CardinalityEstimator.h File Reference

Estimators to be used when precise cardinality isn't useful. More...

#include "RelAlgExecutionUnit.h"
#include "../Analyzer/Analyzer.h"
#include "Logger/Logger.h"

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Classes
class	CardinalityEstimationRequired
class	Analyzer::Estimator
class	Analyzer::NDVEstimator
class	Analyzer::LargeNDVEstimator

Namespaces
	Analyzer

Functions
ResultSetPtr	reduce_estimator_results (const RelAlgExecutionUnit &ra_exe_unit, std::vector< std::pair< ResultSetPtr, std::vector< size_t >>> &results_per_device)

Detailed Description

Estimators to be used when precise cardinality isn't useful.

Definition in file CardinalityEstimator.h.

Function Documentation

ResultSetPtr reduce_estimator_results	(	const RelAlgExecutionUnit &	ra_exe_unit,
		std::vector< std::pair< ResultSetPtr, std::vector< size_t >>> &	results_per_device
	)

Definition at line 141 of file CardinalityEstimator.cpp.

References CHECK, and RelAlgExecutionUnit::estimator.

Referenced by Executor::reduceMultiDeviceResults().

                                                                             {
  if (results_per_device.empty()) {
    return nullptr;
  }
  CHECK(dynamic_cast<const Analyzer::NDVEstimator*>(ra_exe_unit.estimator.get()));
  const auto& result_set = results_per_device.front().first;
  CHECK(result_set);
  auto estimator_buffer = result_set->getHostEstimatorBuffer();
  CHECK(estimator_buffer);
  for (size_t i = 1; i < results_per_device.size(); ++i) {
    const auto& next_result_set = results_per_device[i].first;
    const auto other_estimator_buffer = next_result_set->getHostEstimatorBuffer();
    for (size_t off = 0; off < ra_exe_unit.estimator->getBufferSize(); ++off) {
      estimator_buffer[off] |= other_estimator_buffer[off];
    }
  }
  return std::move(result_set);
}

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