ClickHouse/dbms/src/Interpreters/IExternalLoadable.h
Vitaly Baranov b4384ce2a9 Dictionaries can be loaded in parallel.
A bad dictionary cannot block all the loading anymore.
Implemented really lazy loading of external dictionaries.
Provided more detailed information about the loading of each dictionary
to make diagnostics easier.
2019-06-14 22:18:47 +03:00

51 lines
1.4 KiB
C++

#pragma once
#include <chrono>
#include <string>
#include <memory>
#include <boost/noncopyable.hpp>
#include <Core/Types.h>
namespace Poco::Util
{
class AbstractConfiguration;
}
namespace DB
{
/// Min and max lifetimes for a loadable object or it's entry
struct ExternalLoadableLifetime
{
UInt64 min_sec;
UInt64 max_sec;
ExternalLoadableLifetime(const Poco::Util::AbstractConfiguration & config, const std::string & config_prefix);
};
/// Basic interface for external loadable objects. Is used in ExternalLoader.
class IExternalLoadable : public std::enable_shared_from_this<IExternalLoadable>, private boost::noncopyable
{
public:
virtual ~IExternalLoadable() = default;
virtual const ExternalLoadableLifetime & getLifetime() const = 0;
virtual std::string getName() const = 0;
/// True if object can be updated when lifetime exceeded.
virtual bool supportUpdates() const = 0;
/// If lifetime exceeded and isModified(), ExternalLoader replace current object with the result of clone().
virtual bool isModified() const = 0;
/// Returns new object with the same configuration. Is used to update modified object when lifetime exceeded.
virtual std::shared_ptr<const IExternalLoadable> clone() const = 0;
virtual std::chrono::time_point<std::chrono::system_clock> getCreationTime() const = 0;
virtual std::exception_ptr getCreationException() const = 0;
};
}