ClickHouse/src/Storages/StorageSet.h
2020-06-18 19:10:47 +03:00

89 lines
2.4 KiB
C++

#pragma once
#include <ext/shared_ptr_helper.h>
#include <Storages/IStorage.h>
namespace DB
{
class Set;
using SetPtr = std::shared_ptr<Set>;
/** Common part of StorageSet and StorageJoin.
*/
class StorageSetOrJoinBase : public IStorage
{
friend class SetOrJoinBlockOutputStream;
public:
void rename(const String & new_path_to_table_data, const StorageID & new_table_id) override;
BlockOutputStreamPtr write(const ASTPtr & query, const StorageMetadataPtr & /*metadata_snapshot*/, const Context & context) override;
Strings getDataPaths() const override { return {path}; }
protected:
StorageSetOrJoinBase(
const String & relative_path_,
const StorageID & table_id_,
const ColumnsDescription & columns_,
const ConstraintsDescription & constraints_,
const Context & context_);
String base_path;
String path;
std::atomic<UInt64> increment = 0; /// For the backup file names.
/// Restore from backup.
void restore();
private:
void restoreFromFile(const String & file_path);
/// Insert the block into the state.
virtual void insertBlock(const Block & block) = 0;
/// Call after all blocks were inserted.
virtual void finishInsert() = 0;
virtual size_t getSize() const = 0;
};
/** Lets you save the set for later use on the right side of the IN statement.
* When inserted into a table, the data will be inserted into the set,
* and also written to a file-backup, for recovery after a restart.
* Reading from the table is not possible directly - it is possible to specify only the right part of the IN statement.
*/
class StorageSet final : public ext::shared_ptr_helper<StorageSet>, public StorageSetOrJoinBase
{
friend struct ext::shared_ptr_helper<StorageSet>;
public:
String getName() const override { return "Set"; }
/// Access the insides.
SetPtr & getSet() { return set; }
void truncate(const ASTPtr &, const StorageMetadataPtr & metadata_snapshot, const Context &, TableExclusiveLockHolder &) override;
private:
SetPtr set;
void insertBlock(const Block & block) override;
void finishInsert() override;
size_t getSize() const override;
protected:
StorageSet(
const String & relative_path_,
const StorageID & table_id_,
const ColumnsDescription & columns_,
const ConstraintsDescription & constraints_,
const Context & context_);
};
}