ClickHouse/src/Storages/MergeTree/ReplicatedMergeTreePartCheckThread.h
2023-05-16 15:26:24 +02:00

101 lines
3.5 KiB
C++

#pragma once
#include <set>
#include <map>
#include <list>
#include <mutex>
#include <thread>
#include <atomic>
#include <boost/noncopyable.hpp>
#include <Poco/Event.h>
#include <base/types.h>
#include <Core/BackgroundSchedulePool.h>
#include <Storages/CheckResults.h>
#include <Storages/MergeTree/IMergeTreeDataPart.h>
namespace DB
{
class StorageReplicatedMergeTree;
/** Checks the integrity of the parts requested for validation.
*
* Identifies the extra parts and removes them from the working set.
* Find the missing parts and add them for download from replicas.
* Checks the integrity of the data and, in the event of a violation,
* removes a part from the working set and adds it for download from replicas.
*/
class ReplicatedMergeTreePartCheckThread
{
public:
explicit ReplicatedMergeTreePartCheckThread(StorageReplicatedMergeTree & storage_);
~ReplicatedMergeTreePartCheckThread();
/// Processing of the queue to be checked is done in the background thread, which you must first start.
void start();
void stop();
/// Add a part (for which there are suspicions that it is missing, damaged or not needed) in the queue for check.
/// delay_to_check_seconds - check no sooner than the specified number of seconds.
void enqueuePart(const String & name, time_t delay_to_check_seconds = 0);
/// Get the number of parts in the queue for check.
size_t size() const;
/// Check part by name
CheckResult checkPart(const String & part_name);
std::unique_lock<std::mutex> pausePartsCheck();
/// Can be called only while holding a lock returned from pausePartsCheck()
void cancelRemovedPartsCheck(const MergeTreePartInfo & drop_range_info);
private:
void run();
/// Search for missing part and queue fetch if possible. Otherwise
/// remove part from zookeeper and queue.
void searchForMissingPartAndFetchIfPossible(const String & part_name, bool exists_in_zookeeper);
std::pair<bool, MergeTreeDataPartPtr> findLocalPart(const String & part_name);
enum MissingPartSearchResult
{
/// We found this part on other replica, let's fetch it.
FoundAndNeedFetch,
/// We found covering part or source part with same min and max block number
/// don't need to fetch because we should do it during normal queue processing.
FoundAndDontNeedFetch,
/// Covering part not found anywhere and exact part_name doesn't found on other
/// replicas.
LostForever,
};
/// Search for missing part on other replicas or covering part on all replicas (including our replica).
MissingPartSearchResult searchForMissingPartOnOtherReplicas(const String & part_name);
StorageReplicatedMergeTree & storage;
String log_name;
Poco::Logger * log;
using StringSet = std::set<String>;
using PartToCheck = std::pair<String, time_t>; /// The name of the part and the minimum time to check (or zero, if not important).
using PartsToCheckQueue = std::list<PartToCheck>;
/** Parts for which you want to check one of two:
* - If we have the part, check, its data with its checksums, and them with ZooKeeper.
* - If we do not have a part, check to see if it (or the part covering it) exists anywhere on another replicas.
*/
mutable std::mutex parts_mutex;
StringSet parts_set;
PartsToCheckQueue parts_queue;
std::mutex start_stop_mutex;
std::atomic<bool> need_stop { false };
BackgroundSchedulePool::TaskHolder task;
};
}