ClickHouse/dbms/include/DB/DataStreams/RemoteBlockOutputStream.h
2015-09-29 22:19:54 +03:00

113 lines
3.4 KiB
C++
Raw Blame History

This file contains ambiguous Unicode characters

This file contains Unicode characters that might be confused with other characters. If you think that this is intentional, you can safely ignore this warning. Use the Escape button to reveal them.

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