goraci.Walker.java Source code

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Here is the source code for goraci.Walker.java

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/**
 * Licensed to the Apache Software Foundation (ASF) under one or more
 * contributor license agreements.  See the NOTICE file distributed with
 * this work for additional information regarding copyright ownership.
 * The ASF licenses this file to You 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 goraci;

import goraci.generated.CINode;

import java.io.IOException;
import java.util.Random;

import org.apache.commons.cli.CommandLine;
import org.apache.commons.cli.GnuParser;
import org.apache.commons.cli.HelpFormatter;
import org.apache.commons.cli.Options;
import org.apache.commons.cli.ParseException;
import org.apache.gora.query.Query;
import org.apache.gora.query.Result;
import org.apache.gora.store.DataStore;
import org.apache.gora.store.DataStoreFactory;
import org.apache.hadoop.conf.Configuration;
import org.apache.hadoop.conf.Configured;
import org.apache.hadoop.util.Tool;
import org.apache.hadoop.util.ToolRunner;

/**
 * A stand alone program that follows a linked list created by {@link Generator} and prints timing info.
 */
public class Walker extends Configured implements Tool {

    private static final String[] PREV_FIELD = new String[] { "prev" };

    public int run(String[] args) throws IOException {
        Options options = new Options();
        options.addOption("n", "num", true, "number of queries");

        GnuParser parser = new GnuParser();
        CommandLine cmd = null;
        try {
            cmd = parser.parse(options, args);
            if (cmd.getArgs().length != 0) {
                throw new ParseException("Command takes no arguments");
            }
        } catch (ParseException e) {
            System.err.println("Failed to parse command line " + e.getMessage());
            System.err.println();
            HelpFormatter formatter = new HelpFormatter();
            formatter.printHelp(getClass().getSimpleName(), options);
            System.exit(-1);
        }

        long maxQueries = Long.MAX_VALUE;
        if (cmd.hasOption('n')) {
            maxQueries = Long.parseLong(cmd.getOptionValue("n"));
        }

        DataStore<Long, CINode> store = DataStoreFactory.getDataStore(Long.class, CINode.class,
                new Configuration());

        Random rand = new Random();

        long numQueries = 0;

        while (numQueries < maxQueries) {
            CINode node = findStartNode(rand, store);
            numQueries++;
            while (node != null && node.getPrev() >= 0 && numQueries < maxQueries) {
                long prev = node.getPrev();

                long t1 = System.currentTimeMillis();
                node = store.get(prev, PREV_FIELD);
                long t2 = System.currentTimeMillis();
                System.out.printf("CQ %d %016x \n", t2 - t1, prev);
                numQueries++;

                t1 = System.currentTimeMillis();
                node = store.get(prev, PREV_FIELD);
                t2 = System.currentTimeMillis();
                System.out.printf("HQ %d %016x \n", t2 - t1, prev);
                numQueries++;

            }
        }

        store.close();
        return 0;
    }

    private static CINode findStartNode(Random rand, DataStore<Long, CINode> store) throws IOException {
        Query<Long, CINode> query = store.newQuery();
        query.setStartKey(rand.nextLong());
        query.setLimit(1);
        query.setFields(PREV_FIELD);

        long t1 = System.currentTimeMillis();
        Result<Long, CINode> rs = store.execute(query);
        long t2 = System.currentTimeMillis();

        if (rs.next()) {
            System.out.printf("FSR %d %016x\n", t2 - t1, rs.getKey());
            return rs.get();
        }

        System.out.println("FSR " + (t2 - t1));

        return null;
    }

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

}