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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/sharding_ddl_coordinator_gen.h"
namespace mongo {
class ShardingDDLCoordinator;
class ShardingDDLCoordinatorService final : public repl::PrimaryOnlyService {
public:
static constexpr StringData kServiceName = "ShardingDDLCoordinator"_sd;
explicit ShardingDDLCoordinatorService(ServiceContext* serviceContext)
: PrimaryOnlyService(serviceContext) {}
~ShardingDDLCoordinatorService() = default;
static ShardingDDLCoordinatorService* getService(OperationContext* opCtx);
StringData getServiceName() const override {
return kServiceName;
}
NamespaceString getStateDocumentsNS() const override {
return NamespaceString::kShardingDDLCoordinatorsNamespace;
}
ThreadPool::Limits getThreadPoolLimits() const override {
ThreadPool::Limits limits;
limits.maxThreads = ThreadPool::Options::kUnlimited;
return 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;
std::shared_ptr<Instance> getOrCreateInstance(OperationContext* opCtx, BSONObj initialState);
std::shared_ptr<executor::TaskExecutor> getInstanceCleanupExecutor() const;
void waitForCoordinatorsOfGivenTypeToComplete(OperationContext* opCtx,
DDLCoordinatorTypeEnum type) const;
/**
* Waits for all currently running coordinators matching the predicate 'pred' to finish. While
* waiting here, new coordinators may start, but they will not be waited for.
*/
void waitForOngoingCoordinatorsToFinish(
OperationContext* opCtx,
std::function<bool(const ShardingDDLCoordinator&)> pred = {
[](const ShardingDDLCoordinator&) { return true; }});
private:
ExecutorFuture<void> _rebuildService(std::shared_ptr<executor::ScopedTaskExecutor> executor,
const CancellationToken& token) override;
void _waitForRecoveryCompletion(OperationContext* opCtx) const;
void _afterStepDown() override;
size_t _countCoordinatorDocs(OperationContext* opCtx);
mutable Mutex _mutex = MONGO_MAKE_LATCH("ShardingDDLCoordinatorService::_mutex");
// When the node stepDown the state is set to kPaused and all the new DDL operation will be
// blocked. On step-up we set _coordinatorsToWait to the numbers of coordinators that needs to
// be recovered and we enter in kRecovering state. Once all coordinators have been recovered we
// move to kRecovered state and we unblock all new incoming DDL.
enum class State {
kPaused,
kRecovering,
kRecovered,
};
State _state = State::kPaused;
mutable stdx::condition_variable _recoveredOrCoordinatorCompletedCV;
// This counter is set up at stepUp and reprensent the number of coordinator instances
// that needs to be recovered from disk.
size_t _numCoordinatorsToWait{0};
stdx::unordered_map<DDLCoordinatorTypeEnum, size_t> _numActiveCoordinatorsPerType;
};
} // namespace mongo
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