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29 lines
774 B
C++
29 lines
774 B
C++
#pragma once
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#include <Processors/QueryPlan/IQueryPlanStep.h>
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namespace DB
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{
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/// Unite several logical streams of data into single logical stream with specified structure.
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class UnionStep : public IQueryPlanStep
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{
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public:
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/// max_threads is used to limit the number of threads for result pipeline.
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explicit UnionStep(DataStreams input_streams_, size_t max_threads_ = 0);
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String getName() const override { return "Union"; }
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QueryPipelineBuilderPtr updatePipeline(QueryPipelineBuilders pipelines, const BuildQueryPipelineSettings &) override;
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void describePipeline(FormatSettings & settings) const override;
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size_t getMaxThreads() const { return max_threads; }
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private:
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Block header;
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size_t max_threads;
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Processors processors;
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};
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}
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