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/**
* Copyright (C) 2022-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 <vector>
#include "mongo/bson/timestamp.h"
#include "mongo/db/operation_context.h"
#include "mongo/db/service_context.h"
#include "mongo/platform/mutex.h"
namespace mongo {
namespace topology_time_ticker_utils {
bool inRecoveryMode(OperationContext* opCtx);
}
/**
* This object is responsible for ticking the topology time of the Vector Clock when needed. It only
* exists on the CSRS nodes and it is associated with the mongod instance.
*
* Every time there is a local change on the topology of a sharded cluster this class registers a
* new TopologyTimeTickPoint. Once the oplog entry associated to that change is majority committed,
* we can advance the topology time.
* Since the tick points represent non-majority committed changes, this class has to handle what
* happens on rollback.
*/
class TopologyTimeTicker {
public:
TopologyTimeTicker() = default;
static TopologyTimeTicker& get(ServiceContext* serviceContext);
static TopologyTimeTicker& get(OperationContext* opCtx);
/**
* Registers a new tick point on _topologyTimeByLocalCommitTime.
* This method is invoked from two places:
* - From the OpObservers when writes modify config.shards
* - As part of the initialization of the VectorClock on the CSRS.
*/
void onNewLocallyCommittedTopologyTimeAvailable(Timestamp commitTime, Timestamp topologyTime);
/**
* Advances the topology time if one or more tick points have been majority committed.
*/
void onMajorityCommitPointUpdate(ServiceContext* service, const repl::OpTime& newCommitPoint);
/**
* Removes from _topologyTimeByLocalCommitTime any topology change that was rollbacked.
*/
void onReplicationRollback(const repl::OpTime& lastAppliedOpTime);
private:
Mutex _mutex = MONGO_MAKE_LATCH("TopologyTimeTicker");
/**
* Container that stores time-related information about a topology change in a sharded cluster.
* More specifically, the vector clock should start gossiping a new topologyTime once the
* related local commitTime is majority committed.
*/
std::map<Timestamp, Timestamp> _topologyTimeByLocalCommitTime;
};
} // namespace mongo
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