@SuppressWarnings("unchecked")
public MapOutputBuffer(TaskUmbilicalProtocol umbilical, JobConf job, Reporter reporter)
throws IOException {
this.job = job;
this.reporter = reporter;
localFs = FileSystem.getLocal(job);
partitions = job.getNumReduceTasks();
partitioner = (Partitioner) ReflectionUtils.newInstance(job.getPartitionerClass(), job);
// sanity checks
final float spillper = job.getFloat("io.sort.spill.percent", (float) 0.8);
final float recper = job.getFloat("io.sort.record.percent", (float) 0.05);
final int sortmb = job.getInt("io.sort.mb", 100);
if (spillper > (float) 1.0 || spillper < (float) 0.0) {
throw new IOException("Invalid \"io.sort.spill.percent\": " + spillper);
}
if (recper > (float) 1.0 || recper < (float) 0.01) {
throw new IOException("Invalid \"io.sort.record.percent\": " + recper);
}
if ((sortmb & 0x7FF) != sortmb) {
throw new IOException("Invalid \"io.sort.mb\": " + sortmb);
}
sorter =
(IndexedSorter)
ReflectionUtils.newInstance(job.getClass("map.sort.class", QuickSort.class), job);
LOG.info("io.sort.mb = " + sortmb);
// buffers and accounting
int maxMemUsage = sortmb << 20;
int recordCapacity = (int) (maxMemUsage * recper);
recordCapacity -= recordCapacity % RECSIZE;
kvbuffer = new byte[maxMemUsage - recordCapacity];
bufvoid = kvbuffer.length;
recordCapacity /= RECSIZE;
kvoffsets = new int[recordCapacity];
kvindices = new int[recordCapacity * ACCTSIZE];
softBufferLimit = (int) (kvbuffer.length * spillper);
softRecordLimit = (int) (kvoffsets.length * spillper);
LOG.info("data buffer = " + softBufferLimit + "/" + kvbuffer.length);
LOG.info("record buffer = " + softRecordLimit + "/" + kvoffsets.length);
// k/v serialization
comparator = job.getOutputKeyComparator();
keyClass = (Class<K>) job.getMapOutputKeyClass();
valClass = (Class<V>) job.getMapOutputValueClass();
serializationFactory = new SerializationFactory(job);
keySerializer = serializationFactory.getSerializer(keyClass);
keySerializer.open(bb);
valSerializer = serializationFactory.getSerializer(valClass);
valSerializer.open(bb);
// counters
Counters counters = getCounters();
mapOutputByteCounter = counters.findCounter(MAP_OUTPUT_BYTES);
mapOutputRecordCounter = counters.findCounter(MAP_OUTPUT_RECORDS);
combineInputCounter = counters.findCounter(COMBINE_INPUT_RECORDS);
combineOutputCounter = counters.findCounter(COMBINE_OUTPUT_RECORDS);
// compression
if (job.getCompressMapOutput()) {
Class<? extends CompressionCodec> codecClass =
job.getMapOutputCompressorClass(DefaultCodec.class);
codec = (CompressionCodec) ReflectionUtils.newInstance(codecClass, job);
}
// combiner
combinerClass = job.getCombinerClass();
combineCollector =
(null != combinerClass) ? new CombineOutputCollector(combineOutputCounter) : null;
minSpillsForCombine = job.getInt("min.num.spills.for.combine", 3);
}
