c549afa1a9
In one of the next patches, we will want to use (in BTI partition index writer) the same hash as used by the bloom filter, and we'll also want to allow rebuilding the filter in a second pass (after the whole sstable is written) from hashes (as opposed to rebuilding from partition keys saved in Index.db, which is something we sometimes do today) saved to a temporary file. For those, we need an interface that allows us to compute the hash externally, and only pass the hash to `add()`.
99 lines
2.4 KiB
C++
99 lines
2.4 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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* This file contains code from a variety of .java files from the
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* Cassandra project, adapted to our needs.
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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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#pragma once
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#include "i_filter.hh"
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#include "utils/large_bitset.hh"
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namespace utils {
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namespace filter {
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class bloom_filter: public i_filter {
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public:
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using bitmap = large_bitset;
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private:
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bitmap _bitset;
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int _hash_count;
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filter_format _format;
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static thread_local struct stats {
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uint64_t memory_size = 0;
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} _shard_stats;
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stats& _stats = _shard_stats;
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public:
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int num_hashes() { return _hash_count; }
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bitmap& bits() { return _bitset; }
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bloom_filter(int hashes, bitmap&& bs, filter_format format) noexcept;
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~bloom_filter() noexcept;
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virtual void add(const bytes_view& key) override;
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virtual void add(const hashed_key& key) override;
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virtual bool is_present(const bytes_view& key) override;
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virtual bool is_present(hashed_key key) override;
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virtual void clear() override {
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_bitset.clear();
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}
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virtual void close() override { }
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virtual size_t memory_size() override {
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return sizeof(_hash_count) + _bitset.memory_size();
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}
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static const stats& get_shard_stats() noexcept {
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return _shard_stats;
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}
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};
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struct murmur3_bloom_filter: public bloom_filter {
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murmur3_bloom_filter(int hashes, bitmap&& bs, filter_format format)
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: bloom_filter(hashes, std::move(bs), format)
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{}
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};
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struct always_present_filter: public i_filter {
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virtual bool is_present(const bytes_view& key) override {
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return true;
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}
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virtual bool is_present(hashed_key key) override {
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return true;
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}
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virtual void add(const bytes_view& key) override { }
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virtual void add(const hashed_key& key) override { }
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virtual void clear() override { }
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virtual void close() override { }
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virtual size_t memory_size() override {
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return 0;
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}
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};
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// Get the size of the bitset (in bits, not bytes) for the specific parameters.
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size_t get_bitset_size(int64_t num_elements, int buckets_per);
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filter_ptr create_filter(int hash, large_bitset&& bitset, filter_format format);
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filter_ptr create_filter(int hash, int64_t num_elements, int buckets_per, filter_format format);
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}
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}
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