org.apache.hadoop.hbase.regionserver.HRegion Java Examples

private HRegion updateTtl(HRegion region, byte[] family, long ttl) throws Exception {
  region.close();
  TableDescriptorBuilder tableBuilder =
      TableDescriptorBuilder.newBuilder(region.getTableDescriptor());
  ColumnFamilyDescriptorBuilder cfd =
      ColumnFamilyDescriptorBuilder.newBuilder(tableBuilder.build().getColumnFamily(family));
  if (ttl > 0) {
    cfd.setValue(Bytes.toBytes(TxConstants.PROPERTY_TTL), Bytes.toBytes(String.valueOf(ttl)));
  }
  cfd.setMaxVersions(10);
  tableBuilder.removeColumnFamily(family);
  tableBuilder.addColumnFamily(cfd.build());
  return HRegion
      .openHRegion(region.getRegionInfo(), tableBuilder.build(), region.getWAL(), conf,
        new LocalRegionServerServices(conf, ServerName
            .valueOf(InetAddress.getLocalHost().getHostName(), 0, System.currentTimeMillis())),
        null);
}
 

public void splitStats(HRegion parent, HRegion left, HRegion right) {
    try {
        if (logger.isDebugEnabled()) {
            logger.debug("Collecting stats for split of " + parent.getRegionInfo() + " into " + left.getRegionInfo() + " and " + right.getRegionInfo());
        }
        List<Mutation> mutations = Lists.newArrayListWithExpectedSize(3);
        for (byte[] fam : parent.getStores().keySet()) {
        	statsTable.splitStats(parent, left, right, this, new ImmutableBytesPtr(fam), mutations);
        }
        if (logger.isDebugEnabled()) {
            logger.debug("Committing stats for the daughter regions as part of split " + parent.getRegionInfo());
        }
        commitStats(mutations);
    } catch (IOException e) {
        logger.error("Error while capturing stats after split of region "
                + parent.getRegionInfo().getRegionNameAsString(), e);
    }
}
 

private HRegion createRegion(String tableName, byte[] family, long ttl) throws IOException {
  HTableDescriptor htd = new HTableDescriptor(TableName.valueOf(tableName));
  HColumnDescriptor cfd = new HColumnDescriptor(family);
  if (ttl > 0) {
    cfd.setValue(TxConstants.PROPERTY_TTL, String.valueOf(ttl));
  }
  cfd.setMaxVersions(10);
  htd.addFamily(cfd);
  htd.addCoprocessor(TransactionProcessor.class.getName());
  Path tablePath = FSUtils.getTableDir(FSUtils.getRootDir(conf), htd.getTableName());
  FileSystem fs = FileSystem.get(conf);
  assertTrue(fs.mkdirs(tablePath));
  WALFactory walFactory = new WALFactory(conf, null, tableName + ".hlog");
  WAL hLog = walFactory.getWAL(new byte[]{1}, null);
  HRegionInfo regionInfo = new HRegionInfo(TableName.valueOf(tableName));
  HRegionFileSystem regionFS = HRegionFileSystem.createRegionOnFileSystem(conf, fs, tablePath, regionInfo);
  return new HRegion(regionFS, hLog, conf, htd,
      new LocalRegionServerServices(conf, ServerName.valueOf(
          InetAddress.getLocalHost().getHostName(), 0, System.currentTimeMillis())));
}
 

@Override
public void postFlush(ObserverContext<RegionCoprocessorEnvironment> e) throws IOException {
  // Record whether the region is empty after a flush
  HRegion region = e.getEnvironment().getRegion();
  // After a flush, if the memstore size is zero and there are no store files for any stores in the region
  // then the region must be empty
  long numStoreFiles = numStoreFilesForRegion(e);
  long memstoreSize = region.getMemstoreSize().get();
  LOG.debug(String.format("Region %s: memstore size = %s, num store files = %s",
                          region.getRegionInfo().getRegionNameAsString(), memstoreSize, numStoreFiles));
  if (memstoreSize == 0 && numStoreFiles == 0) {
    if (compactionState != null) {
      compactionState.persistRegionEmpty(System.currentTimeMillis());
    }
  }
}
 

@Test
public void testRegionCoprocessorHostDefaults() throws Exception {
  Configuration conf = new Configuration(CONF);
  HRegion region = mock(HRegion.class);
  when(region.getRegionInfo()).thenReturn(REGIONINFO);
  when(region.getTableDescriptor()).thenReturn(TABLEDESC);
  RegionServerServices rsServices = mock(RegionServerServices.class);
  systemCoprocessorLoaded.set(false);
  tableCoprocessorLoaded.set(false);
  new RegionCoprocessorHost(region, rsServices, conf);
  assertEquals("System coprocessors loading default was not honored",
      CoprocessorHost.DEFAULT_COPROCESSORS_ENABLED, systemCoprocessorLoaded.get());
  assertEquals("Table coprocessors loading default was not honored",
      CoprocessorHost.DEFAULT_COPROCESSORS_ENABLED &&
      CoprocessorHost.DEFAULT_USER_COPROCESSORS_ENABLED, tableCoprocessorLoaded.get());
}
 

@Override
public void handleRegionEndKeyNotEmpty(byte[] curEndKey) throws IOException {
  errors.reportError(HbckErrorReporter.ERROR_CODE.LAST_REGION_ENDKEY_NOT_EMPTY,
      "Last region should end with an empty key.  Creating a new "
          + "region and regioninfo in HDFS to plug the hole.", getTableInfo());
  TableDescriptor htd = getTableInfo().getTableDescriptor();
  // from curEndKey to EMPTY_START_ROW
  RegionInfo newRegion = RegionInfoBuilder.newBuilder(htd.getTableName())
      .setStartKey(curEndKey)
      .setEndKey(HConstants.EMPTY_START_ROW)
      .build();

  HRegion region = HBaseFsckRepair.createHDFSRegionDir(conf, newRegion, htd);
  LOG.info("Table region end key was not empty.  Created new empty region: " + newRegion
      + " " + region);
  hbck.fixes++;
}
 

private PTable buildDeletedTable(byte[] key, ImmutableBytesPtr cacheKey, HRegion region, long clientTimeStamp) throws IOException {
    if (clientTimeStamp == HConstants.LATEST_TIMESTAMP) {
        return null;
    }
    
    Scan scan = newTableRowsScan(key, clientTimeStamp, HConstants.LATEST_TIMESTAMP);
    scan.setFilter(new FirstKeyOnlyFilter());
    scan.setRaw(true);
    RegionScanner scanner = region.getScanner(scan);
    List<KeyValue> results = Lists.<KeyValue>newArrayList();
    scanner.next(results);
    // HBase ignores the time range on a raw scan (HBASE-7362)
    if (!results.isEmpty() && results.get(0).getTimestamp() > clientTimeStamp) {
        KeyValue kv = results.get(0);
        if (kv.isDelete()) {
            Map<ImmutableBytesPtr,PTable> metaDataCache = GlobalCache.getInstance(this.getEnvironment()).getMetaDataCache();
            PTable table = newDeletedTableMarker(kv.getTimestamp());
            metaDataCache.put(cacheKey, table);
            return table;
        }
    }
    return null;
}
 

private PTable loadTable(RegionCoprocessorEnvironment env, byte[] key,
    ImmutableBytesPtr cacheKey, long clientTimeStamp, long asOfTimeStamp)
    throws IOException, SQLException {
    HRegion region = env.getRegion();
    Cache<ImmutableBytesPtr,PTable> metaDataCache = GlobalCache.getInstance(this.env).getMetaDataCache();
    PTable table = metaDataCache.getIfPresent(cacheKey);
    // We always cache the latest version - fault in if not in cache
    if (table != null || (table = buildTable(key, cacheKey, region, asOfTimeStamp)) != null) {
        return table;
    }
    // if not found then check if newer table already exists and add delete marker for timestamp
    // found
    if (table == null
            && (table = buildDeletedTable(key, cacheKey, region, clientTimeStamp)) != null) {
        return table;
    }
    return null;
}
 

@Before
public void setUp() throws IOException {
  conf = HBaseConfiguration.create();
  region = mock(HRegion.class);
  HStore store = mock(HStore.class);
  when(store.getStorefilesCount()).thenReturn(1);
  when(region.getStores()).thenReturn(Collections.singletonList(store));
  when(region.getRegionInfo())
    .thenReturn(RegionInfoBuilder.newBuilder(TableName.valueOf("hbase:local")).build());
  flushCalled = new AtomicInteger(0);
  memstoreHeapSize = new AtomicLong(0);
  memstoreOffHeapSize = new AtomicLong(0);
  when(region.getMemStoreHeapSize()).thenAnswer(invocation -> memstoreHeapSize.get());
  when(region.getMemStoreOffHeapSize()).thenAnswer(invocation -> memstoreOffHeapSize.get());
  when(region.flush(anyBoolean())).thenAnswer(invocation -> {
    assertTrue(invocation.getArgument(0));
    memstoreHeapSize.set(0);
    memstoreOffHeapSize.set(0);
    flushCalled.incrementAndGet();
    return null;
  });
}
 

HRegion initHRegion(byte[] tableName, String callingMethod, Configuration conf,
    byte[]... families) throws IOException {
  TableDescriptorBuilder.ModifyableTableDescriptor tableDescriptor =
    new TableDescriptorBuilder.ModifyableTableDescriptor(TableName.valueOf(tableName));
  for (byte[] family : families) {
    tableDescriptor.setColumnFamily(
      new ColumnFamilyDescriptorBuilder.ModifyableColumnFamilyDescriptor(family));
  }
  ChunkCreator.initialize(MemStoreLABImpl.CHUNK_SIZE_DEFAULT, false, 0, 0, 0, null);
  RegionInfo info = RegionInfoBuilder.newBuilder(tableDescriptor.getTableName()).build();
  Path path = new Path(DIR + callingMethod);
  WAL wal = HBaseTestingUtility.createWal(conf, path, info);
  HRegion r = HRegion.createHRegion(info, path, conf, tableDescriptor, wal);
  // this following piece is a hack. currently a coprocessorHost
  // is secretly loaded at OpenRegionHandler. we don't really
  // start a region server here, so just manually create cphost
  // and set it to region.
  RegionCoprocessorHost host = new RegionCoprocessorHost(r, null, conf);
  r.setCoprocessorHost(host);
  return r;
}
 

private void moveRegionAndWait(MiniHBaseCluster miniHBaseCluster,HRegion destRegion, HRegionServer destRegionServer) throws IOException, InterruptedException {
    HMaster master = miniHBaseCluster.getMaster();
    getUtility().getHBaseAdmin().move(
            destRegion.getRegionInfo().getEncodedNameAsBytes(),
            Bytes.toBytes(destRegionServer.getServerName().getServerName()));
    while (true) {
        ServerName currentRegionServerName =
                master.getAssignmentManager().getRegionStates().getRegionServerOfRegion(destRegion.getRegionInfo());
        if (currentRegionServerName != null && currentRegionServerName.equals(destRegionServer.getServerName())) {
            getUtility().assertRegionOnServer(
                    destRegion.getRegionInfo(), currentRegionServerName, 200);
            break;
        }
        Thread.sleep(10);
    }
}
 

/**
 * Tests that logs are deleted
 */
@Test
public void testLogRolling() throws Exception {
  this.tableName = getName();
  // TODO: Why does this write data take for ever?
  startAndWriteData();
  RegionInfo region = server.getRegions(TableName.valueOf(tableName)).get(0).getRegionInfo();
  final WAL log = server.getWAL(region);
  LOG.info("after writing there are " + AbstractFSWALProvider.getNumRolledLogFiles(log) + " log files");
  assertLogFileSize(log);

  // flush all regions
  for (HRegion r : server.getOnlineRegionsLocalContext()) {
    r.flush(true);
  }

  // Now roll the log
  log.rollWriter();

  int count = AbstractFSWALProvider.getNumRolledLogFiles(log);
  LOG.info("after flushing all regions and rolling logs there are " + count + " log files");
  assertTrue(("actual count: " + count), count <= 2);
  assertLogFileSize(log);
}
 

@Test
public void testRegionCoprocessorHostAllDisabled() throws Exception {
  Configuration conf = new Configuration(CONF);
  conf.setBoolean(CoprocessorHost.COPROCESSORS_ENABLED_CONF_KEY, false);
  HRegion region = mock(HRegion.class);
  when(region.getRegionInfo()).thenReturn(REGIONINFO);
  when(region.getTableDescriptor()).thenReturn(TABLEDESC);
  RegionServerServices rsServices = mock(RegionServerServices.class);
  systemCoprocessorLoaded.set(false);
  tableCoprocessorLoaded.set(false);
  new RegionCoprocessorHost(region, rsServices, conf);
  assertFalse("System coprocessors should not have been loaded",
    systemCoprocessorLoaded.get());
  assertFalse("Table coprocessors should not have been loaded",
    tableCoprocessorLoaded.get());
}
 

public void verifyNumericRows(HRegion region, final byte[] f, int startRow, int endRow,
    final boolean present) throws IOException {
  for (int i = startRow; i < endRow; i++) {
    String failMsg = "Failed verification of row :" + i;
    byte[] data = Bytes.toBytes(String.valueOf(i));
    Result result = region.get(new Get(data));

    boolean hasResult = result != null && !result.isEmpty();
    assertEquals(failMsg + result, present, hasResult);
    if (!present) continue;

    assertTrue(failMsg, result.containsColumn(f, null));
    assertEquals(failMsg, 1, result.getColumnCells(f, null).size());
    Cell cell = result.getColumnLatestCell(f, null);
    assertTrue(failMsg,
      Bytes.equals(data, 0, data.length, cell.getValueArray(), cell.getValueOffset(),
        cell.getValueLength()));
  }
}
 

public HRegion createLocalHRegionWithInMemoryFlags(TableName tableName, byte[] startKey,
  byte[] stopKey, boolean isReadOnly, Durability durability, WAL wal, boolean[] compactedMemStore,
  byte[]... families) throws IOException {
  TableDescriptorBuilder.ModifyableTableDescriptor tableDescriptor =
    new TableDescriptorBuilder.ModifyableTableDescriptor(tableName);
  tableDescriptor.setReadOnly(isReadOnly);
  int i = 0;
  for (byte[] family : families) {
    ColumnFamilyDescriptorBuilder.ModifyableColumnFamilyDescriptor familyDescriptor =
      new ColumnFamilyDescriptorBuilder.ModifyableColumnFamilyDescriptor(family);
    if (compactedMemStore != null && i < compactedMemStore.length) {
      familyDescriptor.setInMemoryCompaction(MemoryCompactionPolicy.BASIC);
    } else {
      familyDescriptor.setInMemoryCompaction(MemoryCompactionPolicy.NONE);

    }
    i++;
    // Set default to be three versions.
    familyDescriptor.setMaxVersions(Integer.MAX_VALUE);
    tableDescriptor.setColumnFamily(familyDescriptor);
  }
  tableDescriptor.setDurability(durability);
  RegionInfo info = RegionInfoBuilder.newBuilder(tableDescriptor.getTableName())
    .setStartKey(startKey).setEndKey(stopKey).build();
  return createLocalHRegion(info, tableDescriptor, wal);
}
 

private HRegion createRegion(String tableName, byte[] family, long ttl) throws IOException {
  HTableDescriptor htd = new HTableDescriptor(TableName.valueOf(tableName));
  HColumnDescriptor cfd = new HColumnDescriptor(family);
  if (ttl > 0) {
    cfd.setValue(TxConstants.PROPERTY_TTL, String.valueOf(ttl));
  }
  cfd.setMaxVersions(10);
  htd.addFamily(cfd);
  htd.addCoprocessor(TransactionProcessor.class.getName());
  Path tablePath = FSUtils.getTableDir(FSUtils.getRootDir(conf), htd.getTableName());
  FileSystem fs = FileSystem.get(conf);
  assertTrue(fs.mkdirs(tablePath));
  WALFactory walFactory = new WALFactory(conf, null, tableName + ".hlog");
  WAL hLog = walFactory.getWAL(new byte[]{1}, null);
  HRegionInfo regionInfo = new HRegionInfo(TableName.valueOf(tableName));
  HRegionFileSystem regionFS = HRegionFileSystem.createRegionOnFileSystem(conf, fs, tablePath, regionInfo);
  return new HRegion(regionFS, hLog, conf, htd,
      new LocalRegionServerServices(conf, ServerName.valueOf(
          InetAddress.getLocalHost().getHostName(), 0, System.currentTimeMillis())));
}
 

@Test
public void testVisitMetaForRegionExistingRegion() throws Exception {
  final TableName tableName = TableName.valueOf("testVisitMetaForRegion");
  UTIL.createTable(tableName, "cf");
  final List<HRegion> regions = UTIL.getHBaseCluster().getRegions(tableName);
  final String encodedName = regions.get(0).getRegionInfo().getEncodedName();
  final RegionStateStore regionStateStore = UTIL.getHBaseCluster().getMaster().
    getAssignmentManager().getRegionStateStore();
  final AtomicBoolean visitorCalled = new AtomicBoolean(false);
  regionStateStore.visitMetaForRegion(encodedName, new RegionStateStore.RegionStateVisitor() {
    @Override
    public void visitRegionState(Result result, RegionInfo regionInfo, RegionState.State state,
      ServerName regionLocation, ServerName lastHost, long openSeqNum) {
      assertEquals(encodedName, regionInfo.getEncodedName());
      visitorCalled.set(true);
    }
  });
  assertTrue("Visitor has not been called.", visitorCalled.get());
}
 

/**
 * Create a region with it's own WAL. Be sure to call
 * {@link HBaseTestingUtility#closeRegionAndWAL(HRegion)} to clean up all resources.
 */
public static HRegion createRegionAndWAL(final RegionInfo info, final Path rootDir,
    final Configuration conf, final TableDescriptor htd, MobFileCache mobFileCache)
    throws IOException {
  HRegion region = createRegionAndWAL(info, rootDir, conf, htd, false);
  region.setMobFileCache(mobFileCache);
  region.initialize();
  return region;
}
 

private HRegion updateTtl(HRegion region, byte[] family, long ttl) throws Exception {
  region.close();
  HTableDescriptor htd = region.getTableDesc();
  HColumnDescriptor cfd = htd.getFamily(family);
  if (ttl > 0) {
    cfd.setValue(TxConstants.PROPERTY_TTL, String.valueOf(ttl));
  }
  cfd.setMaxVersions(10);
  return HRegion.openHRegion(region.getRegionInfo(), htd, region.getWAL(), conf,
                             new LocalRegionServerServices(conf, ServerName.valueOf(
                               InetAddress.getLocalHost().getHostName(), 0, System.currentTimeMillis())), null);
}
 

/**
 * Creates a 'manifest' for the specified region, by reading directly from the HRegion object.
 * This is used by the "online snapshot" when the table is enabled.
 */
public void addRegion(final HRegion region) throws IOException {
  // Get the ManifestBuilder/RegionVisitor
  RegionVisitor visitor = createRegionVisitor(desc);

  // Visit the region and add it to the manifest
  addRegion(region, visitor);
}
 

/**
 * Call flushCache on all regions of the specified table.
 */
public void flushcache(TableName tableName) throws IOException {
  for (JVMClusterUtil.RegionServerThread t : this.hbaseCluster.getRegionServers()) {
    for (HRegion r : t.getRegionServer().getOnlineRegionsLocalContext()) {
      if (r.getTableDescriptor().getTableName().equals(tableName)) {
        executeFlush(r);
      }
    }
  }
}
 

@SuppressWarnings("StatementWithEmptyBody")
private void scanAndAssert(HRegion region, List<Cell> expected, Scan scan) throws Exception {
  try (RegionScanner regionScanner = region.getScanner(scan)) {
    List<Cell> results = Lists.newArrayList();
    while (regionScanner.next(results)) { }
    assertEquals(expected, results);
  }
}
 

private Set<ServerName> getServersForTable(MiniHBaseCluster cluster, byte[] table)
    throws Exception {
  List<HRegion> indexRegions = cluster.getRegions(table);
  Set<ServerName> indexServers = new HashSet<ServerName>();
  for (HRegion region : indexRegions) {
    indexServers.add(cluster.getServerHoldingRegion(region.getRegionName()));
  }
  return indexServers;
}
 

@Test
public void testDifferentRootDirAndWALRootDir() throws Exception {
  // Change wal root dir and reset the configuration
  Path walRootDir = UTIL.createWALRootDir();
  this.conf = HBaseConfiguration.create(UTIL.getConfiguration());

  FileSystem walFs = CommonFSUtils.getWALFileSystem(this.conf);
  this.oldLogDir = new Path(walRootDir, HConstants.HREGION_OLDLOGDIR_NAME);
  String serverName =
      ServerName.valueOf(TEST_NAME.getMethodName() + "-manual", 16010, System.currentTimeMillis())
          .toString();
  this.logName = AbstractFSWALProvider.getWALDirectoryName(serverName);
  this.logDir = new Path(walRootDir, logName);
  this.wals = new WALFactory(conf, TEST_NAME.getMethodName());

  Pair<TableDescriptor, RegionInfo> pair = setupTableAndRegion();
  TableDescriptor td = pair.getFirst();
  RegionInfo ri = pair.getSecond();

  WAL wal = createWAL(walFs, walRootDir, logName);
  HRegion region = HRegion.openHRegion(this.conf, this.fs, rootDir, ri, td, wal);
  writeData(td, region);

  // Now close the region without flush
  region.close(true);
  wal.shutdown();
  // split the log
  WALSplitter.split(walRootDir, logDir, oldLogDir, FileSystem.get(this.conf), this.conf, wals);

  WAL wal2 = createWAL(walFs, walRootDir, logName);
  HRegion region2 = HRegion.openHRegion(this.conf, this.fs, rootDir, ri, td, wal2);
  Result result2 = region2.get(new Get(ROW));
  assertEquals(td.getColumnFamilies().length, result2.size());
  for (ColumnFamilyDescriptor cfd : td.getColumnFamilies()) {
    assertTrue(Bytes.equals(VALUE1, result2.getValue(cfd.getName(), QUALIFIER)));
  }
}
 

private void compactTable(TableName tableName) throws IOException {
  for(JVMClusterUtil.RegionServerThread t : cluster.getRegionServerThreads()) {
    for(HRegion region : t.getRegionServer().getRegions(tableName)) {
      region.compact(true);
    }
  }
}
 

/**
 * @param region
 * @param table
 * @param collection
 */
public void addEdits(HRegion region, HTableInterfaceReference table,
    Collection<Mutation> collection) {
  Multimap<HTableInterfaceReference, Mutation> edits = cache.get(region);
  if (edits == null) {
    edits = ArrayListMultimap.<HTableInterfaceReference, Mutation> create();
    cache.put(region, edits);
  }
  edits.putAll(table, collection);
}
 

protected void startScannerThreads() throws InterruptedException {
  // Start parallel scan threads
  ScanThread[] scanThreads = new ScanThread[3];
  for (int i = 0; i < 3; i++) {
    scanThreads[i] = new ScanThread((HRegion) region);
  }
  for (ScanThread thread : scanThreads) {
    thread.start();
  }
  while (counter.get() != 3) {
    Thread.sleep(100);
  }
}
 

private static <T extends RegionObserver> T find(final TableName tableName,
        Class<T> clz) throws IOException, InterruptedException {
  HRegion region = find(tableName);
  Coprocessor cp = region.getCoprocessorHost().findCoprocessor(clz.getName());
  assertTrue("The cp instance should be " + clz.getName()
          + ", current instance is " + cp.getClass().getName(), clz.isInstance(cp));
  return clz.cast(cp);
}
 

HRegion reopenRegion(final HRegion closedRegion, Class<?> ... implClasses)
    throws IOException {
  //RegionInfo info = new RegionInfo(tableName, null, null, false);
  HRegion r = HRegion.openHRegion(closedRegion, null);

  // this following piece is a hack. currently a coprocessorHost
  // is secretly loaded at OpenRegionHandler. we don't really
  // start a region server here, so just manually create cphost
  // and set it to region.
  Configuration conf = TEST_UTIL.getConfiguration();
  RegionCoprocessorHost host = new RegionCoprocessorHost(r,
      Mockito.mock(RegionServerServices.class), conf);
  r.setCoprocessorHost(host);

  for (Class<?> implClass : implClasses) {
    host.load((Class<? extends RegionCoprocessor>) implClass, Coprocessor.PRIORITY_USER, conf);
  }
  // we need to manually call pre- and postOpen here since the
  // above load() is not the real case for CP loading. A CP is
  // expected to be loaded by default from 1) configuration; or 2)
  // HTableDescriptor. If it's loaded after HRegion initialized,
  // the pre- and postOpen() won't be triggered automatically.
  // Here we have to call pre and postOpen explicitly.
  host.preOpen();
  host.postOpen();
  return r;
}
 

/**
 * create a table with 5 regions, having region sizes so as to provoke a split
 * of the largest region.
 * <ul>
 *   <li>total table size: 12</li>
 *   <li>average region size: 2.4</li>
 *   <li>split threshold: 2.4 * 2 = 4.8</li>
 * </ul>
 */
private static int createTableBegsSplit(final TableName tableName,
    final boolean normalizerEnabled, final boolean isMergeEnabled)
  throws IOException {
  final List<HRegion> generatedRegions = generateTestData(tableName, 1, 1, 2, 3, 5);
  assertEquals(5, MetaTableAccessor.getRegionCount(TEST_UTIL.getConnection(), tableName));
  admin.flush(tableName);

  final TableDescriptor td = TableDescriptorBuilder.newBuilder(admin.getDescriptor(tableName))
    .setNormalizationEnabled(normalizerEnabled)
    .setMergeEnabled(isMergeEnabled)
    .build();
  admin.modifyTable(td);

  // make sure relatively accurate region statistics are available for the test table. use
  // the last/largest region as clue.
  TEST_UTIL.waitFor(TimeUnit.MINUTES.toMillis(1), new ExplainingPredicate<IOException>() {
    @Override public String explainFailure() {
      return "expected largest region to be >= 4mb.";
    }
    @Override public boolean evaluate() {
      return generatedRegions.stream()
        .mapToDouble(val -> getRegionSizeMB(master, val.getRegionInfo()))
        .allMatch(val -> val > 0)
        && getRegionSizeMB(master, generatedRegions.get(4).getRegionInfo()) >= 4.0;
    }
  });
  return 5;
}