Exemple #1
0
  public static QuantileDigest merge(List<QuantileDigest> digests) {
    if (digests.isEmpty()) {
      throw new RuntimeException("Digests to be unioned should not be empty!");
    }

    QuantileDigest ret = digests.get(0);

    for (int i = 1; i < digests.size(); i++) {
      ret.merge(digests.get(i));
    }

    return ret;
  }
Exemple #2
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  private void rescaleToCommonLandmark(QuantileDigest one, QuantileDigest two) {
    long nowInSeconds = TimeUnit.NANOSECONDS.toSeconds(ticker.read());

    // 1. rescale this and other to common landmark
    long targetLandmark = Math.max(one.landmarkInSeconds, two.landmarkInSeconds);

    if (nowInSeconds - targetLandmark >= RESCALE_THRESHOLD_SECONDS) {
      targetLandmark = nowInSeconds;
    }

    if (targetLandmark != one.landmarkInSeconds) {
      one.rescale(targetLandmark);
    }

    if (targetLandmark != two.landmarkInSeconds) {
      two.rescale(targetLandmark);
    }
  }
Exemple #3
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  public static QuantileDigest deserialize(DataInput input) {
    try {
      double maxError = input.readDouble();
      double alpha = input.readDouble();

      QuantileDigest result = new QuantileDigest(maxError, alpha);

      result.landmarkInSeconds = input.readLong();
      result.min = input.readLong();
      result.max = input.readLong();
      result.totalNodeCount = input.readInt();

      Deque<Node> stack = new ArrayDeque<>();
      for (int i = 0; i < result.totalNodeCount; i++) {
        int flags = input.readByte();

        Node node = deserializeNode(input);

        if ((flags & Flags.HAS_RIGHT) != 0) {
          node.right = stack.pop();
        }

        if ((flags & Flags.HAS_LEFT) != 0) {
          node.left = stack.pop();
        }

        stack.push(node);
        result.weightedCount += node.weightedCount;
        if (node.weightedCount >= ZERO_WEIGHT_THRESHOLD) {
          result.nonZeroNodeCount++;
        }
      }

      if (!stack.isEmpty()) {
        Preconditions.checkArgument(
            stack.size() == 1, "Tree is corrupted. Expected a single root node");
        result.root = stack.pop();
      }

      return result;
    } catch (IOException e) {
      throw Throwables.propagate(e);
    }
  }
Exemple #4
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 public static QuantileDigest build(DataInput buf) throws IOException {
   return QuantileDigest.deserialize(buf);
 }
Exemple #5
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 @Override
 public void writeExternal(ObjectOutput out) throws IOException {
   holder.writeBytes(out);
 }
Exemple #6
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 public QuantileDigest(QuantileDigest quantileDigest) {
   this(quantileDigest.getMaxError(), quantileDigest.getAlpha());
   merge(quantileDigest);
 }