fork of https://github.com/rust-rocksdb/rust-rocksdb for nextgraph
You can not select more than 25 topics
Topics must start with a letter or number, can include dashes ('-') and can be up to 35 characters long.
81 lines
2.6 KiB
81 lines
2.6 KiB
1 year ago
|
// 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 <string>
|
||
|
|
|
||
|
|
#include "rocksdb/options.h"
|
||
|
|
#include "rocksdb/table.h"
|
||
|
|
#include "util/murmurhash.h"
|
||
|
|
|
||
|
|
namespace ROCKSDB_NAMESPACE {
|
||
|
|
|
||
|
|
const uint32_t kCuckooMurmurSeedMultiplier = 816922183;
|
||
|
|
static inline uint64_t CuckooHash(
|
||
|
|
const Slice& user_key, uint32_t hash_cnt, bool use_module_hash,
|
||
|
|
uint64_t table_size_, bool identity_as_first_hash,
|
||
|
|
uint64_t (*get_slice_hash)(const Slice&, uint32_t, uint64_t)) {
|
||
|
|
#if !defined NDEBUG || defined OS_WIN
|
||
|
|
// This part is used only in unit tests but we have to keep it for Windows
|
||
|
|
// build as we run test in both debug and release modes under Windows.
|
||
|
|
if (get_slice_hash != nullptr) {
|
||
|
|
return get_slice_hash(user_key, hash_cnt, table_size_);
|
||
|
|
}
|
||
|
|
#else
|
||
|
|
(void)get_slice_hash;
|
||
|
|
#endif
|
||
|
|
|
||
|
|
uint64_t value = 0;
|
||
|
|
if (hash_cnt == 0 && identity_as_first_hash) {
|
||
|
|
value = (*reinterpret_cast<const int64_t*>(user_key.data()));
|
||
|
|
} else {
|
||
|
|
value = MurmurHash(user_key.data(), static_cast<int>(user_key.size()),
|
||
|
|
kCuckooMurmurSeedMultiplier * hash_cnt);
|
||
|
|
}
|
||
|
|
if (use_module_hash) {
|
||
|
|
return value % table_size_;
|
||
|
|
} else {
|
||
|
|
return value & (table_size_ - 1);
|
||
|
|
}
|
||
|
|
}
|
||
|
|
|
||
|
|
// Cuckoo Table is designed for applications that require fast point lookups
|
||
|
|
// but not fast range scans.
|
||
|
|
//
|
||
|
|
// Some assumptions:
|
||
|
|
// - Key length and Value length are fixed.
|
||
|
|
// - Does not support Snapshot.
|
||
|
|
// - Does not support Merge operations.
|
||
|
|
// - Does not support prefix bloom filters.
|
||
|
|
class CuckooTableFactory : public TableFactory {
|
||
|
|
public:
|
||
|
|
explicit CuckooTableFactory(
|
||
|
|
const CuckooTableOptions& table_option = CuckooTableOptions());
|
||
|
|
~CuckooTableFactory() {}
|
||
|
|
|
||
|
|
// Method to allow CheckedCast to work for this class
|
||
|
|
static const char* kClassName() { return kCuckooTableName(); }
|
||
|
|
const char* Name() const override { return kCuckooTableName(); }
|
||
|
|
|
||
|
|
using TableFactory::NewTableReader;
|
||
|
|
Status NewTableReader(
|
||
|
|
const ReadOptions& ro, const TableReaderOptions& table_reader_options,
|
||
|
|
std::unique_ptr<RandomAccessFileReader>&& file, uint64_t file_size,
|
||
|
|
std::unique_ptr<TableReader>* table,
|
||
|
|
bool prefetch_index_and_filter_in_cache = true) const override;
|
||
|
|
|
||
|
|
TableBuilder* NewTableBuilder(
|
||
|
|
const TableBuilderOptions& table_builder_options,
|
||
|
|
WritableFileWriter* file) const override;
|
||
|
|
|
||
|
|
std::string GetPrintableOptions() const override;
|
||
|
|
|
||
|
|
private:
|
||
|
|
CuckooTableOptions table_options_;
|
||
|
|
};
|
||
|
|
|
||
|
|
} // namespace ROCKSDB_NAMESPACE
|