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/**
* Copyright (C) 2014 MongoDB Inc.
*
* This program is free software: you can redistribute it and/or modify
* it under the terms of the GNU Affero General Public License, version 3,
* as published by the Free Software Foundation.
*
* 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
* GNU Affero General Public License for more details.
*
* You should have received a copy of the GNU Affero General Public License
* along with this program. If not, see <http://www.gnu.org/licenses/>.
*
* 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 GNU Affero General 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 <deque>
#include "mongo/base/disallow_copying.h"
#include "mongo/db/concurrency/d_concurrency.h"
#include "mongo/db/repl/bgsync.h"
#include "mongo/db/repl/replication_coordinator_external_state.h"
#include "mongo/db/repl/rs_sync.h"
#include "mongo/db/repl/sync_source_feedback.h"
#include "mongo/db/repl/sync_tail.h"
#include "mongo/db/repl/task_runner.h"
#include "mongo/db/storage/journal_listener.h"
#include "mongo/db/storage/snapshot_manager.h"
#include "mongo/stdx/mutex.h"
#include "mongo/util/concurrency/old_thread_pool.h"
namespace mongo {
class ServiceContext;
namespace repl {
namespace {
using UniqueLock = stdx::unique_lock<stdx::mutex>;
} // namespace
class SnapshotThread;
class StorageInterface;
class NoopWriter;
class ReplicationCoordinatorExternalStateImpl final : public ReplicationCoordinatorExternalState,
public JournalListener {
MONGO_DISALLOW_COPYING(ReplicationCoordinatorExternalStateImpl);
public:
ReplicationCoordinatorExternalStateImpl(StorageInterface* storageInterface);
virtual ~ReplicationCoordinatorExternalStateImpl();
virtual void startThreads(const ReplSettings& settings) override;
virtual void startInitialSync(OnInitialSyncFinishedFn finished) override;
virtual void startSteadyStateReplication(OperationContext* txn,
ReplicationCoordinator* replCoord) override;
virtual void stopDataReplication(OperationContext* txn) override;
virtual void runOnInitialSyncThread(stdx::function<void(OperationContext* txn)> run) override;
virtual bool isInitialSyncFlagSet(OperationContext* txn) override;
virtual void startMasterSlave(OperationContext* txn);
virtual void shutdown(OperationContext* txn);
virtual executor::TaskExecutor* getTaskExecutor() const override;
virtual OldThreadPool* getDbWorkThreadPool() const override;
virtual Status runRepairOnLocalDB(OperationContext* txn) override;
virtual Status initializeReplSetStorage(OperationContext* txn, const BSONObj& config);
void onDrainComplete(OperationContext* txn) override;
OpTime onTransitionToPrimary(OperationContext* txn, bool isV1ElectionProtocol) override;
virtual void forwardSlaveProgress();
virtual OID ensureMe(OperationContext* txn);
virtual bool isSelf(const HostAndPort& host, ServiceContext* ctx);
virtual StatusWith<BSONObj> loadLocalConfigDocument(OperationContext* txn);
virtual Status storeLocalConfigDocument(OperationContext* txn, const BSONObj& config);
virtual StatusWith<LastVote> loadLocalLastVoteDocument(OperationContext* txn);
virtual Status storeLocalLastVoteDocument(OperationContext* txn, const LastVote& lastVote);
virtual void setGlobalTimestamp(const Timestamp& newTime);
virtual StatusWith<OpTime> loadLastOpTime(OperationContext* txn);
virtual void cleanUpLastApplyBatch(OperationContext* txn);
virtual HostAndPort getClientHostAndPort(const OperationContext* txn);
virtual void closeConnections();
virtual void killAllUserOperations(OperationContext* txn);
virtual void shardingOnStepDownHook();
virtual void signalApplierToChooseNewSyncSource();
virtual void signalApplierToCancelFetcher();
void dropAllSnapshots() final;
void updateCommittedSnapshot(SnapshotName newCommitPoint) final;
void forceSnapshotCreation() final;
virtual bool snapshotsEnabled() const;
virtual void notifyOplogMetadataWaiters();
virtual double getElectionTimeoutOffsetLimitFraction() const;
virtual bool isReadCommittedSupportedByStorageEngine(OperationContext* txn) const;
virtual StatusWith<OpTime> multiApply(OperationContext* txn,
MultiApplier::Operations ops,
MultiApplier::ApplyOperationFn applyOperation) override;
virtual Status multiSyncApply(MultiApplier::OperationPtrs* ops) override;
virtual Status multiInitialSyncApply(MultiApplier::OperationPtrs* ops) override;
virtual void resetSyncSourceHostAndFetchCount(const HostAndPort& source) override;
virtual unsigned getApplierFetchCount() const override;
virtual std::unique_ptr<OplogBuffer> makeInitialSyncOplogBuffer(
OperationContext* txn) const override;
virtual std::unique_ptr<OplogBuffer> makeSteadyStateOplogBuffer(
OperationContext* txn) const override;
virtual bool shouldUseDataReplicatorInitialSync() const override;
virtual std::size_t getOplogFetcherMaxFetcherRestarts() const override;
// Methods from JournalListener.
virtual JournalListener::Token getToken();
virtual void onDurable(const JournalListener::Token& token);
virtual void setupNoopWriter(Seconds waitTime);
virtual void startNoopWriter(OpTime);
virtual void stopNoopWriter();
private:
/**
* Stops data replication and returns with 'lock' locked.
*/
void _stopDataReplication_inlock(OperationContext* txn, UniqueLock* lock);
/**
* Called when the instance transitions to primary in order to notify a potentially sharded host
* to perform respective state changes, such as starting the balancer, etc.
*
* Throws on errors.
*/
void _shardingOnTransitionToPrimaryHook(OperationContext* txn);
/**
* Drops all temporary collections on all databases except "local".
*
* The implementation may assume that the caller has acquired the global exclusive lock
* for "txn".
*/
void _dropAllTempCollections(OperationContext* txn);
// Guards starting threads and setting _startedThreads
stdx::mutex _threadMutex;
// Flag for guarding against concurrent data replication stopping.
bool _stoppingDataReplication = false;
stdx::condition_variable _dataReplicationStopped;
StorageInterface* _storageInterface;
// True when the threads have been started
bool _startedThreads = false;
// The SyncSourceFeedback class is responsible for sending replSetUpdatePosition commands
// for forwarding replication progress information upstream when there is chained
// replication.
SyncSourceFeedback _syncSourceFeedback;
// The BackgroundSync class is responsible for pulling ops off the network from the sync source
// and into a BlockingQueue.
// We can't create it on construction because it needs a fully constructed
// ReplicationCoordinator, but this ExternalState object is constructed prior to the
// ReplicationCoordinator.
std::unique_ptr<BackgroundSync> _bgSync;
// Thread running SyncSourceFeedback::run().
std::unique_ptr<stdx::thread> _syncSourceFeedbackThread;
// Thread running runSyncThread().
std::unique_ptr<RSDataSync> _applierThread;
// Mutex guarding the _nextThreadId value to prevent concurrent incrementing.
stdx::mutex _nextThreadIdMutex;
// Number used to uniquely name threads.
long long _nextThreadId = 0;
std::unique_ptr<SnapshotThread> _snapshotThread;
// Initial sync stuff
StartInitialSyncFn _startInitialSyncIfNeededFn;
StartSteadyReplicationFn _startSteadReplicationFn;
OldThreadPool _initialSyncThreadPool;
TaskRunner _initialSyncRunner;
// Task executor used to run replication tasks.
std::unique_ptr<executor::TaskExecutor> _taskExecutor;
// Used by repl::multiApply() to apply the sync source's operations in parallel.
std::unique_ptr<OldThreadPool> _writerPool;
// Used by repl::multiInitialSyncApply() to apply the sync source's operations.
// repl::multiInitialSyncApply uses SyncTail::shouldRetry() (and implicitly getMissingDoc())
// to fetch missing documents during initial sync. Therefore, it is fine to construct SyncTail
// with invalid BackgroundSync, MultiSyncApplyFunc and writerPool arguments because we will not
// be accessing any SyncTail functionality that require these constructor parameters.
SyncTail _syncTail;
// Writes a noop every 10 seconds.
std::unique_ptr<NoopWriter> _noopWriter;
};
} // namespace repl
} // namespace mongo
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