diff options
Diffstat (limited to 'src/mongo/db/vector_clock_mongod.cpp')
| -rw-r--r-- | src/mongo/db/vector_clock_mongod.cpp | 179 |
1 files changed, 179 insertions, 0 deletions
diff --git a/src/mongo/db/vector_clock_mongod.cpp b/src/mongo/db/vector_clock_mongod.cpp new file mode 100644 index 00000000000..69d2eb2e7c1 --- /dev/null +++ b/src/mongo/db/vector_clock_mongod.cpp @@ -0,0 +1,179 @@ +/** + * Copyright (C) 2020-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. + */ + +#include "mongo/platform/basic.h" + +#include "mongo/db/replica_set_aware_service.h" +#include "mongo/db/vector_clock_mutable.h" + +namespace mongo { +namespace { + +/** + * Vector clock implementation for mongod. + */ +class VectorClockMongoD : public VectorClockMutable, + public ReplicaSetAwareService<VectorClockMongoD> { + VectorClockMongoD(const VectorClockMongoD&) = delete; + VectorClockMongoD& operator=(const VectorClockMongoD&) = delete; + +public: + static VectorClockMongoD* get(ServiceContext* serviceContext); + + VectorClockMongoD(); + virtual ~VectorClockMongoD(); + + LogicalTime tick(Component component, uint64_t nTicks) override; + void tickTo(Component component, LogicalTime newTime) override; + +protected: + void _gossipOutInternal(BSONObjBuilder* out) const override; + void _gossipOutExternal(BSONObjBuilder* out) const override; + LogicalTimeArray _gossipInInternal(const BSONObj& in) override; + LogicalTimeArray _gossipInExternal(const BSONObj& in) override; + +private: + enum class ReplState { + Unset, + StepUpBegin, + StepUpComplete, + StepDown, + }; + + void onStepUpBegin(OperationContext* opCtx) override; + void onStepUpComplete(OperationContext* opCtx) override; + void onStepDown() override; + + ReplState _replState{ReplState::Unset}; +}; + +const auto vectorClockMongoDDecoration = ServiceContext::declareDecoration<VectorClockMongoD>(); + +const ReplicaSetAwareServiceRegistry::Registerer<VectorClockMongoD> vectorClockMongoDRegisterer( + "VectorClockMongoD-ReplicaSetAwareServiceRegistration"); + +VectorClockMongoD* VectorClockMongoD::get(ServiceContext* serviceContext) { + return &vectorClockMongoDDecoration(serviceContext); +} + +ServiceContext::ConstructorActionRegisterer _registerer( + "VectorClockMongoD-VectorClockRegistration", + {}, + [](ServiceContext* service) { + VectorClockMongoD::registerVectorClockOnServiceContext( + service, &vectorClockMongoDDecoration(service)); + }, + {}); + +VectorClockMongoD::VectorClockMongoD() = default; + +VectorClockMongoD::~VectorClockMongoD() = default; + +void VectorClockMongoD::onStepUpBegin(OperationContext* opCtx) { + _replState = ReplState::StepUpBegin; +} + +void VectorClockMongoD::onStepUpComplete(OperationContext* opCtx) { + _replState = ReplState::StepUpComplete; +} + +void VectorClockMongoD::onStepDown() { + _replState = ReplState::StepDown; +} + +void VectorClockMongoD::_gossipOutInternal(BSONObjBuilder* out) const { + VectorTime now = getTime(); + // TODO SERVER-47914: re-enable gossipping of VectorClock's ClusterTime once LogicalClock has + // been migrated into VectorClock. + // _gossipOutComponent(out, now, Component::ClusterTime); + if (serverGlobalParams.clusterRole == ClusterRole::ShardServer || + serverGlobalParams.clusterRole == ClusterRole::ConfigServer) { + _gossipOutComponent(out, now, Component::ConfigTime); + } +} + +void VectorClockMongoD::_gossipOutExternal(BSONObjBuilder* out) const { + // TODO SERVER-47914: re-enable gossipping of VectorClock's ClusterTime once LogicalClock has + // been migrated into VectorClock. + // VectorTime now = getTime(); + // _gossipOutComponent(out, now, Component::ClusterTime); +} + +VectorClock::LogicalTimeArray VectorClockMongoD::_gossipInInternal(const BSONObj& in) { + LogicalTimeArray newTime; + // TODO SERVER-47914: re-enable gossipping of VectorClock's ClusterTime once LogicalClock has + // been migrated into VectorClock. + // _gossipInComponent(in, &newTime, Component::ClusterTime); + if (serverGlobalParams.clusterRole == ClusterRole::ShardServer) { + _gossipInComponent(in, &newTime, Component::ConfigTime); + } + return newTime; +} + +VectorClock::LogicalTimeArray VectorClockMongoD::_gossipInExternal(const BSONObj& in) { + LogicalTimeArray newTime; + // TODO SERVER-47914: re-enable gossipping of VectorClock's ClusterTime once LogicalClock has + // been migrated into VectorClock. + // _gossipInComponent(in, &newTime, Component::ClusterTime); + return newTime; +} + +LogicalTime VectorClockMongoD::tick(Component component, uint64_t nTicks) { + if (component == Component::ClusterTime) { + // Although conceptually ClusterTime can only be ticked when a mongod is able to take writes + // (ie. primary, or standalone), this is handled at a higher layer. + // + // ClusterTime is ticked when replacing zero-valued Timestamps with the current time, which + // is usually but not necessarily associated with writes. + // + // ClusterTime is ticked after winning an election, while persisting the stepUp to the + // oplog, which is slightly before the repl state is changed to primary. + // + // As such, ticking ClusterTime is not restricted here based on repl state. + + return _advanceComponentTimeByTicks(component, nTicks); + } + + // tick is not permitted in other circumstances. + MONGO_UNREACHABLE; +} + +void VectorClockMongoD::tickTo(Component component, LogicalTime newTime) { + if (component == Component::ConfigTime && + serverGlobalParams.clusterRole == ClusterRole::ConfigServer) { + _advanceComponentTimeTo(component, std::move(newTime)); + return; + } + + // tickTo is not permitted in other circumstances. + MONGO_UNREACHABLE; +} + +} // namespace +} // namespace mongo |