hash_partitioner_impl.hpp

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/*
 * Copyright (c) 2014-2015, Hewlett-Packard Development Company, LP.
 * This program is free software; you can redistribute it and/or modify it
 * under the terms of the GNU General Public License as published by the Free
 * Software Foundation; either version 2 of the License, or (at your option)
 * any later version.
 *
 * This program is distributed in the hope that it will be useful, but WITHOUT
 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for
 * more details. You should have received a copy of the GNU General Public
 * License along with this program; if not, write to the Free Software
 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
 *
 * HP designates this particular file as subject to the "Classpath" exception
 * as provided by HP in the LICENSE.txt file that accompanied this code.
 */
#ifndef FOEDUS_STORAGE_HASH_HASH_PARTITIONER_IMPL_HPP_
#define FOEDUS_STORAGE_HASH_HASH_PARTITIONER_IMPL_HPP_

#include <stdint.h>

#include <cstring>
#include <iosfwd>

#include "foedus/error_stack.hpp"
#include "foedus/fwd.hpp"
#include "foedus/memory/fwd.hpp"
#include "foedus/storage/partitioner.hpp"
#include "foedus/storage/storage_id.hpp"
#include "foedus/storage/hash/hash_id.hpp"

namespace foedus {
namespace storage {
namespace hash {
class HashPartitioner final {
 public:
  explicit HashPartitioner(Partitioner* parent);

  ErrorStack design_partition(const Partitioner::DesignPartitionArguments& args);
  void design_partition_task(uint16_t task);

  bool is_partitionable() const;
  void partition_batch(const Partitioner::PartitionBatchArguments& args) const;
  void sort_batch(const Partitioner::SortBatchArguments& args) const;

  const PartitionId* get_bucket_owners() const;

  friend std::ostream& operator<<(std::ostream& o, const HashPartitioner& v);

 private:
  void design_partition_task_recurse(
    const memory::GlobalVolatilePageResolver& resolver,
    const HashIntermediatePage* page);

  Engine* const               engine_;
  const StorageId             id_;
  PartitionerMetadata* const  metadata_;
  HashPartitionerData*        data_;
};

struct HashPartitionerData final {
  // only for reinterpret_cast
  HashPartitionerData() = delete;
  ~HashPartitionerData() = delete;

  static uint64_t object_size(uint16_t node_count, HashBin total_bin_count) {
    if (node_count <= 1U) {
      return 16;  // in this case we don't need bin_owners_
    } else {
      return total_bin_count + 16;
    }
  }
  uint64_t object_size() const {
    if (!partitionable_) {
      return 16;
    } else {
      return total_bin_count_ + 16;
    }
  }

  bool                  partitionable_;   // +1 -> 1
  uint8_t               levels_;          // +1 -> 2
  uint8_t               bin_bits_;        // +1 -> 3
  uint8_t               bin_shifts_;      // +1 -> 4
  char                  padding_[4];      // +4 -> 8

  HashBin               total_bin_count_;   // +8 -> 16

  PartitionId           bin_owners_[8];
};


}  // namespace hash
}  // namespace storage
}  // namespace foedus
#endif  // FOEDUS_STORAGE_HASH_HASH_PARTITIONER_IMPL_HPP_