yiguolei commented on code in PR #13654: URL: https://github.com/apache/doris/pull/13654#discussion_r1021054030
########## be/src/vec/common/hash_table/partitioned_hash_table.h: ########## @@ -0,0 +1,412 @@ +// 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. +// This file is copied from +// https://github.com/ClickHouse/ClickHouse/blob/master/src/Common/HashTable/TwoLevelHashTable.h +// and modified by Doris +#pragma once + +#include "vec/common/hash_table/hash_table.h" + +/** Two-level hash table. + * Represents 256 (or 1ULL << BITS_FOR_BUCKET) small hash tables (buckets of the first level). + * To determine which one to use, one of the bytes of the hash function is taken. + * + * Usually works a little slower than a simple hash table. + * However, it has advantages in some cases: + * - if you need to merge two hash tables together, then you can easily parallelize it by buckets; + * - delay during resizes is amortized, since the small hash tables will be resized separately; + * - in theory, resizes are cache-local in a larger range of sizes. + */ + +template <size_t initial_size_degree = 8> +struct PartitionedHashTableGrower : public HashTableGrowerWithPrecalculation<initial_size_degree> { + /// Increase the size of the hash table. + void increase_size() { this->increase_size_degree(this->size_degree() >= 15 ? 1 : 2); } +}; + +template <typename Key, typename Cell, typename Hash, typename Grower, typename Allocator, + typename ImplTable = HashTable<Key, Cell, Hash, Grower, Allocator>, + size_t BITS_FOR_BUCKET = 4> +class PartitionedHashTable : private boost::noncopyable, + protected Hash /// empty base optimization +{ +protected: + friend class const_iterator; + friend class iterator; + + using HashValue = size_t; + using Self = PartitionedHashTable; + +public: + using Impl = ImplTable; + + static constexpr size_t NUM_BUCKETS = 1ULL << BITS_FOR_BUCKET; + static constexpr size_t MAX_BUCKET = NUM_BUCKETS - 1; + + //factor that will trigger growing the hash table on insert. + static constexpr float MAX_BUCKET_OCCUPANCY_FRACTION = 0.5f; + + size_t hash(const Key& x) const { return Hash::operator()(x); } + + /// NOTE Bad for hash tables with more than 2^32 cells. + static size_t getBucketFromHash(size_t hash_value) { + return (hash_value >> (32 - BITS_FOR_BUCKET)) & MAX_BUCKET; + } + + float get_factor() const { return MAX_BUCKET_OCCUPANCY_FRACTION; } + + bool should_be_shrink(int64_t valid_row) { return false; } + + void init_buf_size(size_t reserve_for_num_elements) {} + + void delete_zero_key(Key key) {} + + size_t get_buffer_size_in_bytes() const { + size_t buff_size = 0; + for (const auto& impl : impls) buff_size += impl.get_buffer_size_in_bytes(); + return buff_size; + } + + size_t get_buffer_size_in_cells() const { + size_t buff_size = 0; + for (const auto& impl : impls) buff_size += impl.get_buffer_size_in_cells(); + return buff_size; + } + + size_t* get_buffer_sizes_in_cells(size_t& num_buckets) const { + num_buckets = NUM_BUCKETS; + size_t* sizes = new size_t[NUM_BUCKETS]; + for (size_t i = 0; i < NUM_BUCKETS; ++i) { + sizes[i] = impls[i].get_buffer_size_in_cells(); + } + return sizes; + } + + void reset_resize_timer() { + for (auto& impl : impls) { + impl.reset_resize_timer(); + } + } + int64_t get_resize_timer_value() const { + int64_t resize_timer_ns = 0; + for (const auto& impl : impls) { + resize_timer_ns += impl.get_resize_timer_value(); + } + return resize_timer_ns; + } + +protected: + typename Impl::iterator beginOfNextNonEmptyBucket(size_t& bucket) { + while (bucket != NUM_BUCKETS && impls[bucket].empty()) ++bucket; + + if (bucket != NUM_BUCKETS) return impls[bucket].begin(); + + --bucket; + return impls[MAX_BUCKET].end(); + } + + typename Impl::const_iterator beginOfNextNonEmptyBucket(size_t& bucket) const { + while (bucket != NUM_BUCKETS && impls[bucket].empty()) ++bucket; + + if (bucket != NUM_BUCKETS) return impls[bucket].begin(); + + --bucket; + return impls[MAX_BUCKET].end(); + } + +public: + using key_type = typename Impl::key_type; + using mapped_type = typename Impl::mapped_type; + using value_type = typename Impl::value_type; + using cell_type = typename Impl::cell_type; + + using LookupResult = typename Impl::LookupResult; + using ConstLookupResult = typename Impl::ConstLookupResult; + + Impl impls[NUM_BUCKETS]; + + PartitionedHashTable() = default; + + explicit PartitionedHashTable(size_t size_hint) { + for (auto& impl : impls) impl.reserve(size_hint / NUM_BUCKETS); + } + + /// Copy the data from another (normal) hash table. It should have the same hash function. + template <typename Source> + explicit PartitionedHashTable(const Source& src) { + typename Source::const_iterator it = src.begin(); + + /// It is assumed that the zero key (stored separately) is first in iteration order. + if (it != src.end() && it.get_ptr()->is_zero(src)) { + insert(it->get_value()); + ++it; + } + + for (; it != src.end(); ++it) { + const Cell* cell = it.get_ptr(); + size_t hash_value = cell->get_hash(src); + size_t buck = getBucketFromHash(hash_value); + impls[buck].insert_unique_non_zero(cell, hash_value); + } + } + + PartitionedHashTable(PartitionedHashTable&& rhs) { + for (size_t i = 0; i < NUM_BUCKETS; ++i) { + impls[i] = std::move(rhs.impls[i]); + } + } + + PartitionedHashTable& operator=(PartitionedHashTable&& rhs) { + for (size_t i = 0; i < NUM_BUCKETS; ++i) { + impls[i] = std::move(rhs.impls[i]); + } + return *this; + } + + class iterator /// NOLINT + { + Self* container {}; + size_t bucket {}; + typename Impl::iterator current_it {}; + + friend class PartitionedHashTable; + + iterator(Self* container_, size_t bucket_, typename Impl::iterator current_it_) + : container(container_), bucket(bucket_), current_it(current_it_) {} + + public: + iterator() = default; + + bool operator==(const iterator& rhs) const { + return bucket == rhs.bucket && current_it == rhs.current_it; + } + bool operator!=(const iterator& rhs) const { return !(*this == rhs); } + + iterator& operator++() { + ++current_it; + if (current_it == container->impls[bucket].end()) { + ++bucket; + current_it = container->beginOfNextNonEmptyBucket(bucket); + } + + return *this; + } + + Cell& operator*() const { return *current_it; } + Cell* operator->() const { return current_it.get_ptr(); } + + Cell* get_ptr() const { return current_it.get_ptr(); } + size_t get_hash() const { return current_it.get_hash(); } + }; + + class const_iterator /// NOLINT + { + Self* container {}; + size_t bucket {}; + typename Impl::const_iterator current_it {}; + + friend class PartitionedHashTable; + + const_iterator(Self* container_, size_t bucket_, typename Impl::const_iterator current_it_) + : container(container_), bucket(bucket_), current_it(current_it_) {} + + public: + const_iterator() = default; + const_iterator(const iterator& rhs) + : container(rhs.container), + bucket(rhs.bucket), + current_it(rhs.current_it) {} /// NOLINT + + bool operator==(const const_iterator& rhs) const { + return bucket == rhs.bucket && current_it == rhs.current_it; + } + bool operator!=(const const_iterator& rhs) const { return !(*this == rhs); } + + const_iterator& operator++() { + ++current_it; + if (current_it == container->impls[bucket].end()) { + ++bucket; + current_it = container->beginOfNextNonEmptyBucket(bucket); + } + + return *this; + } + + const Cell& operator*() const { return *current_it; } + const Cell* operator->() const { return current_it->get_ptr(); } + + const Cell* get_ptr() const { return current_it.get_ptr(); } + size_t get_hash() const { return current_it.get_hash(); } + }; + + const_iterator begin() const { + size_t buck = 0; + typename Impl::const_iterator impl_it = beginOfNextNonEmptyBucket(buck); + return {this, buck, impl_it}; + } + + iterator begin() { + size_t buck = 0; + typename Impl::iterator impl_it = beginOfNextNonEmptyBucket(buck); + return {this, buck, impl_it}; + } + + const_iterator end() const { return {this, MAX_BUCKET, impls[MAX_BUCKET].end()}; } + iterator end() { return {this, MAX_BUCKET, impls[MAX_BUCKET].end()}; } + + void expanse_for_add_elem(size_t num_elem) { + size_t num_elem_per_bucket = (num_elem + NUM_BUCKETS - 1) / NUM_BUCKETS; + for (size_t i = 0; i < NUM_BUCKETS; ++i) impls[i].expanse_for_add_elem(num_elem_per_bucket); + } + + /// Insert a value. In the case of any more complex values, it is better to use the `emplace` function. + std::pair<LookupResult, bool> ALWAYS_INLINE insert(const value_type& x) { + size_t hash_value = hash(Cell::get_key(x)); + + std::pair<LookupResult, bool> res; + emplace(Cell::get_key(x), res.first, res.second, hash_value); + + if (res.second) insert_set_mapped(lookup_result_get_mapped(res.first), x); + + return res; + } + + template <typename KeyHolder> + void ALWAYS_INLINE prefetch(KeyHolder& key_holder) { + const auto& key = key_holder_get_key(key_holder); + const auto key_hash = hash(key); + const auto bucket = getBucketFromHash(key_hash); + impls[bucket].prefetch(key_holder); + } + + template <bool READ> + void ALWAYS_INLINE prefetch_by_hash(size_t hash_value) { + const auto bucket = getBucketFromHash(hash_value); + impls[bucket].template prefetch_by_hash<READ>(hash_value); + } + + template <bool READ, typename KeyHolder> + void ALWAYS_INLINE prefetch(KeyHolder& key_holder) { + const auto& key = key_holder_get_key(key_holder); + const auto key_hash = hash(key); + const auto bucket = getBucketFromHash(key_hash); + impls[bucket].template prefetch<READ>(key_holder); + } + + /** Insert the key, + * return an iterator to a position that can be used for `placement new` of value, + * as well as the flag - whether a new key was inserted. + * + * You have to make `placement new` values if you inserted a new key, + * since when destroying a hash table, the destructor will be invoked for it! + * + * Example usage: + * + * Map::iterator it; + * bool inserted; + * map.emplace(key, it, inserted); + * if (inserted) + * new(&it->second) Mapped(value); + */ + template <typename KeyHolder> + void ALWAYS_INLINE emplace(KeyHolder&& key_holder, LookupResult& it, bool& inserted) { + size_t hash_value = hash(key_holder_get_key(key_holder)); + emplace(key_holder, it, inserted, hash_value); + } + + /// Same, but with a precalculated values of hash function. + template <typename KeyHolder> + void ALWAYS_INLINE emplace(KeyHolder&& key_holder, LookupResult& it, bool& inserted, + size_t hash_value) { + size_t buck = getBucketFromHash(hash_value); + impls[buck].emplace(key_holder, it, inserted, hash_value); + } + + template <typename KeyHolder> + void ALWAYS_INLINE emplace(KeyHolder&& key_holder, LookupResult& it, size_t hash_value, + bool& inserted) { + emplace(key_holder, it, inserted, hash_value); + } + + LookupResult ALWAYS_INLINE find(Key x, size_t hash_value) { + size_t buck = getBucketFromHash(hash_value); + return impls[buck].find(x, hash_value); + } + + ConstLookupResult ALWAYS_INLINE find(Key x, size_t hash_value) const { + return const_cast<std::decay_t<decltype(*this)>*>(this)->find(x, hash_value); + } + + LookupResult ALWAYS_INLINE find(Key x) { return find(x, hash(x)); } + + ConstLookupResult ALWAYS_INLINE find(Key x) const { return find(x, hash(x)); } + + void write(doris::vectorized::BufferWritable& wb) const { + for (size_t i = 0; i < NUM_BUCKETS; ++i) impls[i].write(wb); + } + + /* + void writeText(DB::WriteBuffer & wb) const + { Review Comment: delete these code -- This is an automated message from the Apache Git Service. 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