lbug 0.16.1

An in-process property graph database management system built for query speed and scalability
Documentation 
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#pragma once

#include <functional>

#include "common/copy_constructors.h"
#include "common/system_config.h"
#include "common/types/types.h"
#include "common/vector/value_vector.h"
#include "processor/result/factorized_table.h"
#include "processor/result/factorized_table_schema.h"

namespace lbug {
namespace storage {
class MemoryManager;
}
namespace processor {

using compare_function_t =
    std::function<bool(const common::ValueVector*, uint32_t, const uint8_t*)>;
using ft_compare_function_t =
    std::function<bool(const uint8_t*, const uint8_t*, const common::LogicalType& type)>;

class BaseHashTable {
public:
    BaseHashTable(storage::MemoryManager& memoryManager, common::logical_type_vec_t keyTypes);

    virtual ~BaseHashTable() = default;

    DELETE_COPY_DEFAULT_MOVE(BaseHashTable);

    const FactorizedTableSchema* getTableSchema() const {
        return factorizedTable->getTableSchema();
    }
    uint64_t getNumEntries() const { return factorizedTable->getNumTuples(); }
    uint64_t getCapacity() const { return maxNumHashSlots; }
    const FactorizedTable* getFactorizedTable() const { return factorizedTable.get(); }

protected:
    static constexpr uint64_t HASH_BLOCK_SIZE = common::TEMP_PAGE_SIZE;

    uint64_t getSlotIdxForHash(common::hash_t hash) const { return hash % maxNumHashSlots; }
    void setMaxNumHashSlots(uint64_t newSize);

    void computeVectorHashes(const std::vector<common::ValueVector*>& flatKeyVectors) {
        computeVectorHashes(constSpan(flatKeyVectors));
    }
    void computeVectorHashes(std::span<const common::ValueVector*> flatKeyVectors);
    void initSlotConstant(uint64_t numSlotsPerBlock);
    bool matchFlatVecWithEntry(const std::vector<common::ValueVector*>& keyVectors,
        const uint8_t* entry);

    template<typename T>
    std::span<const T*> constSpan(const std::vector<T*>& vector) {
        return std::span(const_cast<const T**>(vector.data()), vector.size());
    }

private:
    void initCompareFuncs();
    void initTmpHashVector();

protected:
    uint64_t maxNumHashSlots;
    uint64_t numSlotsPerBlockLog2;
    uint64_t slotIdxInBlockMask;
    std::vector<std::unique_ptr<DataBlock>> hashSlotsBlocks;
    storage::MemoryManager* memoryManager;
    std::unique_ptr<FactorizedTable> factorizedTable;
    std::vector<compare_function_t> compareEntryFuncs;
    std::vector<ft_compare_function_t> ftCompareEntryFuncs;
    std::vector<common::LogicalType> keyTypes;
    // Temporary arrays to hold intermediate results for appending.
    std::shared_ptr<common::DataChunkState> hashState;
    std::unique_ptr<common::ValueVector> hashVector;
    common::SelectionVector hashSelVec;
    std::unique_ptr<common::ValueVector> tmpHashResultVector;
    std::unique_ptr<common::ValueVector> tmpHashCombineResultVector;
};

} // namespace processor
} // namespace lbug