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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/Epoch.h"
#include "util/types.h"
namespace de {
template <ShardInterface ShardType, QueryInterface<ShardType> QueryType>
class BSMPolicy : ReconstructionPolicy<ShardType, QueryType> {
typedef std::vector<std::shared_ptr<InternalLevel<ShardType, QueryType>>>
LevelVector;
public:
BSMPolicy(size_t scale_factor, size_t buffer_size)
: m_scale_factor(scale_factor), m_buffer_size(buffer_size) {}
ReconstructionVector
get_reconstruction_tasks(Epoch<ShardType, QueryType> *epoch,
size_t incoming_reccnt) override {
ReconstructionVector reconstructions;
auto levels = epoch->get_structure()->get_level_vector();
level_index target_level = find_reconstruction_target(levels);
assert(target_level != -1);
level_index source_level = 0;
if (target_level == invalid_level_idx) {
/* grow */
target_level = levels.size();
}
ReconstructionTask task;
task.target = target_level;
task.type = ReconstructionType::Merge;
for (level_index i = target_level; i > source_level; i--) {
if (i < levels.size()) {
task.add_shard({i, all_shards_idx}, levels[i]->get_record_count());
}
}
reconstructions.add_reconstruction(task);
return reconstructions;
}
ReconstructionTask
get_flush_task(Epoch<ShardType, QueryType> *epoch) override {
return ReconstructionTask{
{{buffer_shid}}, 0, m_buffer_size, ReconstructionType::Flush};
}
private:
level_index find_reconstruction_target(LevelVector &levels) {
level_index target_level = 0;
for (size_t i = 0; i < (level_index)levels.size(); i++) {
if (levels[i].get_record_count() + 1 <= capacity(i)) {
target_level = i;
break;
}
}
return target_level;
}
inline size_t capacity(level_index level) {
return m_buffer_size * pow(m_scale_factor, level + 1);
}
size_t m_scale_factor;
size_t m_buffer_size;
};
} // namespace de
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