edu.yale.cs.hadoopdb.benchmark.GrepTaskDB.java Source code

Introduction

Here is the source code for edu.yale.cs.hadoopdb.benchmark.GrepTaskDB.java

Source

/**
 * Copyright 2009 HadoopDB Team (http://db.cs.yale.edu/hadoopdb/hadoopdb.html)
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 *  limitations under the License.
 */
package edu.yale.cs.hadoopdb.benchmark;

import java.io.IOException;
import java.sql.PreparedStatement;
import java.sql.ResultSet;
import java.sql.SQLException;

import org.apache.hadoop.conf.Configuration;
import org.apache.hadoop.fs.Path;
import org.apache.hadoop.io.LongWritable;
import org.apache.hadoop.io.Text;
import org.apache.hadoop.mapred.FileOutputFormat;
import org.apache.hadoop.mapred.JobConf;
import org.apache.hadoop.mapred.MapReduceBase;
import org.apache.hadoop.mapred.Mapper;
import org.apache.hadoop.mapred.OutputCollector;
import org.apache.hadoop.mapred.Reporter;
import org.apache.hadoop.mapred.TextOutputFormat;
import org.apache.hadoop.util.ToolRunner;

import edu.yale.cs.hadoopdb.connector.DBConst;
import edu.yale.cs.hadoopdb.connector.DBWritable;
import edu.yale.cs.hadoopdb.exec.DBJobBase;
import edu.yale.cs.hadoopdb.util.HDFSUtil;

/**
 * HadoopDB's implementation of Grep Task
 * http://database.cs.brown.edu/projects/mapreduce-vs-dbms/
 */
public class GrepTaskDB extends DBJobBase {

    public static void main(String[] args) throws Exception {
        int res = ToolRunner.run(new Configuration(), new GrepTaskDB(), args);
        System.exit(res);
    }

    static class DocumentsRecord implements DBWritable {
        private String key;
        private String field;

        public String getKey() {
            return key;
        }

        public String getField() {
            return field;
        }

        @Override
        public void readFields(ResultSet resultSet) throws SQLException {
            this.key = resultSet.getString("key1");
            this.field = resultSet.getString("field");
        }

        @Override
        public void write(PreparedStatement statement) throws SQLException {
            throw new UnsupportedOperationException("No write() impl.");
        }
    }

    public static class Map extends MapReduceBase implements Mapper<LongWritable, DocumentsRecord, Text, Text> {

        private Text outputKey = new Text();
        private Text outputValue = new Text();

        @Override
        public void map(LongWritable dummy, DocumentsRecord record, OutputCollector<Text, Text> output,
                Reporter reporter) throws IOException {
            outputKey.set(record.key);
            outputValue.set(record.field);
            output.collect(outputKey, outputValue);
        }
    }

    @Override
    protected JobConf configureJob(String... args) throws IOException {

        JobConf conf = new JobConf(GrepTaskDB.class);
        conf.setJobName("grep_db_job");

        conf.setOutputKeyClass(Text.class);
        conf.setOutputValueClass(Text.class);
        conf.setMapperClass(Map.class);
        conf.setNumReduceTasks(0);

        // GREP arguments
        conf.setOutputFormat(TextOutputFormat.class);
        for (int i = 0; i < args.length; ++i) {
            if ("-pattern".equals(args[i]))
                conf.set("pattern", args[++i]);
            else if ("-output".equals(args[i]))
                conf.set("output", args[++i]);
        }

        // OUTPUT properties

        Path outputPath = new Path(conf.get("output"));
        System.out.println(conf.get("output"));
        HDFSUtil.deletePath(outputPath);
        FileOutputFormat.setOutputPath(conf, outputPath);

        // DB properties
        conf.set(DBConst.DB_RELATION_ID, "grep");
        conf.set(DBConst.DB_RECORD_READER, DocumentsRecord.class.getName());
        conf.set(DBConst.DB_SQL_QUERY,
                "SELECT key1, field FROM grep WHERE field LIKE '%" + conf.get("pattern") + "%';");

        return conf;

    }

    @Override
    protected int printUsage() {
        System.out.println("grep \n-pattern <pattern> \n-output <output file>");
        return -1;
    }

}