Examples of org.apache.hadoop.hbase.io.hfile.HFileScanner

Package org.apache.hadoop.hbase.io.hfile

Examples of org.apache.hadoop.hbase.io.hfile.HFileScanner

org.apache.hadoop.hbase.io.hfile.HFileScanner
A scanner allows you to position yourself within a HFile and scan through it. It allows you to reposition yourself as well.
A scanner doesn't always have a key/value that it is pointing to when it is first created and before {@link #seekTo()}/ {@link #seekTo(byte[])} are called.In this case, {@link #getKey()}/ {@link #getValue()} returns null. At mostother times, a key and value will be available. The general pattern is that you position the Scanner using the seekTo variants and then getKey and getValue.

            + this.region);
      }


      if (verifyBulkLoads) {
        KeyValue prevKV = null;
        HFileScanner scanner = reader.getScanner(false, false, false);
        scanner.seekTo();
        do {
          KeyValue kv = scanner.getKeyValue();
          if (prevKV != null) {
            if (Bytes.compareTo(prevKV.getBuffer(), prevKV.getRowOffset(),
                prevKV.getRowLength(), kv.getBuffer(), kv.getRowOffset(),
                kv.getRowLength()) > 0) {
              throw new InvalidHFileException("Previous row is greater than"
                  + " current row: path=" + srcPath + " previous="
                  + Bytes.toStringBinary(prevKV.getKey()) + " current="
                  + Bytes.toStringBinary(kv.getKey()));
            }
            if (Bytes.compareTo(prevKV.getBuffer(), prevKV.getFamilyOffset(),
                prevKV.getFamilyLength(), kv.getBuffer(), kv.getFamilyOffset(),
                kv.getFamilyLength()) != 0) {
              throw new InvalidHFileException("Previous key had different"
                  + " family compared to current key: path=" + srcPath
                  + " previous=" + Bytes.toStringBinary(prevKV.getFamily())
                  + " current=" + Bytes.toStringBinary(kv.getFamily()));
            }
          }
          prevKV = kv;
        } while (scanner.next());
      }
    } finally {
      if (reader != null) reader.close();
    }
  }

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      // If the row we're looking for is past the end of file, set search key to
      // last key. TODO: Cache last and first key rather than make each time.
      firstOnRow = new KeyValue(lastKV.getRow(), HConstants.LATEST_TIMESTAMP);
    }
    // Get a scanner that caches blocks and that uses pread.
    HFileScanner scanner = r.getScanner(true, true, false);
    // Seek scanner.  If can't seek it, return.
    if (!seekToScanner(scanner, firstOnRow, firstKV)) return;
    // If we found candidate on firstOnRow, just return. THIS WILL NEVER HAPPEN!
    // Unlikely that there'll be an instance of actual first row in table.
    if (walkForwardInSingleRow(scanner, firstOnRow, state)) return;
    // If here, need to start backing up.
    while (scanner.seekBefore(firstOnRow.getBuffer(), firstOnRow.getKeyOffset(),
       firstOnRow.getKeyLength())) {
      KeyValue kv = scanner.getKeyValue();
      if (!state.isTargetTable(kv)) break;
      if (!state.isBetterCandidate(kv)) break;
      // Make new first on row.
      firstOnRow = new KeyValue(kv.getRow(), HConstants.LATEST_TIMESTAMP);
      // Seek scanner.  If can't seek it, break.

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      if (!state.isTargetTable(lastKV)) return;
      // If the row we're looking for is past the end of file, set search key to
      // last key. TODO: Cache last and first key rather than make each time.
      firstOnRow = new KeyValue(lastKV.getRow(), HConstants.LATEST_TIMESTAMP);
    }
    HFileScanner scanner = r.getScanner();
    // Seek scanner.  If can't seek it, return.
    if (!seekToScanner(scanner, firstOnRow, firstKV)) return;
    // If we found candidate on firstOnRow, just return. THIS WILL NEVER HAPPEN!
    // Unlikely that there'll be an instance of actual first row in table.
    if (walkForwardInSingleRow(scanner, firstOnRow, state)) return;
    // If here, need to start backing up.
    while (scanner.seekBefore(firstOnRow.getBuffer(), firstOnRow.getKeyOffset(),
       firstOnRow.getKeyLength())) {
      KeyValue kv = scanner.getKeyValue();
      if (!state.isTargetTable(kv)) break;
      if (!state.isBetterCandidate(kv)) break;
      // Make new first on row.
      firstOnRow = new KeyValue(kv.getRow(), HConstants.LATEST_TIMESTAMP);
      // Seek scanner.  If can't seek it, break.

View Full Code Here

  private int verifyHFile(Path p) throws IOException {
    Configuration conf = util.getConfiguration();
    HFile.Reader reader = HFile.createReader(
        p.getFileSystem(conf), p, new CacheConfig(conf), conf);
    reader.loadFileInfo();
    HFileScanner scanner = reader.getScanner(false, false);
    scanner.seekTo();
    int count = 0;
    do {
      count++;
    } while (scanner.next());
    assertTrue(count > 0);
    reader.close();
    return count;
  }

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              .withDataBlockEncoder(dataBlockEncoder)
              .withBloomType(bloomFilterType)
              .withChecksumType(Store.getChecksumType(conf))
              .withBytesPerChecksum(Store.getBytesPerChecksum(conf))
              .build();
      HFileScanner scanner = halfReader.getScanner(false, false, false);
      scanner.seekTo();
      do {
        KeyValue kv = scanner.getKeyValue();
        halfWriter.append(kv);
      } while (scanner.next());


      for (Map.Entry<byte[],byte[]> entry : fileInfo.entrySet()) {
        if (shouldCopyHFileMetaKey(entry.getKey())) {
          halfWriter.appendFileInfo(entry.getKey(), entry.getValue());
        }

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            + this.region);
      }


      if (verifyBulkLoads) {
        KeyValue prevKV = null;
        HFileScanner scanner = reader.getScanner(false, false, false);
        scanner.seekTo();
        do {
          KeyValue kv = scanner.getKeyValue();
          if (prevKV != null) {
            if (Bytes.compareTo(prevKV.getBuffer(), prevKV.getRowOffset(),
                prevKV.getRowLength(), kv.getBuffer(), kv.getRowOffset(),
                kv.getRowLength()) > 0) {
              throw new InvalidHFileException("Previous row is greater than"
                  + " current row: path=" + srcPath + " previous="
                  + Bytes.toStringBinary(prevKV.getKey()) + " current="
                  + Bytes.toStringBinary(kv.getKey()));
            }
            if (Bytes.compareTo(prevKV.getBuffer(), prevKV.getFamilyOffset(),
                prevKV.getFamilyLength(), kv.getBuffer(), kv.getFamilyOffset(),
                kv.getFamilyLength()) != 0) {
              throw new InvalidHFileException("Previous key had different"
                  + " family compared to current key: path=" + srcPath
                  + " previous=" + Bytes.toStringBinary(prevKV.getFamily())
                  + " current=" + Bytes.toStringBinary(kv.getFamily()));
            }
          }
          prevKV = kv;
        } while (scanner.next());
      }
    } finally {
      if (reader != null) reader.close();
    }
  }

View Full Code Here

      // If the row we're looking for is past the end of file, set search key to
      // last key. TODO: Cache last and first key rather than make each time.
      firstOnRow = new KeyValue(lastKV.getRow(), HConstants.LATEST_TIMESTAMP);
    }
    // Get a scanner that caches blocks and that uses pread.
    HFileScanner scanner = r.getHFileReader().getScanner(true, true, false);
    // Seek scanner.  If can't seek it, return.
    if (!seekToScanner(scanner, firstOnRow, firstKV)) return;
    // If we found candidate on firstOnRow, just return. THIS WILL NEVER HAPPEN!
    // Unlikely that there'll be an instance of actual first row in table.
    if (walkForwardInSingleRow(scanner, firstOnRow, state)) return;
    // If here, need to start backing up.
    while (scanner.seekBefore(firstOnRow.getBuffer(), firstOnRow.getKeyOffset(),
       firstOnRow.getKeyLength())) {
      KeyValue kv = scanner.getKeyValue();
      if (!state.isTargetTable(kv)) break;
      if (!state.isBetterCandidate(kv)) break;
      // Make new first on row.
      firstOnRow = new KeyValue(kv.getRow(), HConstants.LATEST_TIMESTAMP);
      // Seek scanner.  If can't seek it, break.

View Full Code Here

  }


  @Override
  public HFileScanner getScanner(final boolean cacheBlocks,
      final boolean pread, final boolean isCompaction) {
    final HFileScanner s = super.getScanner(cacheBlocks, pread, isCompaction);
    return new HFileScanner() {
      final HFileScanner delegate = s;
      public boolean atEnd = false;


      public ByteBuffer getKey() {
        if (atEnd) return null;

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  public byte[] getLastKey() {
    if (top) {
      return super.getLastKey();
    }
    // Get a scanner that caches the block and that uses pread.
    HFileScanner scanner = getScanner(true, true);
    try {
      if (scanner.seekBefore(this.splitkey)) {
        return Bytes.toBytes(scanner.getKey());
      }
    } catch (IOException e) {
      LOG.warn("Failed seekBefore " + Bytes.toStringBinary(this.splitkey), e);
    }
    return null;

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  }
  
  @Override
  public byte[] getFirstKey() {
    if (!firstKeySeeked) {
      HFileScanner scanner = getScanner(true, true, false);
      try {
        if (scanner.seekTo()) {
          this.firstKey = Bytes.toBytes(scanner.getKey());
        }
        firstKeySeeked = true;
      } catch (IOException e) {
        LOG.warn("Failed seekTo first KV in the file", e);
      }

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org.apache.hadoop.hbase.HFilePerformanceEvaluation$UniformRandomSmallScan

org.apache.hadoop.hbase.index.io.IndexHalfStoreFileReader

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org.apache.hadoop.hbase.io.HalfHFileReader

org.apache.hadoop.hbase.io.HalfStoreFileReader

org.apache.hadoop.hbase.io.TestHalfStoreFileReader

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