001/*
002 * Licensed to the Apache Software Foundation (ASF) under one
003 * or more contributor license agreements.  See the NOTICE file
004 * distributed with this work for additional information
005 * regarding copyright ownership.  The ASF licenses this file
006 * to you under the Apache License, Version 2.0 (the
007 * "License"); you may not use this file except in compliance
008 * with the License.  You may obtain a copy of the License at
009 *
010 *     http://www.apache.org/licenses/LICENSE-2.0
011 *
012 * Unless required by applicable law or agreed to in writing, software
013 * distributed under the License is distributed on an "AS IS" BASIS,
014 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
015 * See the License for the specific language governing permissions and
016 * limitations under the License.
017 */
018package org.apache.hadoop.hbase.client;
019
020import static org.junit.jupiter.api.Assertions.assertArrayEquals;
021import static org.junit.jupiter.api.Assertions.assertEquals;
022import static org.junit.jupiter.api.Assertions.assertTrue;
023
024import java.io.IOException;
025import org.apache.hadoop.hbase.HBaseTestingUtil;
026import org.apache.hadoop.hbase.TableName;
027import org.apache.hadoop.hbase.client.Scan.ReadType;
028import org.apache.hadoop.hbase.testclassification.MediumTests;
029import org.apache.hadoop.hbase.util.Bytes;
030import org.junit.jupiter.api.AfterAll;
031import org.junit.jupiter.api.AfterEach;
032import org.junit.jupiter.api.BeforeAll;
033import org.junit.jupiter.api.Tag;
034import org.junit.jupiter.api.Test;
035import org.slf4j.Logger;
036import org.slf4j.LoggerFactory;
037
038@Tag(MediumTests.TAG)
039public class TestPreadReversedScanner {
040
041  public static final Logger LOG = LoggerFactory.getLogger(TestPreadReversedScanner.class);
042  private final static HBaseTestingUtil TEST_UTIL = new HBaseTestingUtil();
043
044  private static final TableName TABLE_NAME = TableName.valueOf("testPreadSmall");
045  private static final byte[] COLUMN_FAMILY = Bytes.toBytes("columnFamily");
046
047  private static Table htable = null;
048
049  @BeforeAll
050  public static void setUpBeforeClass() throws Exception {
051    TEST_UTIL.startMiniCluster(1);
052
053    // create a table with 4 region: (-oo, b),[b,c),[c,d),[d,+oo)
054    byte[] bytes = Bytes.toBytes("bcd");
055    byte[][] splitKeys = new byte[bytes.length][];
056
057    for (int i = 0; i < bytes.length; i++) {
058      splitKeys[i] = new byte[] { bytes[i] };
059    }
060    htable = TEST_UTIL.createTable(TABLE_NAME, COLUMN_FAMILY, splitKeys);
061  }
062
063  @AfterAll
064  public static void tearDownAfterClass() throws Exception {
065    TEST_UTIL.shutdownMiniCluster();
066  }
067
068  @AfterEach
069  public void tearDown() throws IOException {
070    TEST_UTIL.truncateTable(TABLE_NAME);
071  }
072
073  /**
074   * all rowKeys are fit in the last region.
075   */
076  @Test
077  public void testPreadReversedScan01() throws IOException {
078    String[][] keysCases = new String[][] { { "d0", "d1", "d2", "d3" }, // all rowKeys fit in the
079                                                                        // last region.
080      { "a0", "a1", "a2", "a3" }, // all rowKeys fit in the first region.
081      { "a0", "b1", "c2", "d3" }, // each region with a rowKey
082    };
083
084    for (int caseIndex = 0; caseIndex < keysCases.length; caseIndex++) {
085      testPreadReversedScanInternal(keysCases[caseIndex]);
086      TEST_UTIL.truncateTable(TABLE_NAME);
087    }
088  }
089
090  private void testPreadReversedScanInternal(String[] inputRowKeys) throws IOException {
091    int rowCount = inputRowKeys.length;
092
093    for (int i = 0; i < rowCount; i++) {
094      Put put = new Put(Bytes.toBytes(inputRowKeys[i]));
095      put.addColumn(COLUMN_FAMILY, null, Bytes.toBytes(i));
096      htable.put(put);
097    }
098
099    Scan scan = new Scan();
100    scan.setReversed(true);
101    scan.setReadType(ReadType.PREAD);
102
103    ResultScanner scanner = htable.getScanner(scan);
104    Result r;
105    int value = rowCount;
106    while ((r = scanner.next()) != null) {
107      assertArrayEquals(r.getValue(COLUMN_FAMILY, null), Bytes.toBytes(--value));
108      assertArrayEquals(r.getRow(), Bytes.toBytes(inputRowKeys[value]));
109    }
110
111    assertEquals(0, value);
112  }
113
114  /**
115   * Corner case:
116   * <p/>
117   * HBase has 4 regions, (-oo,b),[b,c),[c,d),[d,+oo), and only rowKey with byte[]={0x00} locate in
118   * region (-oo,b) . test whether reversed pread scanner will return infinity results with
119   * RowKey={0x00}.
120   */
121  @Test
122  public void testSmallReversedScan02() throws IOException {
123    Put put = new Put(new byte[] { (char) 0x00 });
124    put.addColumn(COLUMN_FAMILY, null, Bytes.toBytes(0));
125    htable.put(put);
126
127    Scan scan = new Scan();
128    scan.setCaching(1);
129    scan.setReversed(true);
130    scan.setReadType(ReadType.PREAD);
131
132    ResultScanner scanner = htable.getScanner(scan);
133    Result r;
134    int count = 1;
135    while ((r = scanner.next()) != null) {
136      assertArrayEquals(r.getValue(COLUMN_FAMILY, null), Bytes.toBytes(0));
137      assertArrayEquals(r.getRow(), new byte[] { (char) 0x00 });
138      assertTrue(--count >= 0);
139    }
140    assertEquals(0, count);
141  }
142}