Examples with InputSampler org.apache.hadoop.mapred.lib.InputSampler used on opensource projects

Example 1 with InputSampler

use of org.apache.hadoop.mapred.lib.InputSampler in project hadoop-book by elephantscale.

the class Sort method run.

/**
   * The main driver for sort program.
   * Invoke this method to submit the map/reduce job.
   * @throws IOException When there is communication problems with the 
   *                     job tracker.
   */
public int run(String[] args) throws Exception {
    JobConf jobConf = new JobConf(getConf(), Sort.class);
    jobConf.setJobName("sorter");
    jobConf.setMapperClass(IdentityMapper.class);
    jobConf.setReducerClass(IdentityReducer.class);
    JobClient client = new JobClient(jobConf);
    ClusterStatus cluster = client.getClusterStatus();
    int num_reduces = (int) (cluster.getMaxReduceTasks() * 0.9);
    String sort_reduces = jobConf.get("test.sort.reduces_per_host");
    if (sort_reduces != null) {
        num_reduces = cluster.getTaskTrackers() * Integer.parseInt(sort_reduces);
    }
    Class<? extends InputFormat> inputFormatClass = SequenceFileInputFormat.class;
    Class<? extends OutputFormat> outputFormatClass = SequenceFileOutputFormat.class;
    Class<? extends WritableComparable> outputKeyClass = BytesWritable.class;
    Class<? extends Writable> outputValueClass = BytesWritable.class;
    List<String> otherArgs = new ArrayList<String>();
    InputSampler.Sampler<K, V> sampler = null;
    for (int i = 0; i < args.length; ++i) {
        try {
            if ("-m".equals(args[i])) {
                jobConf.setNumMapTasks(Integer.parseInt(args[++i]));
            } else if ("-r".equals(args[i])) {
                num_reduces = Integer.parseInt(args[++i]);
            } else if ("-inFormat".equals(args[i])) {
                inputFormatClass = Class.forName(args[++i]).asSubclass(InputFormat.class);
            } else if ("-outFormat".equals(args[i])) {
                outputFormatClass = Class.forName(args[++i]).asSubclass(OutputFormat.class);
            } else if ("-outKey".equals(args[i])) {
                outputKeyClass = Class.forName(args[++i]).asSubclass(WritableComparable.class);
            } else if ("-outValue".equals(args[i])) {
                outputValueClass = Class.forName(args[++i]).asSubclass(Writable.class);
            } else if ("-totalOrder".equals(args[i])) {
                double pcnt = Double.parseDouble(args[++i]);
                int numSamples = Integer.parseInt(args[++i]);
                int maxSplits = Integer.parseInt(args[++i]);
                if (0 >= maxSplits)
                    maxSplits = Integer.MAX_VALUE;
                sampler = new InputSampler.RandomSampler<K, V>(pcnt, numSamples, maxSplits);
            } else {
                otherArgs.add(args[i]);
            }
        } catch (NumberFormatException except) {
            System.out.println("ERROR: Integer expected instead of " + args[i]);
            return printUsage();
        } catch (ArrayIndexOutOfBoundsException except) {
            System.out.println("ERROR: Required parameter missing from " + args[i - 1]);
            // exits
            return printUsage();
        }
    }
    // Set user-supplied (possibly default) job configs
    jobConf.setNumReduceTasks(num_reduces);
    jobConf.setInputFormat(inputFormatClass);
    jobConf.setOutputFormat(outputFormatClass);
    jobConf.setOutputKeyClass(outputKeyClass);
    jobConf.setOutputValueClass(outputValueClass);
    // Make sure there are exactly 2 parameters left.
    if (otherArgs.size() != 2) {
        System.out.println("ERROR: Wrong number of parameters: " + otherArgs.size() + " instead of 2.");
        return printUsage();
    }
    FileInputFormat.setInputPaths(jobConf, otherArgs.get(0));
    FileOutputFormat.setOutputPath(jobConf, new Path(otherArgs.get(1)));
    if (sampler != null) {
        System.out.println("Sampling input to effect total-order sort...");
        jobConf.setPartitionerClass(TotalOrderPartitioner.class);
        Path inputDir = FileInputFormat.getInputPaths(jobConf)[0];
        inputDir = inputDir.makeQualified(inputDir.getFileSystem(jobConf));
        Path partitionFile = new Path(inputDir, "_sortPartitioning");
        TotalOrderPartitioner.setPartitionFile(jobConf, partitionFile);
        InputSampler.<K, V>writePartitionFile(jobConf, sampler);
        URI partitionUri = new URI(partitionFile.toString() + "#" + "_sortPartitioning");
        DistributedCache.addCacheFile(partitionUri, jobConf);
        DistributedCache.createSymlink(jobConf);
    }
    System.out.println("Running on " + cluster.getTaskTrackers() + " nodes to sort from " + FileInputFormat.getInputPaths(jobConf)[0] + " into " + FileOutputFormat.getOutputPath(jobConf) + " with " + num_reduces + " reduces.");
    Date startTime = new Date();
    System.out.println("Job started: " + startTime);
    jobResult = JobClient.runJob(jobConf);
    Date end_time = new Date();
    System.out.println("Job ended: " + end_time);
    System.out.println("The job took " + (end_time.getTime() - startTime.getTime()) / 1000 + " seconds.");
    return 0;
}