mirror of
https://github.com/ClickHouse/ClickHouse.git
synced 2024-11-30 19:42:00 +00:00
106 lines
2.9 KiB
C++
106 lines
2.9 KiB
C++
#pragma once
|
|
|
|
#include <DB/Core/Exception.h>
|
|
#include <DB/Core/ErrorCodes.h>
|
|
#include <Yandex/MultiVersion.h>
|
|
#include <Yandex/logger_useful.h>
|
|
#include <Poco/Event.h>
|
|
#include <time.h>
|
|
#include <mutex>
|
|
#include <thread>
|
|
#include <unordered_map>
|
|
#include <chrono>
|
|
#include <random>
|
|
#include <unistd.h>
|
|
|
|
namespace DB
|
|
{
|
|
|
|
class Context;
|
|
class IDictionary;
|
|
|
|
/** Manages user-defined dictionaries.
|
|
* Monitors configuration file and automatically reloads dictionaries in a separate thread.
|
|
* The monitoring thread wakes up every @check_period_sec seconds and checks
|
|
* modification time of dictionaries' configuration file. If said time is greater than
|
|
* @config_last_modified, the dictionaries are created from scratch using configuration file,
|
|
* possibly overriding currently existing dictionaries with the same name (previous versions of
|
|
* overridden dictionaries will live as long as there are any users retaining them).
|
|
*
|
|
* Apart from checking configuration file for modifications, each non-cached dictionary
|
|
* has a lifetime of its own and may be updated if it's source reports that it has been
|
|
* modified. The time of next update is calculated by choosing uniformly a random number
|
|
* distributed between lifetime.min_sec and lifetime.max_sec.
|
|
* If either of lifetime.min_sec and lifetime.max_sec is zero, such dictionary is never updated.
|
|
*/
|
|
class ExternalDictionaries
|
|
{
|
|
private:
|
|
static const auto check_period_sec = 5;
|
|
|
|
friend class StorageSystemDictionaries;
|
|
|
|
mutable std::mutex dictionaries_mutex;
|
|
|
|
using dictionary_ptr_t = std::shared_ptr<MultiVersion<IDictionary>>;
|
|
struct dictionary_info final
|
|
{
|
|
dictionary_ptr_t dict;
|
|
std::string origin;
|
|
std::exception_ptr exception;
|
|
};
|
|
|
|
std::unordered_map<std::string, dictionary_info> dictionaries;
|
|
std::unordered_map<std::string, std::chrono::system_clock::time_point> update_times;
|
|
std::mt19937_64 rnd_engine{getSeed()};
|
|
|
|
Context & context;
|
|
|
|
std::thread reloading_thread;
|
|
Poco::Event destroy;
|
|
|
|
Logger * log;
|
|
|
|
std::unordered_map<std::string, Poco::Timestamp> last_modification_times;
|
|
|
|
void reloadImpl(bool throw_on_error = false);
|
|
void reloadFromFile(const std::string & config_path, bool throw_on_error);
|
|
|
|
void reloadPeriodically()
|
|
{
|
|
while (true)
|
|
{
|
|
if (destroy.tryWait(check_period_sec * 1000))
|
|
return;
|
|
|
|
reloadImpl();
|
|
}
|
|
}
|
|
|
|
static std::uint64_t getSeed()
|
|
{
|
|
timespec ts;
|
|
clock_gettime(CLOCK_MONOTONIC, &ts);
|
|
return ts.tv_nsec ^ getpid();
|
|
}
|
|
|
|
public:
|
|
/// Справочники будут обновляться в отдельном потоке, каждые reload_period секунд.
|
|
ExternalDictionaries(Context & context, const bool throw_on_error)
|
|
: context(context), log(&Logger::get("ExternalDictionaries"))
|
|
{
|
|
reloadImpl(throw_on_error);
|
|
reloading_thread = std::thread{&ExternalDictionaries::reloadPeriodically, this};
|
|
}
|
|
|
|
~ExternalDictionaries()
|
|
{
|
|
destroy.set();
|
|
reloading_thread.join();
|
|
}
|
|
|
|
MultiVersion<IDictionary>::Version getDictionary(const std::string & name) const;
|
|
};
|
|
|
|
}
|