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/**
* Copyright (C) 2018-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 <functional>
#include "mongo/base/status.h"
#include "mongo/base/status_with.h"
#include "mongo/bson/bsonobj.h"
#include "mongo/db/record_id.h"
#include "mongo/db/repl/oplog_entry.h"
#include "mongo/db/repl/oplog_interface.h"
#include "mongo/db/repl/optime.h"
#include "mongo/util/fail_point.h"
namespace mongo {
namespace repl {
// It is necessary to have this forward declare for the mongo fail point
// at this location because of the splitting of the rollback algorithms into
// two separate files, rs_rollback and rs_rollback_no_uuid. However, after
// MongoDB 3.8 is released, we no longer need to maintain rs_rollback_no_uuid
// code and these forward declares can be removed. See SERVER-29766.
extern FailPoint rollbackHangBeforeFinish;
extern FailPoint rollbackHangThenFailAfterWritingMinValid;
// This is needed by rs_rollback and rollback_impl.
extern FailPoint rollbackHangAfterTransitionToRollback;
class RollBackLocalOperations {
RollBackLocalOperations(const RollBackLocalOperations&) = delete;
RollBackLocalOperations& operator=(const RollBackLocalOperations&) = delete;
public:
class RollbackCommonPoint {
public:
RollbackCommonPoint(BSONObj oplogBSON, RecordId recordId, BSONObj nextOplogBSON);
RecordId getRecordId() const {
return _recordId;
}
OpTime getOpTime() const {
return _opTime;
}
Date_t getWallClockTime() const {
return _wallClockTime;
}
Date_t getFirstOpWallClockTimeAfterCommonPoint() {
return _firstWallClockTimeAfterCommonPoint;
}
private:
RecordId _recordId;
OpTime _opTime;
Date_t _wallClockTime;
// The wall clock time of the first operation after the common point if it exists.
Date_t _firstWallClockTimeAfterCommonPoint;
};
/**
* Type of function to roll back an operation or process it for future use.
* It can return any status except ErrorCodes::NoSuchKey. See onRemoteOperation().
*/
using RollbackOperationFn = std::function<Status(const BSONObj&)>;
/**
* Initializes rollback processor with a valid local oplog.
* Whenever we encounter an operation in the local oplog that has to be rolled back,
* we will pass it to 'rollbackOperation'.
*/
RollBackLocalOperations(const OplogInterface& localOplog,
const RollbackOperationFn& rollbackOperation);
virtual ~RollBackLocalOperations() = default;
/**
* Process single remote operation.
* Returns ErrorCodes::NoSuchKey if common point has not been found and
* additional operations have to be read from the remote oplog.
*/
StatusWith<RollbackCommonPoint> onRemoteOperation(const BSONObj& operation);
private:
std::unique_ptr<OplogInterface::Iterator> _localOplogIterator;
RollbackOperationFn _rollbackOperation;
OplogInterface::Iterator::Value _localOplogValue;
unsigned long long _scanned;
};
/**
* Rolls back every operation in the local oplog that is not in the remote oplog, in reverse
* order.
*
* Whenever we encounter an operation in the local oplog that has to be rolled back,
* we will pass it to 'rollbackOperation' starting with the most recent operation.
* It is up to 'rollbackOperation' to roll back this operation immediately or
* process it for future use.
*/
StatusWith<RollBackLocalOperations::RollbackCommonPoint> syncRollBackLocalOperations(
const OplogInterface& localOplog,
const OplogInterface& remoteOplog,
const RollBackLocalOperations::RollbackOperationFn& rollbackOperation);
} // namespace repl
} // namespace mongo
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