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7f71448388
Summary: This implements a cache friendly version of Cuckoo Hash in which, in case of collission, we try to insert in next few locations. The size of the neighborhood to check is taken as an input parameter in builder and stored in the table.
Test Plan:
make check all
cuckoo_table_{db,reader,builder}_test
Reviewers: sdong, ljin
Reviewed By: ljin
Subscribers: leveldb
Differential Revision: https://reviews.facebook.net/D22455
83 lines
2.6 KiB
C++
83 lines
2.6 KiB
C++
// Copyright (c) 2014, Facebook, Inc. All rights reserved.
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// This source code is licensed under the BSD-style license found in the
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// LICENSE file in the root directory of this source tree. An additional grant
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// of patent rights can be found in the PATENTS file in the same directory.
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//
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// Copyright (c) 2011 The LevelDB Authors. All rights reserved.
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// Use of this source code is governed by a BSD-style license that can be
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// found in the LICENSE file. See the AUTHORS file for names of contributors.
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#pragma once
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#ifndef ROCKSDB_LITE
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#include <string>
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#include <memory>
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#include <utility>
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#include <vector>
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#include "db/dbformat.h"
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#include "rocksdb/env.h"
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#include "table/table_reader.h"
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namespace rocksdb {
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class Arena;
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class TableReader;
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class CuckooTableReader: public TableReader {
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public:
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CuckooTableReader(
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const Options& options,
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std::unique_ptr<RandomAccessFile>&& file,
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uint64_t file_size,
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const Comparator* user_comparator,
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uint64_t (*get_slice_hash)(const Slice&, uint32_t, uint64_t));
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~CuckooTableReader() {}
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std::shared_ptr<const TableProperties> GetTableProperties() const override {
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return table_props_;
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}
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Status status() const { return status_; }
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Status Get(
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const ReadOptions& readOptions, const Slice& key, void* handle_context,
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bool (*result_handler)(void* arg, const ParsedInternalKey& k,
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const Slice& v),
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void (*mark_key_may_exist_handler)(void* handle_context) = nullptr)
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override;
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Iterator* NewIterator(const ReadOptions&, Arena* arena = nullptr) override;
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void Prepare(const Slice& target) override;
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// Report an approximation of how much memory has been used.
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size_t ApproximateMemoryUsage() const override;
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// Following methods are not implemented for Cuckoo Table Reader
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uint64_t ApproximateOffsetOf(const Slice& key) override { return 0; }
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void SetupForCompaction() override {}
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// End of methods not implemented.
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private:
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friend class CuckooTableIterator;
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void LoadAllKeys(std::vector<std::pair<Slice, uint32_t>>* key_to_bucket_id);
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std::unique_ptr<RandomAccessFile> file_;
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Slice file_data_;
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bool is_last_level_;
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std::shared_ptr<const TableProperties> table_props_;
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Status status_;
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uint32_t num_hash_func_;
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std::string unused_key_;
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uint32_t key_length_;
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uint32_t value_length_;
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uint32_t bucket_length_;
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uint32_t cuckoo_block_size_;
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uint32_t cuckoo_block_bytes_minus_one_;
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uint64_t hash_table_size_;
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const Comparator* ucomp_;
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uint64_t (*get_slice_hash_)(const Slice& s, uint32_t index,
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uint64_t max_num_buckets);
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};
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} // namespace rocksdb
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#endif // ROCKSDB_LITE
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