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/**
* Copyright (C) 2022-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/s/move_primary_coordinator_document_gen.h"
#include "mongo/db/s/sharding_ddl_coordinator.h"
#include "mongo/s/client/shard.h"
namespace mongo {
class MovePrimaryCoordinator final
: public RecoverableShardingDDLCoordinator<MovePrimaryCoordinatorDocument,
MovePrimaryCoordinatorPhaseEnum> {
public:
using StateDoc = MovePrimaryCoordinatorDocument;
using Phase = MovePrimaryCoordinatorPhaseEnum;
MovePrimaryCoordinator(ShardingDDLCoordinatorService* service, const BSONObj& initialState);
virtual ~MovePrimaryCoordinator() = default;
void checkIfOptionsConflict(const BSONObj& doc) const override;
bool canAlwaysStartWhenUserWritesAreDisabled() const override;
private:
StringData serializePhase(const Phase& phase) const override;
void appendCommandInfo(BSONObjBuilder* cmdInfoBuilder) const override;
bool _mustAlwaysMakeProgress() override;
ExecutorFuture<void> _runImpl(std::shared_ptr<executor::ScopedTaskExecutor> executor,
const CancellationToken& token) noexcept override;
ExecutorFuture<void> _cleanupOnAbort(std::shared_ptr<executor::ScopedTaskExecutor> executor,
const CancellationToken& token,
const Status& status) noexcept override;
ExecutorFuture<void> runMovePrimaryWorkflow(
std::shared_ptr<executor::ScopedTaskExecutor> executor,
const CancellationToken& token) noexcept;
/**
* Logs in the `config.changelog` collection a specific event for `movePrimary` operations.
*/
void logChange(OperationContext* opCtx,
const std::string& what,
const Status& status = Status::OK()) const;
/**
* Returns the list of unsharded collections for the given database. These are the collections
* the recipient is expected to clone.
*/
std::vector<NamespaceString> getUnshardedCollections(OperationContext* opCtx);
/**
* Ensures that there are no orphaned collections in the recipient's catalog data, asserting
* otherwise.
*/
void assertNoOrphanedDataOnRecipient(
OperationContext* opCtx, const std::vector<NamespaceString>& collectionsToClone) const;
/**
* Requests to the recipient to clone all the collections of the given database currently owned
* by this shard. Once the cloning is complete, the recipient returns the list of the actually
* cloned collections.
*/
std::vector<NamespaceString> cloneDataToRecipient(OperationContext* opCtx) const;
/**
* Ensures that the list of actually cloned collections (returned by the cloning command)
* matches the list of collections to clone (persisted in the coordinator document).
*/
void assertClonedData(const std::vector<NamespaceString>& clonedCollections) const;
/**
* Commits the new primary shard for the given database to the config server. The database
* version is passed to the config server's command as an idempotency key.
*/
void commitMetadataToConfig(OperationContext* opCtx,
const DatabaseVersion& preCommitDbVersion) const;
/**
* Ensures that the metadata changes have been actually commited on the config server, asserting
* otherwise. This is a pedantic check to rule out any potentially disastrous problems.
*/
void assertChangedMetadataOnConfig(OperationContext* opCtx,
const DatabaseVersion& preCommitDbVersion) const;
/**
* Clears the database metadata in the local catalog cache. Secondary nodes clear the database
* metadata as a result of exiting the critical section of the primary node
* (`kExitCriticalSection` phase).
*/
void clearDbMetadataOnPrimary(OperationContext* opCtx) const;
/**
* Drops stale collections on the donor.
*/
void dropStaleDataOnDonor(OperationContext* opCtx) const;
/**
* Drops possible orphaned collections on the recipient.
*/
void dropOrphanedDataOnRecipient(OperationContext* opCtx,
std::shared_ptr<executor::ScopedTaskExecutor> executor);
/**
* Blocks write operations on the database, causing them to fail with the
* `MovePrimaryInProgress` error.
*
* TODO (SERVER-71566): This is a synchronization mechanism specifically designed for
* `movePrimary` operations. It will likely be replaced by the critical section once the time
* frame in which writes are blocked is reduced. Writes are already blocked in the `kCatchup`
* phase.
*/
void blockWritesLegacy(OperationContext* opCtx) const;
/**
* Unblocks write operations on the database.
*
* TODO (SERVER-71566): This is a synchronization mechanism specifically designed for
* `movePrimary` operations. It will likely be replaced by the critical section once the time
* frame in which writes are blocked is reduced. Reads and writes are already unblocked in the
// `kExitCriticalSection` phase.
*/
void unblockWritesLegacy(OperationContext* opCtx) const;
/**
* Blocks write operations on the database, causing them to wait until the critical section has
* entered.
*/
void blockWrites(OperationContext* opCtx) const;
/**
* Blocks read operations on the database, causing them to wait until the critical section has
* entered.
*/
void blockReads(OperationContext* opCtx) const;
/**
* Unblocks read and write operations on the database.
*/
void unblockReadsAndWrites(OperationContext* opCtx) const;
/**
* Requests the recipient to enter the critical section on the database, causing the database
* metadata refreshes to block.
*/
void enterCriticalSectionOnRecipient(OperationContext* opCtx) const;
/**
* Requests the recipient to exit the critical section on the database, causing the database
* metadata refreshes to unblock.
*/
void exitCriticalSectionOnRecipient(OperationContext* opCtx) const;
const DatabaseName _dbName;
const BSONObj _csReason;
};
} // namespace mongo
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