masstree_metadata.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_MASSTREE_MASSTREE_METADATA_HPP_
#define FOEDUS_STORAGE_MASSTREE_MASSTREE_METADATA_HPP_
#include <stdint.h>

#include <iosfwd>
#include <string>

#include "foedus/cxx11.hpp"
#include "foedus/error_stack.hpp"
#include "foedus/externalize/externalizable.hpp"
#include "foedus/storage/metadata.hpp"
#include "foedus/storage/storage_id.hpp"
#include "foedus/storage/masstree/fwd.hpp"
#include "foedus/storage/masstree/masstree_id.hpp"

namespace foedus {
namespace storage {
namespace masstree {
struct MasstreeMetadata CXX11_FINAL : public Metadata {
  enum Constants {
    kDefaultDropVolatilePagesBtreeLevels = 3,
  };
  MasstreeMetadata() :
    Metadata(0, kMasstreeStorage, ""),
    border_early_split_threshold_(0),
    snapshot_drop_volatile_pages_layer_threshold_(0),
    snapshot_drop_volatile_pages_btree_levels_(kDefaultDropVolatilePagesBtreeLevels),
    min_layer_hint_(0),
    pad1_(0) {}
  MasstreeMetadata(
    StorageId id,
    const StorageName& name,
    uint16_t border_early_split_threshold = 0,
    uint16_t snapshot_drop_volatile_pages_layer_threshold = 0,
    uint16_t snapshot_drop_volatile_pages_btree_levels = kDefaultDropVolatilePagesBtreeLevels,
    Layer min_layer_hint = 0)
    : Metadata(id, kMasstreeStorage, name),
      border_early_split_threshold_(border_early_split_threshold),
      snapshot_drop_volatile_pages_layer_threshold_(snapshot_drop_volatile_pages_layer_threshold),
      snapshot_drop_volatile_pages_btree_levels_(snapshot_drop_volatile_pages_btree_levels),
      min_layer_hint_(min_layer_hint),
      pad1_(0) {
  }
  MasstreeMetadata(
    const StorageName& name,
    uint16_t border_early_split_threshold = 0,
    uint16_t snapshot_drop_volatile_pages_layer_threshold = 0,
    uint16_t snapshot_drop_volatile_pages_btree_levels = kDefaultDropVolatilePagesBtreeLevels,
    Layer min_layer_hint = 0)
    : Metadata(0, kMasstreeStorage, name),
      border_early_split_threshold_(border_early_split_threshold),
      snapshot_drop_volatile_pages_layer_threshold_(snapshot_drop_volatile_pages_layer_threshold),
      snapshot_drop_volatile_pages_btree_levels_(snapshot_drop_volatile_pages_btree_levels),
      min_layer_hint_(min_layer_hint),
      pad1_(0) {
  }

  std::string describe() const;
  friend std::ostream& operator<<(std::ostream& o, const MasstreeMetadata& v);

  uint16_t border_early_split_threshold_;

  uint16_t snapshot_drop_volatile_pages_layer_threshold_;
  uint16_t snapshot_drop_volatile_pages_btree_levels_;

  Layer   min_layer_hint_;

  // just for valgrind when this metadata is written to file. ggr
  uint8_t pad1_;

  bool    should_aggresively_create_next_layer(Layer cur_layer, KeyLength remainder) const {
    if (remainder <= sizeof(KeySlice)) {
      return false;  // anyway can't create a next layer.
    }
    return min_layer_hint_ > cur_layer;
  }
};

struct MasstreeMetadataSerializer CXX11_FINAL : public virtual MetadataSerializer {
  MasstreeMetadataSerializer() : MetadataSerializer() {}
  explicit MasstreeMetadataSerializer(MasstreeMetadata* data)
    : MetadataSerializer(data), data_casted_(data) {}
  EXTERNALIZABLE(MasstreeMetadataSerializer);
  MasstreeMetadata* data_casted_;
};


}  // namespace masstree
}  // namespace storage
}  // namespace foedus
#endif  // FOEDUS_STORAGE_MASSTREE_MASSTREE_METADATA_HPP_