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/**
* 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.
*/
#pragma once
#include "mongo/db/repl/primary_only_service.h"
#include "mongo/db/s/resharding/recipient_document_gen.h"
#include "mongo/db/s/resharding/resharding_oplog_applier.h"
#include "mongo/db/s/resharding/resharding_oplog_fetcher.h"
#include "mongo/s/resharding/type_collection_fields_gen.h"
#include "mongo/util/concurrency/thread_pool.h"
namespace mongo {
class ReshardingCollectionCloner;
namespace resharding {
/**
* Creates the temporary resharding collection locally by loading the collection options and
* collection indexes from the original collection's primary and MinKey owning chunk shards,
* respectively.
*/
void createTemporaryReshardingCollectionLocally(OperationContext* opCtx,
const NamespaceString& originalNss,
const NamespaceString& reshardingNss,
const UUID& reshardingUUID,
const UUID& existingUUID,
Timestamp fetchTimestamp);
std::vector<NamespaceString> ensureStashCollectionsExist(
OperationContext* opCtx,
const ChunkManager& cm,
const UUID& existingUUID,
std::vector<DonorShardMirroringEntry> donorShards);
} // namespace resharding
class ReshardingRecipientService final : public repl::PrimaryOnlyService {
public:
static constexpr StringData kServiceName = "ReshardingRecipientService"_sd;
explicit ReshardingRecipientService(ServiceContext* serviceContext)
: PrimaryOnlyService(serviceContext) {}
~ReshardingRecipientService() = default;
class RecipientStateMachine;
StringData getServiceName() const override {
return kServiceName;
}
NamespaceString getStateDocumentsNS() const override {
return NamespaceString::kRecipientReshardingOperationsNamespace;
}
ThreadPool::Limits getThreadPoolLimits() const override {
// TODO Limit the size of ReshardingRecipientService thread pool.
return ThreadPool::Limits();
}
std::shared_ptr<PrimaryOnlyService::Instance> constructInstance(
BSONObj initialState) const override;
};
/**
* Represents the current state of a resharding recipient operation on this shard. This class
* drives state transitions and updates to underlying on-disk metadata.
*/
class ReshardingRecipientService::RecipientStateMachine final
: public repl::PrimaryOnlyService::TypedInstance<RecipientStateMachine> {
public:
explicit RecipientStateMachine(const BSONObj& recipientDoc);
~RecipientStateMachine();
SemiFuture<void> run(std::shared_ptr<executor::ScopedTaskExecutor> executor,
const CancelationToken& token) noexcept override;
void interrupt(Status status) override;
/**
* Returns a Future that will be resolved when all work associated with this Instance has
* completed running.
*/
SharedSemiFuture<void> getCompletionFuture() const {
return _completionPromise.getFuture();
}
boost::optional<BSONObj> reportForCurrentOp(
MongoProcessInterface::CurrentOpConnectionsMode,
MongoProcessInterface::CurrentOpSessionsMode) noexcept override;
void onReshardingFieldsChanges(const TypeCollectionReshardingFields& reshardingFields);
private:
// The following functions correspond to the actions to take at a particular recipient state.
void _transitionToCreatingTemporaryReshardingCollection();
void _createTemporaryReshardingCollectionThenTransitionToCloning();
ExecutorFuture<void> _cloneThenTransitionToApplying(
const std::shared_ptr<executor::ScopedTaskExecutor>& executor,
const CancelationToken& cancelToken);
void _applyThenTransitionToSteadyState();
ExecutorFuture<void> _awaitAllDonorsMirroringThenTransitionToStrictConsistency(
const std::shared_ptr<executor::ScopedTaskExecutor>& executor);
ExecutorFuture<void> __awaitCoordinatorHasDecisionPersistedThenTransitionToRenaming(
const std::shared_ptr<executor::ScopedTaskExecutor>& executor);
void _renameTemporaryReshardingCollection();
void _fulfillAllDonorsPreparedToDonate(Timestamp);
// Transitions the state on-disk and in-memory to 'endState'.
void _transitionState(RecipientStateEnum endState,
boost::optional<Timestamp> fetchTimestamp = boost::none,
boost::optional<Status> abortReason = boost::none);
void _transitionStateAndUpdateCoordinator(RecipientStateEnum endState,
boost::optional<Status> abortReason = boost::none);
// Inserts 'doc' on-disk and sets '_replacementDoc' in-memory.
void _insertRecipientDocument(const ReshardingRecipientDocument& doc);
// Updates the recipient document on-disk and in-memory with the 'replacementDoc.'
void _updateRecipientDocument(ReshardingRecipientDocument&& replacementDoc);
// Removes the local recipient document from disk and clears the in-memory state.
void _removeRecipientDocument();
// Removes any docs from the oplog applier progress and txn applier progress collections that
// are associated with the in-progress operation. Also drops all oplog buffer collections and
// all conflict stash collections that are associated with the in-progress operation.
void _dropOplogCollections(OperationContext* opCtx);
// The in-memory representation of the underlying document in
// config.localReshardingOperations.recipient.
ReshardingRecipientDocument _recipientDoc;
// The id both for the resharding operation and for the primary-only-service instance.
const UUID _id;
std::unique_ptr<ReshardingCollectionCloner> _collectionCloner;
std::vector<std::unique_ptr<ReshardingOplogApplier>> _oplogAppliers;
std::vector<std::unique_ptr<ThreadPool>> _oplogApplierWorkers;
// The ReshardingOplogFetcher must be destructed before the corresponding ReshardingOplogApplier
// to ensure the future returned by awaitInsert() is always eventually readied.
std::vector<std::unique_ptr<ReshardingOplogFetcher>> _oplogFetchers;
std::shared_ptr<executor::TaskExecutor> _oplogFetcherExecutor;
std::vector<ExecutorFuture<void>> _oplogFetcherFutures;
// Protects the promises below
Mutex _mutex = MONGO_MAKE_LATCH("ReshardingRecipient::_mutex");
// Each promise below corresponds to a state on the recipient state machine. They are listed in
// ascending order, such that the first promise below will be the first promise fulfilled.
SharedPromise<void> _coordinatorHasDecisionPersisted;
SharedPromise<void> _completionPromise;
};
} // namespace mongo
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