mirror of
https://github.com/ClickHouse/ClickHouse.git
synced 2024-11-30 19:42:00 +00:00
148 lines
4.3 KiB
C++
148 lines
4.3 KiB
C++
#pragma once
|
||
|
||
#include <DB/Dictionaries/IDictionary.h>
|
||
#include <DB/Common/Exception.h>
|
||
#include <DB/Common/setThreadName.h>
|
||
#include <common/MultiVersion.h>
|
||
#include <common/logger_useful.h>
|
||
#include <Poco/Event.h>
|
||
#include <unistd.h>
|
||
#include <time.h>
|
||
#include <mutex>
|
||
#include <thread>
|
||
#include <unordered_map>
|
||
#include <chrono>
|
||
#include <random>
|
||
|
||
namespace DB
|
||
{
|
||
|
||
class Context;
|
||
|
||
/** 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<IDictionaryBase>>;
|
||
struct dictionary_info final
|
||
{
|
||
dictionary_ptr_t dict;
|
||
std::string origin;
|
||
std::exception_ptr exception;
|
||
};
|
||
|
||
struct failed_dictionary_info final
|
||
{
|
||
std::unique_ptr<IDictionaryBase> dict;
|
||
std::chrono::system_clock::time_point next_attempt_time;
|
||
std::uint64_t error_count;
|
||
};
|
||
|
||
/** Имя словаря -> словарь.
|
||
*/
|
||
std::unordered_map<std::string, dictionary_info> dictionaries;
|
||
|
||
/** Здесь находятся словари, которых ещё ни разу не удалось загрузить.
|
||
* В dictionaries они тоже присутствуют, но с нулевым указателем dict.
|
||
*/
|
||
std::unordered_map<std::string, failed_dictionary_info> failed_dictionaries;
|
||
|
||
/** И для обычных и для failed_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()
|
||
{
|
||
setThreadName("ExterDictReload");
|
||
|
||
while (true)
|
||
{
|
||
if (destroy.tryWait(check_period_sec * 1000))
|
||
return;
|
||
|
||
reloadImpl();
|
||
}
|
||
}
|
||
|
||
static std::uint64_t getSeed()
|
||
{
|
||
timespec ts;
|
||
clock_gettime(CLOCK_MONOTONIC, &ts);
|
||
return static_cast<std::uint64_t>(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"))
|
||
{
|
||
{
|
||
/** При синхронной загрузки внешних словарей в момент выполнения запроса,
|
||
* не нужно использовать ограничение на расход памяти запросом.
|
||
*/
|
||
struct TemporarilyDisableMemoryTracker
|
||
{
|
||
MemoryTracker * memory_tracker;
|
||
|
||
TemporarilyDisableMemoryTracker()
|
||
{
|
||
memory_tracker = current_memory_tracker;
|
||
current_memory_tracker = nullptr;
|
||
}
|
||
|
||
~TemporarilyDisableMemoryTracker()
|
||
{
|
||
current_memory_tracker = memory_tracker;
|
||
}
|
||
} temporarily_disable_memory_tracker;
|
||
|
||
reloadImpl(throw_on_error);
|
||
}
|
||
|
||
reloading_thread = std::thread{&ExternalDictionaries::reloadPeriodically, this};
|
||
}
|
||
|
||
~ExternalDictionaries()
|
||
{
|
||
destroy.set();
|
||
reloading_thread.join();
|
||
}
|
||
|
||
MultiVersion<IDictionaryBase>::Version getDictionary(const std::string & name) const;
|
||
};
|
||
|
||
}
|