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rocksdb/table/plain/plain_table_bloom.h

135 lines
4.1 KiB

// Copyright (c) 2011-present, Facebook, Inc. All rights reserved.
// This source code is licensed under both the GPLv2 (found in the
// COPYING file in the root directory) and Apache 2.0 License
// (found in the LICENSE.Apache file in the root directory).
#pragma once
#include <vector>
#include <string>
#include "rocksdb/slice.h"
#include "port/port.h"
#include "util/bloom_impl.h"
#include "util/hash.h"
#include "third-party/folly/folly/ConstexprMath.h"
#include <memory>
namespace rocksdb {
class Slice;
class Allocator;
class Logger;
// A legacy Bloom filter implementation used by Plain Table db format, for
// schema backward compatibility. Not for use in new filter applications.
class PlainTableBloomV1 {
public:
// allocator: pass allocator to bloom filter, hence trace the usage of memory
// total_bits: fixed total bits for the bloom
// num_probes: number of hash probes for a single key
// locality: If positive, optimize for cache line locality, 0 otherwise.
// hash_func: customized hash function
// huge_page_tlb_size: if >0, try to allocate bloom bytes from huge page TLB
// within this page size. Need to reserve huge pages for
// it to be allocated, like:
// sysctl -w vm.nr_hugepages=20
// See linux doc Documentation/vm/hugetlbpage.txt
explicit PlainTableBloomV1(uint32_t num_probes = 6);
void SetTotalBits(Allocator* allocator, uint32_t total_bits,
uint32_t locality, size_t huge_page_tlb_size,
Logger* logger);
~PlainTableBloomV1() {}
// Assuming single threaded access to this function.
void AddHash(uint32_t hash);
// Multithreaded access to this function is OK
bool MayContainHash(uint32_t hash) const;
void Prefetch(uint32_t hash);
uint32_t GetNumBlocks() const { return kNumBlocks; }
Slice GetRawData() const { return Slice(data_, GetTotalBits() / 8); }
void SetRawData(char* raw_data, uint32_t total_bits, uint32_t num_blocks = 0);
uint32_t GetTotalBits() const { return kTotalBits; }
bool IsInitialized() const { return kNumBlocks > 0 || kTotalBits > 0; }
private:
uint32_t kTotalBits;
uint32_t kNumBlocks;
const uint32_t kNumProbes;
char* data_;
static constexpr int LOG2_CACHE_LINE_SIZE =
folly::constexpr_log2(CACHE_LINE_SIZE);
};
#if defined(_MSC_VER)
#pragma warning(push)
// local variable is initialized but not referenced
#pragma warning(disable : 4189)
#endif
inline void PlainTableBloomV1::Prefetch(uint32_t h) {
if (kNumBlocks != 0) {
uint32_t ignored;
LegacyLocalityBloomImpl</*ExtraRotates*/ true>::PrepareHashMayMatch(
h, kNumBlocks, data_, &ignored, LOG2_CACHE_LINE_SIZE);
}
}
#if defined(_MSC_VER)
#pragma warning(pop)
#endif
inline bool PlainTableBloomV1::MayContainHash(uint32_t h) const {
assert(IsInitialized());
if (kNumBlocks != 0) {
return LegacyLocalityBloomImpl<true>::HashMayMatch(
h, kNumBlocks, kNumProbes, data_, LOG2_CACHE_LINE_SIZE);
} else {
return LegacyNoLocalityBloomImpl::HashMayMatch(h, kTotalBits, kNumProbes,
data_);
}
}
inline void PlainTableBloomV1::AddHash(uint32_t h) {
assert(IsInitialized());
if (kNumBlocks != 0) {
LegacyLocalityBloomImpl<true>::AddHash(h, kNumBlocks, kNumProbes, data_,
LOG2_CACHE_LINE_SIZE);
} else {
LegacyNoLocalityBloomImpl::AddHash(h, kTotalBits, kNumProbes, data_);
}
}
class BloomBlockBuilder {
public:
static const std::string kBloomBlock;
explicit BloomBlockBuilder(uint32_t num_probes = 6) : bloom_(num_probes) {}
void SetTotalBits(Allocator* allocator, uint32_t total_bits,
uint32_t locality, size_t huge_page_tlb_size,
Logger* logger) {
bloom_.SetTotalBits(allocator, total_bits, locality, huge_page_tlb_size,
logger);
}
uint32_t GetNumBlocks() const { return bloom_.GetNumBlocks(); }
void AddKeysHashes(const std::vector<uint32_t>& keys_hashes);
Slice Finish();
private:
PlainTableBloomV1 bloom_;
};
}; // namespace rocksdb