/**
* Write a partition file for the given job, using the Sampler provided. Queries the sampler for a
* sample keyset, sorts by the output key comparator, selects the keys for each rank, and writes
* to the destination returned from {@link TotalOrderPartitioner#getPartitionFile}.
*/
@SuppressWarnings("unchecked") // getInputFormat, getOutputKeyComparator
public static <K, V> void writePartitionFile(Job job, Sampler<K, V> sampler)
throws IOException, ClassNotFoundException, InterruptedException {
Configuration conf = job.getConfiguration();
final InputFormat inf = ReflectionUtils.newInstance(job.getInputFormatClass(), conf);
int numPartitions = job.getNumReduceTasks();
K[] samples = sampler.getSample(inf, job);
RawComparator<K> comparator = (RawComparator<K>) job.getSortComparator();
Arrays.sort(samples, comparator);
Path dst = new Path(TotalOrderPartitioner.getPartitionFile(conf));
FileSystem fs = dst.getFileSystem(conf);
if (fs.exists(dst)) {
fs.delete(dst, false);
}
SequenceFile.Writer writer =
SequenceFile.createWriter(fs, conf, dst, job.getMapOutputKeyClass(), NullWritable.class);
NullWritable nullValue = NullWritable.get();
float stepSize = samples.length / (float) numPartitions;
int last = -1;
for (int i = 1; i < numPartitions; ++i) {
int k = Math.round(stepSize * i);
while (last >= k && comparator.compare(samples[last], samples[k]) == 0) {
++k;
}
writer.append(samples[k], nullValue);
last = k;
}
writer.close();
}
/**
* Compares sequentially the fields from two tuples and returns which field they differ from. Use
* custom comparators when provided. The provided RawComparators must implement "compare" so we
* should use them.
*
* <p>Important. The contract of this method is that the tuples will differ always between
* minField and maxField. If they are equal then an Exception is thrown.
*/
private int indexMismatch(ITuple tuple1, ITuple tuple2, int minFieldIndex, int maxFieldIndex) {
int schemaId1 = tupleMRConfig.getSchemaIdByName(tuple1.getSchema().getName());
int schemaId2 = tupleMRConfig.getSchemaIdByName(tuple2.getSchema().getName());
int[] translationTuple1 = serInfo.getGroupSchemaIndexTranslation(schemaId1);
int[] translationTuple2 = serInfo.getGroupSchemaIndexTranslation(schemaId2);
for (int i = minFieldIndex; i <= maxFieldIndex; i++) {
Object obj1 = tuple1.get(translationTuple1[i]);
Object obj2 = tuple2.get(translationTuple2[i]);
@SuppressWarnings("unchecked")
RawComparator<Object> customComparator = (RawComparator<Object>) customComparators[i];
if (customComparator != null) {
if (customComparator.compare(obj1, obj2) != 0) {
return i;
}
} else {
if (!obj1.equals(obj2)) {
return i;
}
}
}
throw new RuntimeException(
"Illegal state.The tuples "
+ tuple1
+ " and "
+ tuple2
+ " compare the same between indexes "
+ minFieldIndex
+ " and "
+ maxFieldIndex);
}
public static void compare2(Integer i, Integer j) throws IOException {
IntWritable w1 = new IntWritable(i);
IntWritable w2 = new IntWritable(j);
byte[] b1 = serialize(w1);
byte[] b2 = serialize(w2);
System.out.println(comparator.compare(b1, 0, b1.length, b2, 0, b2.length));
}
/** Returns the instance files created */
static Set<String> serializeComparators(
Criteria criteria,
Configuration conf,
List<String> comparatorRefs,
List<String> comparatorInstanceFiles,
String prefix)
throws TupleMRException {
Set<String> instanceFiles = new HashSet<String>();
if (criteria == null) {
return instanceFiles;
}
for (SortElement element : criteria.getElements()) {
if (element.getCustomComparator() != null) {
RawComparator<?> comparator = element.getCustomComparator();
if (!(comparator instanceof Serializable)) {
throw new TupleMRException(
"The class '"
+ comparator.getClass().getName()
+ "' is not Serializable."
+ " The customs comparators must implement Serializable.");
}
String ref = prefix + "|" + element.getName();
String uniqueName = UUID.randomUUID().toString() + '.' + "comparator.dat";
try {
InstancesDistributor.distribute(comparator, uniqueName, conf);
instanceFiles.add(uniqueName);
} catch (Exception e) {
throw new TupleMRException(
"The class " + comparator.getClass().getName() + " can't be serialized", e);
}
comparatorRefs.add(ref);
comparatorInstanceFiles.add(uniqueName);
}
}
return instanceFiles;
}
@SuppressWarnings("unchecked")
protected boolean lessThan(Object a, Object b) {
DataInputBuffer key1 = ((Segment<K, V>) a).getKey();
DataInputBuffer key2 = ((Segment<K, V>) b).getKey();
int s1 = key1.getPosition();
int l1 = key1.getLength() - s1;
int s2 = key2.getPosition();
int l2 = key2.getLength() - s2;
return comparator.compare(key1.getData(), s1, l1, key2.getData(), s2, l2) < 0;
}
/**
* Compare logical range, st i, j MOD offset capacity. Compare by partition, then by key.
*
* @see IndexedSortable#compare
*/
public int compare(int i, int j) {
final int ii = kvoffsets[i % kvoffsets.length];
final int ij = kvoffsets[j % kvoffsets.length];
// sort by partition
if (kvindices[ii + PARTITION] != kvindices[ij + PARTITION]) {
return kvindices[ii + PARTITION] - kvindices[ij + PARTITION];
}
// sort by key
return comparator.compare(
kvbuffer,
kvindices[ii + KEYSTART],
kvindices[ii + VALSTART] - kvindices[ii + KEYSTART],
kvbuffer,
kvindices[ij + KEYSTART],
kvindices[ij + VALSTART] - kvindices[ij + KEYSTART]);
}
public static void compare(Integer i, Integer j) {
IntWritable w1 = new IntWritable(i);
IntWritable w2 = new IntWritable(j);
System.out.println(comparator.compare(w1, w2));
}
