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#pragma once
#include <Processors/Merges/Algorithms/IMergingAlgorithm.h>
#include <Processors/Merges/Algorithms/RowRef.h>
#include <Core/SortDescription.h>
namespace DB
{
class IMergingAlgorithmWithDelayedChunk : public IMergingAlgorithm
{
public:
IMergingAlgorithmWithDelayedChunk(Block header_, size_t num_inputs, SortDescription description_);
protected:
SortingQueue<SortCursor> queue;
SortDescription description;
/// Previous row. May refer to last_chunk_sort_columns or row from source_chunks.
detail::RowRef last_key;
ColumnRawPtrs last_chunk_sort_columns; /// Point to last_chunk if valid.
void initializeQueue(Inputs inputs);
void updateCursor(Input & input, size_t source_num);
bool skipLastRowFor(size_t input_number) const { return current_inputs[input_number].skip_last_row; }
private:
Block header;
/// Inputs currently being merged.
Inputs current_inputs;
SortCursorImpls cursors;
/// In merging algorithm, we need to compare current sort key with the last one.
/// So, sorting columns for last row needed to be stored.
/// In order to do it, we extend lifetime of last chunk and it's sort columns (from corresponding sort cursor).
Chunk last_chunk;
};
}
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