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/*
* include/framework/reconstruction/LevelingPolicy.h
*
* Copyright (C) 2023-2024 Douglas B. Rumbaugh <drumbaugh@psu.edu>
* Dong Xie <dongx@psu.edu>
*
* Distributed under the Modified BSD License.
*
*/
#pragma once
#include <cmath>
#include "framework/reconstruction/ReconstructionPolicy.h"
#include "framework/scheduling/Version.h"
#include "util/types.h"
namespace de {
template <ShardInterface ShardType, QueryInterface<ShardType> QueryType>
class TieringPolicy : public ReconstructionPolicy<ShardType, QueryType> {
typedef std::vector<std::shared_ptr<InternalLevel<ShardType, QueryType>>>
LevelVector;
public:
TieringPolicy(size_t scale_factor, size_t buffer_size, double modifier = 0)
: m_scale_factor(scale_factor), m_buffer_size(buffer_size),
m_size_modifier(modifier) {}
std::vector<ReconstructionVector>
get_reconstruction_tasks(const Version<ShardType, QueryType> *version,
LockManager &lock_mngr) const override {
return {};
}
ReconstructionVector
get_flush_tasks(const Version<ShardType, QueryType> *version) const override {
ReconstructionVector reconstructions;
auto levels = version->get_structure()->get_level_vector();
level_index target_level = find_reconstruction_target(
levels, version->get_structure()->get_record_count());
assert(target_level != -1);
level_index source_level = 0;
if (target_level == invalid_level_idx) {
/* grow */
target_level = levels.size();
}
for (level_index i = target_level; i > source_level; i--) {
size_t total_reccnt = levels[i - 1]->get_record_count();
std::vector<ShardID> shards;
for (ssize_t j = 0; j < (ssize_t)levels[i - 1]->get_shard_count(); j++) {
shards.push_back({i - 1, j});
}
if (total_reccnt > 0 || shards.size() > 0) {
reconstructions.add_reconstruction(shards, i, total_reccnt,
ReconstructionType::Compact);
}
}
return reconstructions;
}
private:
level_index find_reconstruction_target(LevelVector &levels,
size_t reccnt) const {
level_index target_level = invalid_level_idx;
for (level_index i = 1; i < (level_index)levels.size(); i++) {
if (levels[i]->get_shard_count() + 1 <= capacity(reccnt)) {
target_level = i;
break;
}
}
return target_level;
}
inline size_t capacity(size_t reccnt) const {
return std::ceil((double)m_scale_factor *
std::pow<double>(std::log10(reccnt), m_size_modifier));
}
size_t m_scale_factor;
size_t m_buffer_size;
double m_size_modifier;
};
} // namespace de
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