ClickHouse/dbms/src/Storages/StorageMemory.h

72 lines
1.9 KiB
C++

#pragma once
#include <mutex>
#include <ext/shared_ptr_helper.h>
#include <Core/NamesAndTypes.h>
#include <Storages/IStorage.h>
#include <DataStreams/IBlockOutputStream.h>
namespace DB
{
class StorageMemory;
/** Implements storage in the RAM.
* Suitable for temporary data.
* It does not support keys.
* Data is stored as a set of blocks and is not stored anywhere else.
*/
class StorageMemory : public ext::shared_ptr_helper<StorageMemory>, public IStorage
{
friend class ext::shared_ptr_helper<StorageMemory>;
friend class MemoryBlockInputStream;
friend class MemoryBlockOutputStream;
public:
std::string getName() const override { return "Memory"; }
std::string getTableName() const override { return name; }
const NamesAndTypesList & getColumnsListImpl() const override { return *columns; }
size_t getSize() const { return data.size(); }
BlockInputStreams read(
const Names & column_names,
const SelectQueryInfo & query_info,
const Context & context,
QueryProcessingStage::Enum & processed_stage,
size_t max_block_size,
unsigned num_streams) override;
BlockOutputStreamPtr write(const ASTPtr & query, const Settings & settings) override;
void drop() override;
void rename(const String & new_path_to_db, const String & new_database_name, const String & new_table_name) override { name = new_table_name; }
private:
String name;
NamesAndTypesListPtr columns;
/// The data itself. `list` - so that when inserted to the end, the existing iterators are not invalidated.
BlocksList data;
std::mutex mutex;
StorageMemory(
const std::string & name_,
NamesAndTypesListPtr columns_);
StorageMemory(
const std::string & name_,
NamesAndTypesListPtr columns_,
const NamesAndTypesList & materialized_columns_,
const NamesAndTypesList & alias_columns_,
const ColumnDefaults & column_defaults_);
};
}