imay commented on a change in pull request #2471: add block split bloom filter URL: https://github.com/apache/incubator-doris/pull/2471#discussion_r358810224
########## File path: be/src/olap/rowset/segment_v2/bloom_filter.h ########## @@ -0,0 +1,167 @@ +// 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 <cstdint> +#include <functional> +#include <memory> + +#include "olap/utils.h" +#include "gen_cpp/segment_v2.pb.h" +#include "util/murmur_hash3.h" +#include "common/status.h" + +namespace doris { +namespace segment_v2 { + +struct BloomFilterOptions { + // false positive probablity + double fpp = 0.05; + HashStrategyPB strategy = HASH_MURMUR3_X64_64; +}; + +// Base class for bloom filter +// To support null value, the size of bloom filter is optimize bytes + 1. +// The last byte is for null value flag. +class BloomFilter { +public: + // Default seed for the hash function. It comes from date +%s. + static const uint32_t DEFAULT_SEED = 1575457558; + + // Minimum Bloom filter size, set to the size of a tiny Bloom filter block + static const uint32_t MINIMUM_BYTES = 32; + + // Maximum Bloom filter size, set it to half of max segment file size + static const uint32_t MAXIMUM_BYTES = 128 * 1024 * 1024; + + // Factory function for BloomFilter + static Status create(BloomFilterAlgorithmPB algorithm, std::unique_ptr<BloomFilter>* bf); + + BloomFilter() = default; + + virtual ~BloomFilter() { + delete[] _data; + } + + // for write + bool init(uint64_t n, double fpp, HashStrategyPB strategy) { + if (strategy == HASH_MURMUR3_X64_64) { + _hash_func = murmur_hash3_x64_64; + } else { + return false; + } + _num_bytes = _optimal_bit_num(n, fpp) / 8; + _size = _num_bytes + 1; + // reserve last byte for null flag + _data = new char[_size]; + _has_null = (bool*)(_data + _num_bytes); + *_has_null = false; + return true; + } + + // for read + // use deep copy to aquire the data + bool init(char* buf, uint32_t size, HashStrategyPB strategy) { + DCHECK(size > 1); + if (strategy == HASH_MURMUR3_X64_64) { + _hash_func = murmur_hash3_x64_64; + } else { + return false; + } + if (size == 0) { + return false; + } + _data = new char[size]; + memcpy(_data, buf, size); + _size = size; + _num_bytes = _size -1; + _has_null = (bool*)(_data + _num_bytes); + return true; + } + + void reset() { + memset(_data, 0, _size); + } + + uint64_t hash(char* buf, uint32_t size) const { + uint64_t hash_code; + _hash_func(buf, size, DEFAULT_SEED, &hash_code); + return hash_code; + } + + void add_bytes(char* buf, uint32_t size) { + if (buf == nullptr) { + *_has_null = true; + return; + } + uint64_t code = hash(buf, size); + add_hash(code); + } + + bool test_bytes(char* buf, uint32_t size) const { + if (buf == nullptr) { + return *_has_null; + } + uint64_t code = hash(buf, size); + return test_hash(code); + } + + char* data() const { return _data; } + + uint32_t num_bytes() const { return _num_bytes; } + + uint32_t size() const { return _size; } + + void set_has_null(bool has_null) { + *_has_null = has_null; + } + + bool has_null() const { + return *_has_null; + } + + virtual void add_hash(uint64_t hash) = 0; + virtual bool test_hash(uint64_t hash) const = 0; + +private: + // Compute the optimal bit number according to the following rule: + // m = -n * ln(fpp) / (ln(2) ^ 2) + // n: expected distinct record number + // fpp: false positive probablity + // the result will be power of 2 + uint32_t _optimal_bit_num(uint64_t n, double fpp); + +protected: + // bloom filter data + // specially add one byte for null flag + char* _data; + // optimal bloom filter num bytes + // it is calculated by optimal_bit_num() / 8 + uint32_t _num_bytes; + // equal to _num_bytes + 1 + // last byte is for has_null flag + uint32_t _size; + // last byte's pointer in data for null flag + bool* _has_null; Review comment: give default value for all these members. ---------------------------------------------------------------- This is an automated message from the Apache Git Service. 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