ClickHouse/dbms/include/DB/Storages/System/StorageSystemNumbers.h
2016-12-08 05:49:04 +03:00

47 lines
1.3 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 <ext/shared_ptr_helper.hpp>
#include <DB/Storages/IStorage.h>
namespace DB
{
class Context;
/** Реализует хранилище для системной таблицы Numbers.
* Таблица содержит единственный столбец number UInt64.
* Из этой таблицы можно прочитать все натуральные числа, начиная с 0 (до 2^64 - 1, а потом заново).
*/
class StorageSystemNumbers : private ext::shared_ptr_helper<StorageSystemNumbers>, public IStorage
{
friend class ext::shared_ptr_helper<StorageSystemNumbers>;
public:
static StoragePtr create(const std::string & name_, bool multithreaded_ = false);
std::string getName() const override { return "SystemNumbers"; }
std::string getTableName() const override { return name; }
const NamesAndTypesList & getColumnsListImpl() const override { return columns; }
BlockInputStreams read(
const Names & column_names,
ASTPtr query,
const Context & context,
const Settings & settings,
QueryProcessingStage::Enum & processed_stage,
size_t max_block_size = DEFAULT_BLOCK_SIZE,
unsigned threads = 1) override;
private:
const std::string name;
NamesAndTypesList columns;
bool multithreaded;
StorageSystemNumbers(const std::string & name_, bool multithreaded_);
};
}