f3eade2f62
Drop the AGPL license in favor of a source-available license. See the blog post [1] for details. [1] https://www.scylladb.com/2024/12/18/why-were-moving-to-a-source-available-license/
90 lines
2.6 KiB
C++
90 lines
2.6 KiB
C++
/*
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* Copyright (C) 2015-present ScyllaDB
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*
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* Modified by ScyllaDB
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*/
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/*
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* SPDX-License-Identifier: (LicenseRef-ScyllaDB-Source-Available-1.0 and Apache-2.0)
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*/
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#include "i_filter.hh"
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#include "bytes.hh"
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#include <seastar/core/shared_ptr.hh>
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#include <seastar/core/align.hh>
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#include <seastar/core/loop.hh>
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#include "utils/large_bitset.hh"
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#include <array>
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#include <cstdlib>
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#include "utils/bloom_calculations.hh"
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#include "bloom_filter.hh"
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namespace utils {
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namespace filter {
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thread_local bloom_filter::stats bloom_filter::_shard_stats;
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template<typename Func>
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void for_each_index(hashed_key hk, int count, int64_t max, filter_format format, Func&& func) {
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auto h = hk.hash();
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int64_t base = (format == filter_format::k_l_format) ? h[0] : h[1];
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int64_t inc = (format == filter_format::k_l_format) ? h[1] : h[0];
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for (int i = 0; i < count; i++) {
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if (func(std::abs(base % max)) == stop_iteration::yes) {
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break;
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}
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base = static_cast<int64_t>(static_cast<uint64_t>(base) + static_cast<uint64_t>(inc));
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}
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}
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bloom_filter::bloom_filter(int hashes, bitmap&& bs, filter_format format) noexcept
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: _bitset(std::move(bs))
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, _hash_count(hashes)
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, _format(format)
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{
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_stats.memory_size += memory_size();
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}
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bloom_filter::~bloom_filter() noexcept {
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_stats.memory_size -= memory_size();
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}
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bool bloom_filter::is_present(hashed_key key) {
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bool result = true;
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for_each_index(key, _hash_count, _bitset.size(), _format, [this, &result] (auto i) {
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if (!_bitset.test(i)) {
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result = false;
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return stop_iteration::yes;
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}
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return stop_iteration::no;
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});
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return result;
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}
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void bloom_filter::add(const bytes_view& key) {
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for_each_index(make_hashed_key(key), _hash_count, _bitset.size(), _format, [this] (auto i) {
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_bitset.set(i);
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return stop_iteration::no;
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});
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}
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bool bloom_filter::is_present(const bytes_view& key) {
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return is_present(make_hashed_key(key));
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}
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size_t get_bitset_size(int64_t num_elements, int buckets_per) {
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int64_t num_bits = (num_elements * buckets_per) + bloom_calculations::EXCESS;
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num_bits = align_up<int64_t>(num_bits, 64); // Seems to be implied in origin
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return num_bits;
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}
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filter_ptr create_filter(int hash, large_bitset&& bitset, filter_format format) {
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return std::make_unique<murmur3_bloom_filter>(hash, std::move(bitset), format);
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}
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filter_ptr create_filter(int hash, int64_t num_elements, int buckets_per, filter_format format) {
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return std::make_unique<murmur3_bloom_filter>(hash, large_bitset(get_bitset_size(num_elements, buckets_per)), format);
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}
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}
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}
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