324 lines
7.9 KiB
C++
324 lines
7.9 KiB
C++
/*
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1.1 \textit{CommunicationServer}
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The \textit{CommunicationServer} is the counterpart of the
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\textit{CommunicationClient}. Whenever communication associated with the
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\textit{DBService's} functionality takes place,
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the \textit{CommunicationServer} is contacted by a
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\textit{CommunicationClient}.
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The \textit{CommunicationServer} is deducted from the more generic class
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\textit{Server} of the \textit{Distributed2Algebra} which had to be extracted
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from the \textit{FileTransferServer} for this purpose. The second superclass
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of the \textit{CommunicationServer} is \textit{MultiClientServer}, as we only
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want to have one \textit{CommunicationServer} per node which is able to handle
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multiple client requests.
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----
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This file is part of SECONDO.
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Copyright (C) 2017,
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Faculty of Mathematics and Computer Science,
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Database Systems for New Applications.
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SECONDO is free software; you can redistribute it and/or modify
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it under the terms of the GNU General Public License as published by
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the Free Software Foundation; either version 2 of the License, or
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(at your option) any later version.
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SECONDO is distributed in the hope that it will be useful,
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but WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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GNU General Public License for more details.
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You should have received a copy of the GNU General Public License
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along with SECONDO; if not, write to the Free Software
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Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
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----
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*/
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#ifndef ALGEBRAS_DBSERVICE_CommunicationServer_HPP_
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#define ALGEBRAS_DBSERVICE_CommunicationServer_HPP_
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#include "Algebras/DBService/MultiClientServer.hpp"
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class Socket;
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namespace DBService
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{
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/*
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1.1.1 Class Definition
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*/
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class CommunicationServer: public MultiClientServer
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{
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/*
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1.1.1.1 Constructor
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*/
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public:
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explicit CommunicationServer(int port);
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/*
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1.1.1.1 Destructor
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*/
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virtual ~CommunicationServer();
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/*
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1.1.1.1 \textit{start}
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This function is called to start the ~CommunicationServer~
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*/
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int start();
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/*
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1.1.1.1 \textit{communicate}
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This function is called as soon as an incoming connection from a
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\textit{CommunicationClient} is detected. Based on the used keywords, it decides
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which function shall be executed.
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*/
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protected:
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int communicate(std::iostream& io);
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/*
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1.1.1.1 \textit{handleTriggerReplicationRequest}
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This function is executed when a \textit{CommunicationClient} on the original
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node of a relation requests its replication. The \textit{DBServiceManager} on
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the \textit{DBService} master node is contacted in order to determine suitable
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replica locations and if a sufficient number of worker nodes is available, the
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replication is triggered.
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*/
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bool handleStartingSignalRequest(
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std::iostream& io,
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const boost::thread::id tid);
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/*
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1.1.1.1 ~handleStartingSignalRequest~
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This function is executed when a \textit{CommunicationClient} on the original
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node of a relation gives the starting signal for the replication.
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The replication is triggered by notifying the ~DBService~ workers
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*/
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bool handleTriggerReplicationRequest(
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std::iostream& io,
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const boost::thread::id tid);
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/*
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1.1.1.1 \textit{handleTriggerFileTransferRequest}
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This function is executed when a \textit{CommunicationClient} residing on the
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\textit{DBService} master node requests triggering the file transfer between
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the \textit{DBService} worker node and the original node.
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A \textit{ReplicationClient} is instantiated that connects to the
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\textit{ReplicationServer} on the original node in order to request the file
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transfer.
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*/
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bool handleTriggerFileTransferRequest(
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std::iostream& io,
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const boost::thread::id tid);
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/*
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1.1.1.1 \textit{handleProvideReplicaLocationRequest}
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This function retrieves one of the replica locations from the
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\textit{DBServiceManager} on the \textit{DBService} master node and provides
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it to the connected \textit{CommunicationClient}.
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*/
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bool handleProvideReplicaLocationRequest(
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std::iostream& io,
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const boost::thread::id tid);
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/*
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1.1.1.1 \textit{reportSuccessfulReplication}
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This function notifies the \textit{DBServiceManager} on the \textit{DBService}
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master node so that the successful replication can be maintained in the
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corresponding mapping table.
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*/
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bool reportSuccessfulReplication(
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std::iostream& io,
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const boost::thread::id tid);
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/*
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1.1.1.1 \textit{handleRequestReplicaDeletion}
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This function retrieves all replica locations from the
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\textit{DBServiceManager} on the \textit{DBService} master node and initializes
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one \textit{CommunicationClient} for each worker node which triggers the
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deletion of the replica.
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*/
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bool handleRequestReplicaDeletion(
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std::iostream& io,
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const boost::thread::id tid);
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/*
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1.1.1.1 \textit{handleTriggerReplicaDeletion}
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This function triggers the deletion of a certain replica on the
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\textit{DBService} worker node where the \textit{CommunicationServer} is
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running.
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*/
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bool handleTriggerReplicaDeletion(
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std::iostream& io,
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const boost::thread::id tid);
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/*
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1.1.1.1 \textit{handlePing}
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This function triggers reacts on the ping of a client by sending a ping
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back.
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*/
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bool handlePing(
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std::iostream& io,
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const boost::thread::id tid);
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/*
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1.1.1.1 ~handleRelTypeRequest~
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This function provides the connected client with the type of a relation for
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which a replica is stored in the ~DBService~.
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*/
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bool handleRelTypeRequest(
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std::iostream& io,
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const boost::thread::id tid);
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/*
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1.1.1.1 ~handleDerivedTypeRequest~
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Retrieves the type of a derived object.
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*/
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bool handleDerivedTypeRequest(
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std::iostream& io,
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const boost::thread::id tid);
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/*
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1.1.1.1 ~handleTriggerDerivation~
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This function handles a triggerDerivation message.
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*/
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bool handleTriggerDerivation(
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std::iostream& io,
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const boost::thread::id tid);
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/*
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1.1.1.1 ~handleCreateDerivation~
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This function handles a triggerDerivation message.
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*/
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bool handleCreateDerivation(
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std::iostream& io,
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const boost::thread::id tid);
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/*
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1.1.1.1 ~reportSuccessfulDerivation~
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This function informs the dbservice manager about a
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successful derivation.
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*/
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bool reportSuccessfulDerivation(
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std::iostream& io,
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const boost::thread::id tid);
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/*
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1.1.1.1 \textit{lookupMinimumReplicaCount}
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This function retrieves the minimum number of replicas from the configuration
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file and stores it in the corresponding member variable.
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*/
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private:
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void lookupMinimumReplicaCount();
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/*
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1.1.1.1 \textit{minimumReplicaCount}
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One configuration parameter of the \textit{DBService} is the number of replicas
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that shall be available for each relation. As it does not make sense to read
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this information from the configuration file again every time a relation shall
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be replicated, each \textit{CommunicationServer} looks it up once during
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initialization. However, it is actually only used on the \textit{DBService}
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master node.
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*/
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int minimumReplicaCount;
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/*
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1.1.1.1 ~deleteRemoteDerivate~
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This function will trigger the deletion of a derivate on all dbservice-workers
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storing this derivate.
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*/
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void deleteRemoteDerivate(
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const std::string& databaseName,
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const std::string& relationName,
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const std::string& derivateName);
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/*
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1.1.1.1 ~deleteRemoteRelation~
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This fucntion triggers the deletion of a relation and all
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depending objects on all servers storing this relation.
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*/
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void deleteRemoteRelation(
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const std::string& databaseName,
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const std::string& relationName);
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/*
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1.1.1.1 ~deleteRemoteDatabase~
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This function triggers the deletion of all objects within a
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database on all workers storing this database.
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*/
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void deleteRemoteDatabase(const std::string& databaseName);
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};
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} /* namespace DBService */
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#endif /* ALGEBRAS_DBSERVICE_CommunicationServer_HPP_ */
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