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/**
* Copyright (C) 2020-present MongoDB, Inc.
*
* This program is free software: you can redistribute it and/or modify
* it under the terms of the Server Side Public License, version 1,
* as published by MongoDB, Inc.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* Server Side Public License for more details.
*
* You should have received a copy of the Server Side Public License
* along with this program. If not, see
* <http://www.mongodb.com/licensing/server-side-public-license>.
*
* As a special exception, the copyright holders give permission to link the
* code of portions of this program with the OpenSSL library under certain
* conditions as described in each individual source file and distribute
* linked combinations including the program with the OpenSSL library. You
* must comply with the Server Side Public License in all respects for
* all of the code used other than as permitted herein. If you modify file(s)
* with this exception, you may extend this exception to your version of the
* file(s), but you are not obligated to do so. If you do not wish to do so,
* delete this exception statement from your version. If you delete this
* exception statement from all source files in the program, then also delete
* it in the license file.
*/
#pragma once
#include "mongo/util/concurrency/with_lock.h"
#include "mongo/util/periodic_runner.h"
namespace mongo {
class OperationContext;
class ServiceContext;
/**
* Owns a periodic background job that tracks the number of sharded collections that have
* inconsistent indexes across shards. The job only runs on the primary node in the config server
* replica set.
*/
class PeriodicShardedIndexConsistencyChecker final {
PeriodicShardedIndexConsistencyChecker(const PeriodicShardedIndexConsistencyChecker&) = delete;
PeriodicShardedIndexConsistencyChecker& operator=(
const PeriodicShardedIndexConsistencyChecker&) = delete;
public:
PeriodicShardedIndexConsistencyChecker() = default;
~PeriodicShardedIndexConsistencyChecker() = default;
PeriodicShardedIndexConsistencyChecker(PeriodicShardedIndexConsistencyChecker&& source) =
delete;
PeriodicShardedIndexConsistencyChecker& operator=(
PeriodicShardedIndexConsistencyChecker&& other) = delete;
/**
* Obtains the service-wide PeriodicShardedIndexConsistencyChecker instance.
*/
static PeriodicShardedIndexConsistencyChecker& get(OperationContext* opCtx);
static PeriodicShardedIndexConsistencyChecker& get(ServiceContext* serviceContext);
long long getNumShardedCollsWithInconsistentIndexes() const;
/**
* Invoked when the config server primary enters the 'PRIMARY' state to
* trigger the start of the periodic sharded index consistency check.
*/
void onStepUp(ServiceContext* serviceContext);
/**
* Invoked when this node which is currently serving as a 'PRIMARY' steps down.
*
* Pauses the periodic job until subsequent step up. This method might be called
* multiple times in succession, which is what happens as a result of incomplete
* transition to primary so it is resilient to that.
*/
void onStepDown();
/**
* Invoked when this node is shutting down. Stops the periodic job.
*/
void onShutDown();
private:
/**
* Initializes and starts the periodic job.
*/
void _launchShardedIndexConsistencyChecker(WithLock, ServiceContext* serviceContext);
// Protects the variables below. Uses acquisition level 1 because it will be held while starting
// a periodic job, which resolves a future.
mutable Mutex _mutex = MONGO_MAKE_LATCH(HierarchicalAcquisitionLevel(1),
"PeriodicShardedIndexConsistencyChecker::_mutex");
// Periodic job for counting inconsistent indexes in the cluster.
PeriodicJobAnchor _shardedIndexConsistencyChecker;
// The latest count of sharded collections with inconsistent indexes.
long long _numShardedCollsWithInconsistentIndexes{0};
bool _isPrimary{false};
};
} // namespace mongo
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