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112 lines
2.9 KiB
C++
112 lines
2.9 KiB
C++
#ifndef DBMS_STORAGES_STORAGE_LOG_H
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#define DBMS_STORAGES_STORAGE_LOG_H
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#include <map>
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#include <Poco/SharedPtr.h>
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#include <Poco/File.h>
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#include <Poco/FileStream.h>
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#include <DB/Core/NamesAndTypes.h>
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#include <DB/IO/ReadBufferFromIStream.h>
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#include <DB/IO/WriteBufferFromOStream.h>
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#include <DB/IO/CompressedReadBuffer.h>
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#include <DB/IO/CompressedWriteBuffer.h>
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#include <DB/Storages/IStorage.h>
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namespace DB
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{
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using Poco::SharedPtr;
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class StorageLog;
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class LogBlockInputStream : public IBlockInputStream
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{
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public:
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LogBlockInputStream(size_t block_size_, const Names & column_names_, StorageLog & storage_);
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Block read();
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private:
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size_t block_size;
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const Names & column_names;
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StorageLog & storage;
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struct Stream
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{
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Stream(const std::string & path)
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: istr(path, std::ios::in | std::ios::binary), plain(istr), compressed(plain) {}
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Poco::FileInputStream istr;
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ReadBufferFromIStream plain;
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CompressedReadBuffer compressed;
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};
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typedef std::map<std::string, SharedPtr<Stream> > FileStreams;
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FileStreams streams;
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};
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class LogBlockOutputStream : public IBlockOutputStream
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{
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public:
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LogBlockOutputStream(StorageLog & storage_);
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void write(const Block & block);
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private:
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StorageLog & storage;
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struct Stream
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{
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Stream(const std::string & path)
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: ostr(path, std::ios::out | std::ios::ate | std::ios::binary), plain(ostr), compressed(plain) {}
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Poco::FileOutputStream ostr;
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WriteBufferFromOStream plain;
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CompressedWriteBuffer compressed;
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};
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typedef std::map<std::string, SharedPtr<Stream> > FileStreams;
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FileStreams streams;
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};
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/** Реализует хранилище, подходящее для логов.
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* В нём не поддерживаются ключи; запись блокирует всю таблицу.
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* Данные хранятся в сжатом виде.
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*/
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class StorageLog : public IStorage
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{
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friend class LogBlockInputStream;
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friend class LogBlockOutputStream;
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public:
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/** Подцепить таблицу с соответствующим именем, по соответствующему пути (с / на конце),
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* (корректность имён и путей не проверяется)
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* состоящую из указанных столбцов; создать файлы, если их нет.
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*/
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StorageLog(const std::string & path_, const std::string & name_, SharedPtr<NamesAndTypes> columns_,
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const std::string & extension_ = ".bin");
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std::string getName() const { return "Log"; }
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SharedPtr<IBlockInputStream> read(
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const Names & column_names,
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const ptree & query,
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size_t max_block_size = DEFAULT_BLOCK_SIZE);
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SharedPtr<IBlockOutputStream> write(
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const ptree & query);
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private:
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const std::string path;
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const std::string name;
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SharedPtr<NamesAndTypes> columns;
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const std::string extension;
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typedef std::map<std::string, Poco::File> Files_t;
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Files_t files;
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};
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}
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#endif
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