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38 lines
855 B
C++
38 lines
855 B
C++
#pragma once
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#include <DB/Columns/ColumnConst.h>
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#include <DB/DataStreams/IBlockOutputStream.h>
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#include <statdaemons/ext/range.hpp>
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namespace DB
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{
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/** Преобразует столбцы-константы в полноценные столбцы ("материализует" их).
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*/
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class MaterializingBlockOutputStream : public IBlockOutputStream
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{
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public:
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MaterializingBlockOutputStream(const BlockOutputStreamPtr & output) : output{output}
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{}
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void write(const Block & original_block) override
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{
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/// copy block to get rid of const
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auto block = original_block;
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for (const auto i : ext::range(0, block.columns()))
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{
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ColumnPtr & col = block.getByPosition(i).column;
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if (col->isConst())
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col = dynamic_cast<IColumnConst &>(*col).convertToFullColumn();
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}
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output->write(block);
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}
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BlockOutputStreamPtr output;
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};
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}
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