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100 lines
2.6 KiB
C++
100 lines
2.6 KiB
C++
#pragma once
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#include <iomanip>
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#include <Yandex/logger_useful.h>
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#include <DB/Columns/ColumnAggregateFunction.h>
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#include <DB/DataStreams/IProfilingBlockInputStream.h>
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#include <DB/Interpreters/Aggregator.h>
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namespace DB
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{
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using Poco::SharedPtr;
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/** Преобразует агрегатные функции (с промежуточным состоянием) в потоке блоков в конечные значения.
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*/
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class FinalizingAggregatedBlockInputStream : public IProfilingBlockInputStream
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{
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public:
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FinalizingAggregatedBlockInputStream(BlockInputStreamPtr input_, AggregateDescriptions & aggregates_)
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: aggregates(aggregates_), log(&Logger::get("FinalizingAggregatedBlockInputStream"))
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{
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children.push_back(input_);
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}
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String getName() const { return "FinalizingAggregatedBlockInputStream"; }
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String getID() const
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{
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std::stringstream res;
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res << "FinalizingAggregated(" << children.back()->getID() << ")";
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return res.str();
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}
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protected:
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Block readImpl()
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{
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Block res = children.back()->read();
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if (!res)
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return res;
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LOG_TRACE(log, "Finalizing aggregate functions");
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Stopwatch watch;
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finalizeBlock(res);
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double elapsed_seconds = watch.elapsedSeconds();
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if (elapsed_seconds > 0.001)
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{
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LOG_TRACE(log, std::fixed << std::setprecision(3)
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<< "Finalized aggregate functions. "
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<< res.rows() << " rows, " << res.bytes() / 1048576.0 << " MiB"
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<< " in " << elapsed_seconds << " sec."
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<< " (" << res.rows() / elapsed_seconds << " rows/sec., " << res.bytes() / elapsed_seconds / 1048576.0 << " MiB/sec.)");
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}
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return res;
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}
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private:
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AggregateDescriptions aggregates;
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Logger * log;
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void finalizeBlock(Block & res)
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{
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size_t rows = res.rows();
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size_t columns = res.columns();
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size_t number_of_aggregate = 0;
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for (size_t i = 0; i < columns; ++i)
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{
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ColumnWithNameAndType & column = res.getByPosition(i);
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if (ColumnAggregateFunction * col = dynamic_cast<ColumnAggregateFunction *>(&*column.column))
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{
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ColumnAggregateFunction::Container_t & data = col->getData();
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IAggregateFunction * func = aggregates[number_of_aggregate].function;
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column.type = func->getReturnType();
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ColumnPtr finalized_column_ptr = column.type->createColumn();
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IColumn & finalized_column = *finalized_column_ptr;
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finalized_column.reserve(rows);
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for (size_t j = 0; j < rows; ++j)
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func->insertResultInto(data[j], finalized_column);
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/// Заменяем в блоке столбец на финализированный.
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column.column = finalized_column_ptr;
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++number_of_aggregate;
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}
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}
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}
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};
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}
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