finally {
// close
in.close(); // close input
collector.close();
}
done(umbilical);
}
@Test
public void testSplitableCodecs() throws IOException {
JobConf conf = new JobConf(defaultConf);
int seed = new Random().nextInt();
// Create the codec
CompressionCodec codec = null;
try {
codec =
(CompressionCodec)
ReflectionUtils.newInstance(
conf.getClassByName("org.apache.hadoop.io.compress.BZip2Codec"), conf);
} catch (ClassNotFoundException cnfe) {
throw new IOException("Illegal codec!");
}
Path file = new Path(workDir, "test" + codec.getDefaultExtension());
// A reporter that does nothing
Reporter reporter = Reporter.NULL;
LOG.info("seed = " + seed);
Random random = new Random(seed);
FileSystem localFs = FileSystem.getLocal(conf);
localFs.delete(workDir, true);
FileInputFormat.setInputPaths(conf, workDir);
final int MAX_LENGTH = 500000;
// for a variety of lengths
for (int length = MAX_LENGTH / 2;
length < MAX_LENGTH;
length += random.nextInt(MAX_LENGTH / 4) + 1) {
LOG.info("creating; entries = " + length);
// create a file with length entries
Writer writer = new OutputStreamWriter(codec.createOutputStream(localFs.create(file)));
try {
for (int i = 0; i < length; i++) {
writer.write(Integer.toString(i));
writer.write("\n");
}
} finally {
writer.close();
}
// try splitting the file in a variety of sizes
TextInputFormat format = new TextInputFormat();
format.configure(conf);
LongWritable key = new LongWritable();
Text value = new Text();
for (int i = 0; i < 3; i++) {
int numSplits = random.nextInt(MAX_LENGTH / 2000) + 1;
LOG.info("splitting: requesting = " + numSplits);
InputSplit[] splits = format.getSplits(conf, numSplits);
LOG.info("splitting: got = " + splits.length);
// check each split
BitSet bits = new BitSet(length);
for (int j = 0; j < splits.length; j++) {
LOG.debug("split[" + j + "]= " + splits[j]);
RecordReader<LongWritable, Text> reader =
format.getRecordReader(splits[j], conf, reporter);
try {
int counter = 0;
while (reader.next(key, value)) {
int v = Integer.parseInt(value.toString());
LOG.debug("read " + v);
if (bits.get(v)) {
LOG.warn(
"conflict with " + v + " in split " + j + " at position " + reader.getPos());
}
assertFalse("Key in multiple partitions.", bits.get(v));
bits.set(v);
counter++;
}
if (counter > 0) {
LOG.info("splits[" + j + "]=" + splits[j] + " count=" + counter);
} else {
LOG.debug("splits[" + j + "]=" + splits[j] + " count=" + counter);
}
} finally {
reader.close();
}
}
assertEquals("Some keys in no partition.", length, bits.cardinality());
}
}
}
