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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 <memory>
#include "mongo/db/logical_session_id.h"
#include "mongo/db/sessions_collection.h"
#include "mongo/util/time_support.h"
namespace mongo {
class OperationContext;
/**
* Accesses the sessions collection for mongos and shard servers.
*/
class SessionsCollectionSharded : public SessionsCollection {
public:
/**
* Ensures that the sessions collection exists, is sharded,
* and has the proper indexes.
*/
Status setupSessionsCollection(OperationContext* opCtx) override;
/**
* Checks if the sessions collection exists. Does not check if the index exists in the sharded
* version of this function.
*/
virtual Status checkSessionsCollectionExists(OperationContext* opCtx) override;
/**
* Updates the last-use times on the given sessions to be greater than
* or equal to the current time.
*/
Status refreshSessions(OperationContext* opCtx,
const LogicalSessionRecordSet& sessions) override;
/**
* Removes the authoritative records for the specified sessions.
*/
Status removeRecords(OperationContext* opCtx, const LogicalSessionIdSet& sessions) override;
StatusWith<LogicalSessionIdSet> findRemovedSessions(
OperationContext* opCtx, const LogicalSessionIdSet& sessions) override;
protected:
Status _checkCacheForSessionsCollection(OperationContext* opCtx);
/**
* These two methods use the sharding routing metadata to do a best effort attempt at grouping
* the specified set of sessions by the shards, which have the records for these sessions. This
* is done as an attempt to avoid broadcast queries.
*
* The reason it is 'best effort' is because it makes no attempt at checking whether the routing
* table is up-to-date and just picks up whatever was most recently fetched from the config
* server, which could be stale.
*/
std::vector<LogicalSessionId> _groupSessionIdsByOwningShard(
OperationContext* opCtx, const LogicalSessionIdSet& sessions);
std::vector<LogicalSessionRecord> _groupSessionRecordsByOwningShard(
OperationContext* opCtx, const LogicalSessionRecordSet& sessions);
};
} // namespace mongo
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