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doris/be/src/util/quantile_state.h
hongbin e61d296486 [Refactor] Replace '#ifndef' with '#pragma once' (#9456)
* Replace '#ifndef' with '#pragma once'
2022-05-10 09:25:59 +08:00

70 lines
2.1 KiB
C++

// Licensed to the Apache Software Foundation (ASF) under one
// or more contributor license agreements. See the NOTICE file
// distributed with this work for additional information
// regarding copyright ownership. The ASF licenses this file
// to you under the Apache License, Version 2.0 (the
// "License"); you may not use this file except in compliance
// with the License. You may obtain a copy of the License at
//
// http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing,
// software distributed under the License is distributed on an
// "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
// KIND, either express or implied. See the License for the
// specific language governing permissions and limitations
// under the License.
#pragma once
#include <memory>
#include <string>
#include <vector>
#include "slice.h"
#include "tdigest.h"
namespace doris {
struct Slice;
class TDigest;
const static int QUANTILE_STATE_EXPLICIT_NUM = 2048;
const static int QUANTILE_STATE_COMPRESSION_MIN = 2048;
const static int QUANTILE_STATE_COMPRESSION_MAX = 10000;
enum QuantileStateType {
EMPTY = 0,
SINGLE = 1, // single element
EXPLICIT = 2, // more than one elements,stored in vector
TDIGEST = 3 // TDIGEST object
};
template <typename T>
class QuantileState {
public:
QuantileState();
explicit QuantileState(float compression);
explicit QuantileState(const Slice& slice);
void set_compression(float compression);
bool deserialize(const Slice& slice);
size_t serialize(uint8_t* dst) const;
void merge(QuantileState<T>& other);
void add_value(const T& value);
void clear();
bool is_valid(const Slice& slice);
size_t get_serialized_size();
T get_value_by_percentile(float percentile);
T get_explicit_value_by_percentile(float percentile);
~QuantileState() = default;
private:
QuantileStateType _type = EMPTY;
std::unique_ptr<TDigest> _tdigest_ptr;
T _single_data;
std::vector<T> _explicit_data;
float _compression;
};
} // namespace doris