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/**
* Copyright (C) 2021-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/namespace_string.h"
#include "mongo/db/repl/primary_only_service.h"
#include "mongo/db/s/sharded_rename_collection_gen.h"
namespace mongo {
class RenameCollectionParticipantService final : public repl::PrimaryOnlyService {
public:
static constexpr StringData kServiceName = "RenameCollectionParticipantService"_sd;
explicit RenameCollectionParticipantService(ServiceContext* serviceContext)
: PrimaryOnlyService(serviceContext) {}
~RenameCollectionParticipantService() = default;
static RenameCollectionParticipantService* getService(OperationContext* opCtx);
StringData getServiceName() const override {
return kServiceName;
}
NamespaceString getStateDocumentsNS() const override {
return NamespaceString::kShardingRenameParticipantsNamespace;
}
ThreadPool::Limits getThreadPoolLimits() const override {
return ThreadPool::Limits();
}
// The service implemented its own conflict check before this method was added.
void checkIfConflictsWithOtherInstances(
OperationContext* opCtx,
BSONObj initialState,
const std::vector<const PrimaryOnlyService::Instance*>& existingInstances) override{};
std::shared_ptr<Instance> constructInstance(BSONObj initialState) override;
};
/*
* POS instance managing a rename operation on a single node.
*
* At a higher level, a rename operation corresponds to 2 steps.
* - STEP 1 (upon receiving `ShardsvrRenameCollectionParticipantCommand`):
* -- Block CRUD operations, drop target and rename source collection.
*
* - STEP 2 (Upon receiving `ShardsvrRenameCollectionUnblockParticipantCommand`):
* -- Unblock CRUD operations.
*
*/
class RenameParticipantInstance
: public repl::PrimaryOnlyService::TypedInstance<RenameParticipantInstance> {
public:
using StateDoc = RenameCollectionParticipantDocument;
using Phase = RenameCollectionParticipantPhaseEnum;
explicit RenameParticipantInstance(const BSONObj& participantDoc)
: _doc(RenameCollectionParticipantDocument::parse(
IDLParserContext("RenameCollectionParticipantDocument"), participantDoc)),
_request(_doc.getRenameCollectionRequest()) {}
~RenameParticipantInstance();
/*
* Check if the given participant document has the same options as the current instance.
* If it does, the participant can be joined.
*/
bool hasSameOptions(const BSONObj& participantDoc);
BSONObj doc() {
return _doc.toBSON();
}
const NamespaceString& fromNss() {
return _doc.getFromNss();
}
const UUID& sourceUUID() {
return _doc.getSourceUUID();
}
const NamespaceString& toNss() {
return _doc.getTo();
}
/*
* Returns a future that will be ready when the local rename is completed.
*/
SharedSemiFuture<void> getBlockCRUDAndRenameCompletionFuture() {
return _blockCRUDAndRenameCompletionPromise.getFuture();
}
/*
* Flags CRUD operations as ready to be served and returns a future that will be ready right
* after releasing the critical section on source and target collection.
*/
SharedSemiFuture<void> getUnblockCrudFuture() {
stdx::lock_guard<Latch> lg(_mutex);
if (!_canUnblockCRUDPromise.getFuture().isReady()) {
_canUnblockCRUDPromise.setFrom(Status::OK());
}
return _unblockCRUDPromise.getFuture();
}
boost::optional<BSONObj> reportForCurrentOp(
MongoProcessInterface::CurrentOpConnectionsMode connMode,
MongoProcessInterface::CurrentOpSessionsMode sessionMode) noexcept override;
void checkIfOptionsConflict(const BSONObj& stateDoc) const override {}
private:
RenameCollectionParticipantDocument _doc;
const RenameCollectionRequest _request;
SemiFuture<void> run(std::shared_ptr<executor::ScopedTaskExecutor> executor,
const CancellationToken& token) noexcept override final;
SemiFuture<void> _runImpl(std::shared_ptr<executor::ScopedTaskExecutor> executor,
const CancellationToken& token) noexcept;
void interrupt(Status status) noexcept override final;
template <typename Func>
auto _buildPhaseHandler(const Phase& newPhase, Func&& handlerFn) {
return [=] {
const auto& currPhase = _doc.getPhase();
if (currPhase > newPhase) {
// Do not execute this phase if we already reached a subsequent one.
return;
}
if (currPhase < newPhase) {
// Persist the new phase if this is the first time we are executing it.
_enterPhase(newPhase);
}
return handlerFn();
};
}
void _removeStateDocument(OperationContext* opCtx);
void _enterPhase(Phase newPhase);
void _invalidateFutures(const Status& errStatus);
Mutex _mutex = MONGO_MAKE_LATCH("RenameParticipantInstance::_mutex");
// Ready when step 1 (drop target && rename source) has been completed: once set, a successful
// response to `ShardsvrRenameCollectionParticipantCommand` can be returned to the coordinator.
SharedPromise<void> _blockCRUDAndRenameCompletionPromise;
// Ready when the "unblock CRUD" command has been received: once set, the participant POS can
// proceed to unblock CRUD operations.
SharedPromise<void> _canUnblockCRUDPromise;
// Ready when step 2 (unblock CRUD operations) have been completed: once set, a successful
// response to `ShardsvrRenameCollectionUnblockParticipantCommand` can be returned to the
// coordinator.
SharedPromise<void> _unblockCRUDPromise;
};
} // namespace mongo
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