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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 <deque>
#include "mongo/db/concurrency/d_concurrency.h"
#include "mongo/db/repl/bgsync.h"
#include "mongo/db/repl/oplog_applier.h"
#include "mongo/db/repl/replication_coordinator_external_state.h"
#include "mongo/db/repl/sync_source_feedback.h"
#include "mongo/db/repl/task_runner.h"
#include "mongo/db/storage/journal_listener.h"
#include "mongo/db/storage/snapshot_manager.h"
#include "mongo/platform/mutex.h"
#include "mongo/util/concurrency/thread_pool.h"
namespace mongo {
class ServiceContext;
namespace repl {
class DropPendingCollectionReaper;
class ReplicationProcess;
class StorageInterface;
class NoopWriter;
class ReplicationCoordinatorExternalStateImpl final : public ReplicationCoordinatorExternalState,
public JournalListener {
ReplicationCoordinatorExternalStateImpl(const ReplicationCoordinatorExternalStateImpl&) =
delete;
ReplicationCoordinatorExternalStateImpl& operator=(
const ReplicationCoordinatorExternalStateImpl&) = delete;
public:
ReplicationCoordinatorExternalStateImpl(
ServiceContext* service,
DropPendingCollectionReaper* dropPendingCollectionReaper,
StorageInterface* storageInterface,
ReplicationProcess* replicationProcess);
virtual ~ReplicationCoordinatorExternalStateImpl();
virtual void startThreads(const ReplSettings& settings) override;
virtual void startSteadyStateReplication(OperationContext* opCtx,
ReplicationCoordinator* replCoord) override;
virtual void stopDataReplication(OperationContext* opCtx) override;
virtual bool isInitialSyncFlagSet(OperationContext* opCtx) override;
virtual void shutdown(OperationContext* opCtx);
virtual void clearAppliedThroughIfCleanShutdown(OperationContext* opCtx);
virtual executor::TaskExecutor* getTaskExecutor() const override;
virtual ThreadPool* getDbWorkThreadPool() const override;
virtual Status initializeReplSetStorage(OperationContext* opCtx, const BSONObj& config);
void onDrainComplete(OperationContext* opCtx) override;
OpTime onTransitionToPrimary(OperationContext* opCtx) override;
virtual void forwardSlaveProgress();
virtual bool isSelf(const HostAndPort& host, ServiceContext* service);
Status createLocalLastVoteCollection(OperationContext* opCtx) final;
virtual StatusWith<BSONObj> loadLocalConfigDocument(OperationContext* opCtx);
virtual Status storeLocalConfigDocument(OperationContext* opCtx, const BSONObj& config);
virtual StatusWith<LastVote> loadLocalLastVoteDocument(OperationContext* opCtx);
virtual Status storeLocalLastVoteDocument(OperationContext* opCtx, const LastVote& lastVote);
virtual void setGlobalTimestamp(ServiceContext* service, const Timestamp& newTime);
virtual Timestamp getGlobalTimestamp(ServiceContext* service);
bool oplogExists(OperationContext* opCtx) final;
virtual StatusWith<OpTimeAndWallTime> loadLastOpTimeAndWallTime(OperationContext* opCtx);
virtual HostAndPort getClientHostAndPort(const OperationContext* opCtx);
virtual void closeConnections();
virtual void shardingOnStepDownHook();
virtual void clearOplogVisibilityStateForStepDown() override;
virtual void signalApplierToChooseNewSyncSource();
virtual void stopProducer();
virtual void startProducerIfStopped();
virtual bool tooStale();
void dropAllSnapshots() final;
void updateCommittedSnapshot(const OpTime& newCommitPoint) final;
void updateLocalSnapshot(const OpTime& optime) final;
virtual bool snapshotsEnabled() const;
virtual void notifyOplogMetadataWaiters(const OpTime& committedOpTime);
boost::optional<OpTime> getEarliestDropPendingOpTime() const final;
virtual double getElectionTimeoutOffsetLimitFraction() const;
virtual bool isReadCommittedSupportedByStorageEngine(OperationContext* opCtx) const;
virtual bool isReadConcernSnapshotSupportedByStorageEngine(OperationContext* opCtx) const;
virtual std::size_t getOplogFetcherSteadyStateMaxFetcherRestarts() const override;
virtual std::size_t getOplogFetcherInitialSyncMaxFetcherRestarts() 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* opCtx, stdx::unique_lock<Latch>& 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* opCtx);
/**
* Drops all temporary collections on all databases except "local".
*
* The implementation may assume that the caller has acquired the global exclusive lock
* for "opCtx".
*/
void _dropAllTempCollections(OperationContext* opCtx);
ServiceContext* _service;
// Guards starting threads and setting _startedThreads
Mutex _threadMutex = MONGO_MAKE_LATCH("ReplicationCoordinatorExternalStateImpl::_threadMutex");
// Flag for guarding against concurrent data replication stopping.
bool _stoppingDataReplication = false;
stdx::condition_variable _dataReplicationStopped;
// Used to clean up drop-pending collections with drop optimes before the current replica set
// committed OpTime.
DropPendingCollectionReaper* _dropPendingCollectionReaper;
StorageInterface* _storageInterface;
ReplicationProcess* _replicationProcess;
// True when the threads have been started
bool _startedThreads = false;
// Set to true when we are in the process of shutting down replication.
bool _inShutdown = false;
// The SyncSourceFeedback class is responsible for sending replSetUpdatePosition commands
// for forwarding replication progress information upstream when there is chained
// replication.
SyncSourceFeedback _syncSourceFeedback;
// The OplogBuffer is used to hold operations read from the sync source. During oplog
// application, Backgrounds Sync adds operations to the OplogBuffer while the applier's
// OplogBatcher consumes these operations from the buffer in batches.
std::unique_ptr<OplogBuffer> _oplogBuffer;
// 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 oplog application.
std::unique_ptr<executor::TaskExecutor> _oplogApplierTaskExecutor;
std::unique_ptr<OplogApplier> _oplogApplier;
Future<void> _oplogApplierShutdownFuture;
// Mutex guarding the _nextThreadId value to prevent concurrent incrementing.
Mutex _nextThreadIdMutex =
MONGO_MAKE_LATCH("ReplicationCoordinatorExternalStateImpl::_nextThreadIdMutex");
// Number used to uniquely name threads.
long long _nextThreadId = 0;
// Task executor used to run replication tasks.
std::unique_ptr<executor::TaskExecutor> _taskExecutor;
// Used by repl::applyOplogBatch() to apply the sync source's operations in parallel.
// Also used by database and collection cloners to perform storage operations.
// Cloners and oplog application run in separate phases of initial sync so it is fine to share
// this thread pool.
std::unique_ptr<ThreadPool> _writerPool;
// Writes a noop every 10 seconds.
std::unique_ptr<NoopWriter> _noopWriter;
};
} // namespace repl
} // namespace mongo
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