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101 lines
3.2 KiB
C++
101 lines
3.2 KiB
C++
#pragma once
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#include <string>
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#include <Processors/IProcessor.h>
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#include <Processors/RowsBeforeLimitCounter.h>
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#include <IO/Progress.h>
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namespace DB
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{
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class WriteBuffer;
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/** Output format have three inputs and no outputs. It writes data from WriteBuffer.
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*
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* First input is for main resultset, second is for "totals" and third is for "extremes".
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* It's not necessarily to connect "totals" or "extremes" ports (they may remain dangling).
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*
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* Data from input ports are pulled in order: first, from main input, then totals, then extremes.
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*
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* By default, data for "totals" and "extremes" is ignored.
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*/
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class IOutputFormat : public IProcessor
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{
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public:
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enum PortKind { Main = 0, Totals = 1, Extremes = 2 };
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protected:
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WriteBuffer & out;
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Chunk current_chunk;
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PortKind current_block_kind = PortKind::Main;
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bool has_input = false;
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bool finished = false;
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bool finalized = false;
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/// Flush data on each consumed chunk. This is intended for interactive applications to output data as soon as it's ready.
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bool auto_flush = false;
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RowsBeforeLimitCounterPtr rows_before_limit_counter;
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friend class ParallelFormattingOutputFormat;
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virtual void consume(Chunk) = 0;
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virtual void consumeTotals(Chunk) {}
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virtual void consumeExtremes(Chunk) {}
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virtual void finalize() {}
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public:
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IOutputFormat(const Block & header_, WriteBuffer & out_);
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Status prepare() override;
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void work() override;
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/// Flush output buffers if any.
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virtual void flush();
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void setAutoFlush() { auto_flush = true; }
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/// Value for rows_before_limit_at_least field.
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virtual void setRowsBeforeLimit(size_t /*rows_before_limit*/) {}
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/// Counter to calculate rows_before_limit_at_least in processors pipeline.
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void setRowsBeforeLimitCounter(RowsBeforeLimitCounterPtr counter) { rows_before_limit_counter.swap(counter); }
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/// Notify about progress. Method could be called from different threads.
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/// Passed value are delta, that must be summarized.
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virtual void onProgress(const Progress & /*progress*/) {}
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/// Set callback, which will be called before call to finalize().
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void setBeforeFinalizeCallback(std::function<void()> callback) { before_finalize_callback = callback; }
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/// Content-Type to set when sending HTTP response.
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virtual std::string getContentType() const { return "text/plain; charset=UTF-8"; }
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InputPort & getPort(PortKind kind) { return *std::next(inputs.begin(), kind); }
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/// Compatible to IBlockOutputStream interface
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void write(const Block & block);
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virtual void doWritePrefix() {}
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virtual void doWriteSuffix() { finalize(); }
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void setTotals(const Block & totals) { consumeTotals(Chunk(totals.getColumns(), totals.rows())); }
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void setExtremes(const Block & extremes) { consumeExtremes(Chunk(extremes.getColumns(), extremes.rows())); }
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size_t getResultRows() const { return result_rows; }
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size_t getResultBytes() const { return result_bytes; }
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private:
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/// Counters for consumed chunks. Are used for QueryLog.
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size_t result_rows = 0;
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size_t result_bytes = 0;
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bool prefix_written = false;
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std::function<void()> before_finalize_callback;
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};
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}
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