src/main/java/org/apache/accumulo/testing/stress/Scan.java

/*
 * 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
 *
 *   https://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 org.apache.accumulo.testing.stress;

import java.util.ArrayList;
import java.util.Iterator;
import java.util.Random;

import org.apache.accumulo.core.client.Accumulo;
import org.apache.accumulo.core.client.AccumuloClient;
import org.apache.accumulo.core.client.AccumuloException;
import org.apache.accumulo.core.client.AccumuloSecurityException;
import org.apache.accumulo.core.client.Scanner;
import org.apache.accumulo.core.client.TableNotFoundException;
import org.apache.accumulo.core.client.admin.TableOperations;
import org.apache.accumulo.core.data.Range;
import org.apache.accumulo.core.security.Authorizations;
import org.apache.hadoop.io.Text;

import com.google.common.collect.Lists;

public class Scan {

  public static void main(String[] args) throws Exception {
    ScanOpts opts = new ScanOpts();
    opts.parseArgs(Scan.class.getName(), args);

    try (AccumuloClient client = Accumulo.newClient().from(opts.getClientProps()).build();
        Scanner scanner = client.createScanner(opts.tableName, new Authorizations())) {
      if (opts.isolate) {
        scanner.enableIsolation();
      }

      Random tablet_index_generator = new Random(opts.scan_seed);

      LoopControl scanning_condition = opts.continuous ? new ContinuousLoopControl()
          : new IterativeLoopControl(opts.scan_iterations);

      while (scanning_condition.keepScanning()) {
        Range range = pickRange(client.tableOperations(), opts.tableName, tablet_index_generator);
        scanner.setRange(range);
        if (opts.batch_size > 0) {
          scanner.setBatchSize(opts.batch_size);
        }
        try {
          consume(scanner);
        } catch (Exception e) {
          System.err.println(String.format(
              "Exception while scanning range %s. Check the state of Accumulo for errors.", range));
          throw e;
        }
      }
    }
  }

  public static void consume(Iterable<?> iterable) {
    Iterator<?> itr = iterable.iterator();
    while (itr.hasNext()) {
      itr.next();
    }
  }

  public static Range pickRange(TableOperations tops, String table, Random r)
      throws TableNotFoundException, AccumuloSecurityException, AccumuloException {
    ArrayList<Text> splits = Lists.newArrayList(tops.listSplits(table));
    if (splits.isEmpty()) {
      return new Range();
    } else {
      int index = r.nextInt(splits.size());
      Text endRow = splits.get(index);
      Text startRow = index == 0 ? null : splits.get(index - 1);
      return new Range(startRow, false, endRow, true);
    }
  }

  /*
   * These interfaces + implementations are used to determine how many times the scanner should look
   * up a random tablet and scan it.
   */
  interface LoopControl {
    boolean keepScanning();
  }

  // Does a finite number of iterations
  static class IterativeLoopControl implements LoopControl {
    private final int max;
    private int current;

    public IterativeLoopControl(int max) {
      this.max = max;
      this.current = 0;
    }

    @Override
    public boolean keepScanning() {
      if (current < max) {
        ++current;
        return true;
      } else {
        return false;
      }
    }
  }

  // Does an infinite number of iterations
  static class ContinuousLoopControl implements LoopControl {
    @Override
    public boolean keepScanning() {
      return true;
    }
  }
}