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120 lines
3.5 KiB
C++
120 lines
3.5 KiB
C++
#pragma once
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#include <DB/DataStreams/IBlockOutputStream.h>
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#include <DB/Client/Connection.h>
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#include <common/logger_useful.h>
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#include <DB/Common/NetException.h>
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namespace DB
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{
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namespace ErrorCodes
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{
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extern const int UNEXPECTED_PACKET_FROM_SERVER;
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extern const int LOGICAL_ERROR;
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}
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/** Позволяет выполнить запрос INSERT на удалённом сервере и отправить данные.
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*/
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class RemoteBlockOutputStream : public IBlockOutputStream
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{
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public:
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RemoteBlockOutputStream(Connection & connection_, const String & query_, const Settings * settings_ = nullptr)
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: connection(connection_), query(query_), settings(settings_)
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{
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}
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/// Можно вызывать после writePrefix, чтобы получить структуру таблицы.
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Block getSampleBlock() const
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{
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return sample_block;
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}
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void writePrefix() override
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{
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/** Отправляет запрос и получает блок-пример, описывающий структуру таблицы.
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* Он нужен, чтобы знать, какие блоки передавать в метод write.
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*/
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connection.sendQuery(query, "", QueryProcessingStage::Complete, settings, nullptr);
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Connection::Packet packet = connection.receivePacket();
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if (Protocol::Server::Data == packet.type)
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{
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sample_block = packet.block;
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if (!sample_block)
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throw Exception("Logical error: empty block received as table structure", ErrorCodes::LOGICAL_ERROR);
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}
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else if (Protocol::Server::Exception == packet.type)
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{
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packet.exception->rethrow();
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return;
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}
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else
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throw NetException("Unexpected packet from server (expected Data or Exception, got "
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+ String(Protocol::Server::toString(packet.type)) + ")", ErrorCodes::UNEXPECTED_PACKET_FROM_SERVER);
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}
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void write(const Block & block) override
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{
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if (!sample_block)
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throw Exception("You must call IBlockOutputStream::writePrefix before IBlockOutputStream::write", ErrorCodes::LOGICAL_ERROR);
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if (!blocksHaveEqualStructure(block, sample_block))
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{
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std::stringstream message;
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message << "Block structure is different from table structure.\n"
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<< "\nTable structure:\n(" << sample_block.dumpStructure() << ")\nBlock structure:\n(" << block.dumpStructure() << ")\n";
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LOG_ERROR(&Logger::get("RemoteBlockOutputStream"), message.str());
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throw DB::Exception(message.str());
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}
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connection.sendData(block);
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}
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/// Отправить блок данных, который уже был заранее сериализован (и, если надо, сжат), который следует прочитать из input-а.
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void writePrepared(ReadBuffer & input, size_t size = 0)
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{
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/// Не можем использовать sample_block.
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connection.sendPreparedData(input, size);
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}
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void writeSuffix() override
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{
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/// Пустой блок означает конец данных.
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connection.sendData(Block());
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/// Получаем пакет EndOfStream.
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Connection::Packet packet = connection.receivePacket();
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if (Protocol::Server::EndOfStream == packet.type)
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{
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/// Ничего.
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}
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else if (Protocol::Server::Exception == packet.type)
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packet.exception->rethrow();
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else
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throw NetException("Unexpected packet from server (expected EndOfStream or Exception, got "
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+ String(Protocol::Server::toString(packet.type)) + ")", ErrorCodes::UNEXPECTED_PACKET_FROM_SERVER);
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}
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private:
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Connection & connection;
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String query;
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const Settings * settings;
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Block sample_block;
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};
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}
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