org.apache.hadoop.hbase.filter.KeyOnlyFilter Java Examples

@Override
public void run() {
    try (HTableInterface table = connection.getTable(tableName.getBytes())) {
        // Do not use Get not to increase read request count metric.
        // Use Scan.
        Scan scan = new Scan("".getBytes(), "".getBytes());
        FilterList filterList = new FilterList();
        filterList.addFilter(new KeyOnlyFilter());
        filterList.addFilter(new FirstKeyOnlyFilter());
        scan.setFilter(filterList);
        //noinspection EmptyTryBlock
        try(ResultScanner ignored = table.getScanner(scan)) {
        }
        return;
    } catch (IOException ignore) {
    }

    clean(tableName);
}
 

private Result getByScan(String path, byte[] family, byte[] column) throws IOException {
    byte[] startRow = Bytes.toBytes(path);
    byte[] endRow = plusZero(startRow);

    Scan scan = new Scan(startRow, endRow);
    if (family == null || column == null) {
        scan.setFilter(new KeyOnlyFilter());
    } else {
        scan.addColumn(family, column);
    }

    HTableInterface table = getConnection().getTable(getAllInOneTableName());
    try {
        ResultScanner scanner = table.getScanner(scan);
        Result result = null;
        for (Result r : scanner) {
            result = r;
        }
        return result == null || result.isEmpty() ? null : result;
    } finally {
        IOUtils.closeQuietly(table);
    }
}
 

@Override
protected boolean doAction() throws Exception {
  ResultScanner rs = null;
  try {
    Scan s = new Scan();
    s.setBatch(2);
    s.addFamily(FAMILY);
    s.setFilter(new KeyOnlyFilter());
    s.readVersions(1);

    rs = table.getScanner(s);
    Result result = rs.next();
    return result != null && result.size() > 0;
  } finally {
    if (rs != null) {
      rs.close();
    }
  }
}
 

public static boolean isReallyEmptyRegion(HConnection connection,
    String tableName, HRegionInfo regionInfo) throws IOException {
    boolean emptyRegion = false;
    // verify really empty region by scanning records
    try (HTableInterface table = connection.getTable(tableName)) {
        Scan scan = new Scan(regionInfo.getStartKey(), regionInfo.getEndKey());
        FilterList filterList = new FilterList();
        filterList.addFilter(new KeyOnlyFilter());
        filterList.addFilter(new FirstKeyOnlyFilter());
        scan.setFilter(filterList);
        scan.setCacheBlocks(false);
        scan.setSmall(true);
        scan.setCaching(1);

        try (ResultScanner scanner = table.getScanner(scan)) {
            if (scanner.next() == null) emptyRegion = true;
        }
    }
    return emptyRegion;
}
 

@Override
public void run() {
    try (HTableInterface table = connection.getTable(tableName.getBytes())) {
        // Do not use Get not to increase read request count metric.
        // Use Scan.
        Scan scan = new Scan("".getBytes(), "".getBytes());
        FilterList filterList = new FilterList();
        filterList.addFilter(new KeyOnlyFilter());
        filterList.addFilter(new FirstKeyOnlyFilter());
        scan.setFilter(filterList);
        //noinspection EmptyTryBlock
        try(ResultScanner ignored = table.getScanner(scan)) {
        }
        return;
    } catch (IOException ignore) {
    }

    clean(tableName);
}
 

public static boolean isReallyEmptyRegion(HConnection connection,
    String tableName, HRegionInfo regionInfo) throws IOException {
    boolean emptyRegion = false;
    // verify really empty region by scanning records
    try (HTableInterface table = connection.getTable(tableName)) {
        Scan scan = new Scan(regionInfo.getStartKey(), regionInfo.getEndKey());
        FilterList filterList = new FilterList();
        filterList.addFilter(new KeyOnlyFilter());
        filterList.addFilter(new FirstKeyOnlyFilter());
        scan.setFilter(filterList);
        scan.setCacheBlocks(false);
        scan.setSmall(true);
        scan.setCaching(1);

        try (ResultScanner scanner = table.getScanner(scan)) {
            if (scanner.next() == null) emptyRegion = true;
        }
    }
    return emptyRegion;
}
 

@Override
public void run() {
    try (HTableInterface table = connection.getTable(tableName.getBytes())) {
        // Do not use Get not to increase read request count metric.
        // Use Scan.
        Scan scan = new Scan("".getBytes(), "".getBytes());
        FilterList filterList = new FilterList();
        filterList.addFilter(new KeyOnlyFilter());
        filterList.addFilter(new FirstKeyOnlyFilter());
        scan.setFilter(filterList);
        //noinspection EmptyTryBlock
        try(ResultScanner ignored = table.getScanner(scan)) {
        }
        return;
    } catch (IOException ignore) {
    }

    clean(tableName);
}
 

public static boolean isReallyEmptyRegion(HConnection connection,
    String tableName, HRegionInfo regionInfo) throws IOException {
    boolean emptyRegion = false;
    // verify really empty region by scanning records
    try (HTableInterface table = connection.getTable(tableName)) {
        Scan scan = new Scan(regionInfo.getStartKey(), regionInfo.getEndKey());
        FilterList filterList = new FilterList();
        filterList.addFilter(new KeyOnlyFilter());
        filterList.addFilter(new FirstKeyOnlyFilter());
        scan.setFilter(filterList);
        scan.setCacheBlocks(false);
        scan.setSmall(true);
        scan.setCaching(1);

        try (ResultScanner scanner = table.getScanner(scan)) {
            if (scanner.next() == null) emptyRegion = true;
        }
    }
    return emptyRegion;
}
 

@Override
public void run() {
    try (HTableInterface table = connection.getTable(tableName.getBytes())) {
        // Do not use Get not to increase read request count metric.
        // Use Scan.
        Scan scan = new Scan("".getBytes(), "".getBytes());
        FilterList filterList = new FilterList();
        filterList.addFilter(new KeyOnlyFilter());
        filterList.addFilter(new FirstKeyOnlyFilter());
        scan.setFilter(filterList);
        //noinspection EmptyTryBlock
        try(ResultScanner ignored = table.getScanner(scan)) {
        }
        return;
    } catch (IOException ignore) {
    }

    clean(tableName);
}
 

public static boolean isReallyEmptyRegion(HConnection connection,
    String tableName, HRegionInfo regionInfo) throws IOException {
    boolean emptyRegion = false;
    // verify really empty region by scanning records
    try (HTableInterface table = connection.getTable(tableName)) {
        Scan scan = new Scan(regionInfo.getStartKey(), regionInfo.getEndKey());
        FilterList filterList = new FilterList();
        filterList.addFilter(new KeyOnlyFilter());
        filterList.addFilter(new FirstKeyOnlyFilter());
        scan.setFilter(filterList);
        scan.setCacheBlocks(false);
        scan.setSmall(true);
        scan.setCaching(1);

        try (ResultScanner scanner = table.getScanner(scan)) {
            if (scanner.next() == null) emptyRegion = true;
        }
    }
    return emptyRegion;
}
 

private static void prepareData(Connection conn) throws IOException {
    Table table = conn.getTable(TableName.valueOf(TEST_TABLE));

    try {
        // check how many rows existing
        int nRows = 0;
        Scan scan = new Scan();
        scan.setFilter(new KeyOnlyFilter());
        ResultScanner scanner = table.getScanner(scan);
        for (Result r : scanner) {
            r.getRow(); // nothing to do
            nRows++;
        }

        if (nRows > 0) {
            logger.info("{} existing rows", nRows);
            if (nRows != N_ROWS)
                throw new IOException("Expect " + N_ROWS + " rows but it is not");
            return;
        }

        // insert rows into empty table
        logger.info("Writing {} rows to {}", N_ROWS, TEST_TABLE);
        long nBytes = 0;
        for (int i = 0; i < N_ROWS; i++) {
            byte[] rowkey = Bytes.toBytes(i);
            Put put = new Put(rowkey);
            byte[] cell = randomBytes();
            put.addColumn(CF, QN, cell);
            table.put(put);
            nBytes += cell.length;
            dot(i, N_ROWS);
        }
        logger.info("Written {} rows, {} bytes", N_ROWS, nBytes);

    } finally {
        IOUtils.closeQuietly(table);
    }

}
 

private static void prepareData(Connection conn) throws IOException {
    Table table = conn.getTable(TableName.valueOf(TEST_TABLE));

    try {
        // check how many rows existing
        int nRows = 0;
        Scan scan = new Scan();
        scan.setFilter(new KeyOnlyFilter());
        ResultScanner scanner = table.getScanner(scan);
        for (Result r : scanner) {
            r.getRow(); // nothing to do
            nRows++;
        }

        if (nRows > 0) {
            logger.info("{} existing rows", nRows);
            if (nRows != N_ROWS)
                throw new IOException("Expect " + N_ROWS + " rows but it is not");
            return;
        }

        // insert rows into empty table
        logger.info("Writing {} rows to {}", N_ROWS, TEST_TABLE);
        long nBytes = 0;
        for (int i = 0; i < N_ROWS; i++) {
            byte[] rowkey = Bytes.toBytes(i);
            Put put = new Put(rowkey);
            byte[] cell = randomBytes();
            put.addColumn(CF, QN, cell);
            table.put(put);
            nBytes += cell.length;
            dot(i, N_ROWS);
        }
        logger.info("Written {} rows, {} bytes", N_ROWS, nBytes);

    } finally {
        IOUtils.closeQuietly(table);
    }

}
 

@Test
public void testKeyOnlyFilterWithReverseScan() throws Exception {
  final TableName tableName = name.getTableName();
  try (Table ht = TEST_UTIL.createTable(tableName, FAMILY)) {
    byte[][] ROWS = makeN(ROW, 10);
    byte[][] QUALIFIERS = {Bytes.toBytes("col0-<d2v1>-<d3v2>"),
            Bytes.toBytes("col1-<d2v1>-<d3v2>"),
            Bytes.toBytes("col2-<d2v1>-<d3v2>"),
            Bytes.toBytes("col3-<d2v1>-<d3v2>"),
            Bytes.toBytes("col4-<d2v1>-<d3v2>"),
            Bytes.toBytes("col5-<d2v1>-<d3v2>"),
            Bytes.toBytes("col6-<d2v1>-<d3v2>"),
            Bytes.toBytes("col7-<d2v1>-<d3v2>"),
            Bytes.toBytes("col8-<d2v1>-<d3v2>"),
            Bytes.toBytes("col9-<d2v1>-<d3v2>")};
    for (int i = 0; i < 10; i++) {
      Put put = new Put(ROWS[i]);
      put.addColumn(FAMILY, QUALIFIERS[i], VALUE);
      ht.put(put);
    }
    Scan scan = new Scan();
    scan.setReversed(true);
    scan.addFamily(FAMILY);
    Filter filter = new KeyOnlyFilter(true);
    scan.setFilter(filter);
    try (ResultScanner ignored = ht.getScanner(scan)) {
      int count = 0;
      for (Result result : ht.getScanner(scan)) {
        assertEquals(1, result.size());
        assertEquals(Bytes.SIZEOF_INT, result.rawCells()[0].getValueLength());
        assertEquals(VALUE.length, Bytes.toInt(CellUtil.cloneValue(result.rawCells()[0])));
        count++;
      }
      assertEquals(10, count);
    }
  }
}
 

@Test public void testKeyOnlyFilter() throws Exception {
  final TableName tableName = name.getTableName();
  try (Table ht = TEST_UTIL.createTable(tableName, FAMILY)) {
    byte[][] ROWS = makeN(ROW, 10);
    byte[][] QUALIFIERS =
      { Bytes.toBytes("col0-<d2v1>-<d3v2>"), Bytes.toBytes("col1-<d2v1>-<d3v2>"),
        Bytes.toBytes("col2-<d2v1>-<d3v2>"), Bytes.toBytes("col3-<d2v1>-<d3v2>"),
        Bytes.toBytes("col4-<d2v1>-<d3v2>"), Bytes.toBytes("col5-<d2v1>-<d3v2>"),
        Bytes.toBytes("col6-<d2v1>-<d3v2>"), Bytes.toBytes("col7-<d2v1>-<d3v2>"),
        Bytes.toBytes("col8-<d2v1>-<d3v2>"), Bytes.toBytes("col9-<d2v1>-<d3v2>") };
    for (int i = 0; i < 10; i++) {
      Put put = new Put(ROWS[i]);
      put.setDurability(Durability.SKIP_WAL);
      put.addColumn(FAMILY, QUALIFIERS[i], VALUE);
      ht.put(put);
    }
    Scan scan = new Scan();
    scan.addFamily(FAMILY);
    Filter filter = new KeyOnlyFilter(true);
    scan.setFilter(filter);
    try (ResultScanner scanner = ht.getScanner(scan)) {
      int count = 0;
      for (Result result : scanner) {
        assertEquals(1, result.size());
        assertEquals(Bytes.SIZEOF_INT, result.rawCells()[0].getValueLength());
        assertEquals(VALUE.length, Bytes.toInt(CellUtil.cloneValue(result.rawCells()[0])));
        count++;
      }
      assertEquals(10, count);
    }
  }
}
 

@ProcessElement
public void processElement(ProcessContext c) throws IOException {
  Scan scan = new Scan()
      .setRowPrefixFilter(c.element().getBytes())
      .setFilter(new KeyOnlyFilter());

  Table table = getConnection().getTable(TableName.valueOf(tableId));

  for (Result result : table.getScanner(scan)) {
    c.output(result.getRow());
  }
}
 

@Override
public Boolean call() throws Exception {

  // total length in bytes of all read rows.
  int result = 0;

  // Number of rows the scan will read before being considered done.
  int toRead = 100;
  try (Table t = connection.getTable(tableName)) {
    byte[] rk = Bytes.toBytes(ThreadLocalRandom.current().nextLong());
    Scan s = new Scan().withStartRow(rk);

    // This filter will keep the values from being sent accross the wire.
    // This is good for counting or other scans that are checking for
    // existence and don't rely on the value.
    s.setFilter(new KeyOnlyFilter());

    // Don't go back to the server for every single row.
    // We know these rows are small. So ask for 20 at a time.
    // This would be application specific.
    //
    // The goal is to reduce round trips but asking for too
    // many rows can lead to GC problems on client and server sides.
    s.setCaching(20);

    // Don't use the cache. While this is a silly test program it's still good to be
    // explicit that scans normally don't use the block cache.
    s.setCacheBlocks(false);

    // Open up the scanner and close it automatically when done.
    try (ResultScanner rs = t.getScanner(s)) {

      // Now go through rows.
      for (Result r : rs) {
        // Keep track of things size to simulate doing some real work.
        result += r.getRow().length;
        toRead -= 1;

        // Most online applications won't be
        // reading the entire table so this break
        // simulates small to medium size scans,
        // without needing to know an end row.
        if (toRead <= 0)  {
          break;
        }
      }
    }
  }
  return result > 0;
}
 

private static void prepareData(HConnection conn) throws IOException {
    HTableInterface table = conn.getTable(TEST_TABLE);

    try {
        // check how many rows existing
        int nRows = 0;
        Scan scan = new Scan();
        scan.setFilter(new KeyOnlyFilter());
        ResultScanner scanner = table.getScanner(scan);
        for (Result r : scanner) {
            r.getRow(); // nothing to do
            nRows++;
        }

        if (nRows > 0) {
            System.out.println(nRows + " existing rows");
            if (nRows != N_ROWS)
                throw new IOException("Expect " + N_ROWS + " rows but it is not");
            return;
        }

        // insert rows into empty table
        System.out.println("Writing " + N_ROWS + " rows to " + TEST_TABLE);
        long nBytes = 0;
        for (int i = 0; i < N_ROWS; i++) {
            byte[] rowkey = Bytes.toBytes(i);
            Put put = new Put(rowkey);
            byte[] cell = randomBytes();
            put.add(CF, QN, cell);
            table.put(put);
            nBytes += cell.length;
            dot(i, N_ROWS);
        }
        System.out.println();
        System.out.println("Written " + N_ROWS + " rows, " + nBytes + " bytes");

    } finally {
        IOUtils.closeQuietly(table);
    }

}
 

@ProcessElement
public void processElement(PipelineOptions po) {
  // Determine which column will be drawn based on runtime of job.
  long timestampDiff = System.currentTimeMillis() - START_TIME;
  long minutes = (timestampDiff / 1000) / 60;
  int timeOffsetIndex = Math.toIntExact(minutes / KEY_VIZ_WINDOW_MINUTES);

  ReadDataOptions options = po.as(ReadDataOptions.class);
  long count = 0;

  List<RowRange> ranges = getRangesForTimeIndex(timeOffsetIndex, getNumRows(options));
  if (ranges.size() == 0) {
    return;
  }

  try {
    // Scan with a filter that will only return the first key from each row. This filter is used
    // to more efficiently perform row count operations.
    Filter rangeFilters = new MultiRowRangeFilter(ranges);
    FilterList firstKeyFilterWithRanges = new FilterList(
        rangeFilters,
        new FirstKeyOnlyFilter(),
        new KeyOnlyFilter());
    Scan scan =
        new Scan()
            .addFamily(Bytes.toBytes(COLUMN_FAMILY))
            .setFilter(firstKeyFilterWithRanges);

    Table table = getConnection().getTable(TableName.valueOf(options.getBigtableTableId()));
    ResultScanner imageData = table.getScanner(scan);

    // Iterate over stream of rows to count them.
    for (Result row : imageData) {
      count++;
    }
  } catch (Exception e) {
    System.out.println("Error reading.");
    e.printStackTrace();
  }
  System.out.printf("got %d rows\n", count);
}