rocksdb/table/cuckoo_table_factory.cc

// Copyright (c) 2014, Facebook, Inc. All rights reserved.
// This source code is licensed under the BSD-style license found in the
// LICENSE file in the root directory of this source tree. An additional grant
// of patent rights can be found in the PATENTS file in the same directory.

#ifndef ROCKSDB_LITE
#include "table/cuckoo_table_factory.h"

#include "db/dbformat.h"
#include "table/cuckoo_table_builder.h"
#include "table/cuckoo_table_reader.h"
#include "util/murmurhash.h"

namespace rocksdb {
extern const uint32_t kMaxNumHashTable = 64;

extern uint64_t GetSliceMurmurHash(const Slice& s, uint32_t index,
    uint64_t max_num_buckets) {
  static constexpr uint32_t seeds[kMaxNumHashTable] = {
    816922183, 506425713, 949485004, 22513986, 421427259, 500437285,
    888981693, 847587269, 511007211, 722295391, 934013645, 566947683,
    193618736, 428277388, 770956674, 819994962, 755946528, 40807421,
    263144466, 241420041, 444294464, 731606396, 304158902, 563235655,
    968740453, 336996831, 462831574, 407970157, 985877240, 637708754,
    736932700, 205026023, 755371467, 729648411, 807744117, 46482135,
    847092855, 620960699, 102476362, 314094354, 625838942, 550889395,
    639071379, 834567510, 397667304, 151945969, 443634243, 196618243,
    421986347, 407218337, 964502417, 327741231, 493359459, 452453139,
    692216398, 108161624, 816246924, 234779764, 618949448, 496133787,
    156374056, 316589799, 982915425, 553105889 };
  return MurmurHash(s.data(), s.size(), seeds[index]) % max_num_buckets;
}

Status CuckooTableFactory::NewTableReader(const Options& options,
    const EnvOptions& soptions, const InternalKeyComparator& icomp,
    std::unique_ptr<RandomAccessFile>&& file, uint64_t file_size,
    std::unique_ptr<TableReader>* table) const {
  std::unique_ptr<CuckooTableReader> new_reader(new CuckooTableReader(options,
      std::move(file), file_size, icomp.user_comparator(), GetSliceMurmurHash));
  Status s = new_reader->status();
  if (s.ok()) {
    *table = std::move(new_reader);
  }
  return s;
}

TableBuilder* CuckooTableFactory::NewTableBuilder(
    const Options& options, const InternalKeyComparator& internal_comparator,
    WritableFile* file, CompressionType compression_type) const {
  return new CuckooTableBuilder(file, hash_table_ratio_, kMaxNumHashTable,
      max_search_depth_, internal_comparator.user_comparator(),
      GetSliceMurmurHash);
}

std::string CuckooTableFactory::GetPrintableTableOptions() const {
  std::string ret;
  ret.reserve(2000);
  const int kBufferSize = 200;
  char buffer[kBufferSize];

  snprintf(buffer, kBufferSize, "  hash_table_ratio: %lf\n",
           hash_table_ratio_);
  ret.append(buffer);
  snprintf(buffer, kBufferSize, "  max_search_depth: %u\n",
           max_search_depth_);
  ret.append(buffer);
  return ret;
}

TableFactory* NewCuckooTableFactory(double hash_table_ratio,
    uint32_t max_search_depth) {
  return new CuckooTableFactory(hash_table_ratio, max_search_depth);
}

}  // namespace rocksdb
#endif  // ROCKSDB_LITE