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#include <Processors/QueryPlan/OffsetStep.h>
#include <Processors/OffsetTransform.h>
#include <QueryPipeline/QueryPipelineBuilder.h>
#include <IO/Operators.h>
#include <Common/JSONBuilder.h>
namespace DB
{
static ITransformingStep::Traits getTraits()
{
return ITransformingStep::Traits
{
{
.returns_single_stream = false,
.preserves_number_of_streams = true,
.preserves_sorting = true,
},
{
.preserves_number_of_rows = false,
}
};
}
OffsetStep::OffsetStep(const DataStream & input_stream_, size_t offset_)
: ITransformingStep(input_stream_, input_stream_.header, getTraits())
, offset(offset_)
{
}
void OffsetStep::transformPipeline(QueryPipelineBuilder & pipeline, const BuildQueryPipelineSettings &)
{
auto transform = std::make_shared<OffsetTransform>(
pipeline.getHeader(), offset, pipeline.getNumStreams());
pipeline.addTransform(std::move(transform));
}
void OffsetStep::describeActions(FormatSettings & settings) const
{
settings.out << String(settings.offset, ' ') << "Offset " << offset << '\n';
}
void OffsetStep::describeActions(JSONBuilder::JSONMap & map) const
{
map.add("Offset", offset);
}
}
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