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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 "mongo/base/status.h"
#include "mongo/db/concurrency/lock_manager_defs.h"
#include "mongo/db/service_context.h"
#include <memory>
namespace mongo {
class TicketHolder;
class TicketHolders {
public:
static Status updateConcurrentWriteTransactions(const int& newWriteTransactions);
static Status updateConcurrentReadTransactions(const int& newReadTransactions);
static TicketHolders& get(ServiceContext* svcCtx);
static TicketHolders& get(ServiceContext& svcCtx);
/**
* Sets the TicketHolder implementation to use to obtain tickets from 'reading' (for MODE_S and
* MODE_IS), and from 'writing' (for MODE_IX) in order to throttle database access. There is no
* throttling for MODE_X, as there can only ever be a single locker using this mode. The
* throttling is intended to defend against large drops in throughput under high load due to too
* much concurrency.
*/
void setGlobalThrottling(std::unique_ptr<TicketHolder> reading,
std::unique_ptr<TicketHolder> writing);
TicketHolder* getTicketHolder(LockMode mode);
private:
std::unique_ptr<TicketHolder> _openWriteTransaction;
std::unique_ptr<TicketHolder> _openReadTransaction;
};
} // namespace mongo
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