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Diffstat (limited to 'src/mongo/db/s/resharding/resharding_coordinator_observer.h')
| -rw-r--r-- | src/mongo/db/s/resharding/resharding_coordinator_observer.h | 163 |
1 files changed, 163 insertions, 0 deletions
diff --git a/src/mongo/db/s/resharding/resharding_coordinator_observer.h b/src/mongo/db/s/resharding/resharding_coordinator_observer.h new file mode 100644 index 00000000000..df637cb96c4 --- /dev/null +++ b/src/mongo/db/s/resharding/resharding_coordinator_observer.h @@ -0,0 +1,163 @@ +/** + * 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 <vector> + +#include "mongo/base/status.h" +#include "mongo/bson/timestamp.h" +#include "mongo/db/s/resharding/coordinator_document_gen.h" +#include "mongo/platform/mutex.h" +#include "mongo/util/future.h" +#include "mongo/util/string_map.h" + +namespace mongo { + +class ChunkType; +class NamespaceString; +class OperationContext; +class ServiceContext; +class ShardId; + +/** + * Observes writes that indicate state changes for a resharding operation. Holds promises that + * the ReshardingCoordinator waits on in order to transition to a new state. + * + * An instance of this object is specific to one resharding operation. + */ + +class ReshardingCoordinatorObserver { +public: + ReshardingCoordinatorObserver(); + ~ReshardingCoordinatorObserver(); + + /** + * Called when each recipient updates its 'state' field to 'initializing' in the + * 'recipientShards' field in a config.reshardingOperations entry. + */ + void onRecipientReportsCreatedCollection(const ShardId& recipient); + + /** + * Called when each donor updates its 'state' field to 'donating' and writes its + * 'minFetchTimestamp' in the 'donorShards' field in a config.reshardingOperations entry. + */ + void onDonorReportsMinFetchTimestamp(const ShardId& donor, Timestamp timestamp); + + /** + * Called when each recipient updates its 'state' field to 'steady-state' in the + * 'recipientShards' field in a config.reshardingOperations entry. + */ + void onRecipientFinishesCloning(const ShardId& recipient); + + /** + * Called when each recipient updates its 'state' field to 'strictly-consistent' and writes its + * 'strictConsistencyTimestamp' in the 'recipientShards' field in a config.reshardingOperations + * entry. + */ + void onRecipientReportsStrictlyConsistent(const ShardId& recipient); + + /** + * Called when each recipient updates its 'state' field to 'done' in the 'recipientShards' + * field in a config.reshardingOperations entry. + */ + void onRecipientRenamesCollection(const ShardId& recipient); + + /** + * Called when each donor updates its 'state' field to 'done' in the 'donorShards' field in + * a config.reshardingOperations entry. + */ + void onDonorDropsOriginalCollection(const ShardId& donor); + + /** + * Called if a recipient reports an unrecoverable error. + */ + void onRecipientReportsUnrecoverableError(const ShardId& recipient, Status error); + + /** + * Fulfills the '_allRecipientsCreatedCollection' promise when the last recipient writes that it + * is in 'initializing' state. + */ + SharedSemiFuture<void> awaitAllRecipientsCreatedCollection(); + + /** + * When the last donor reports its 'minFetchTimestamp', selects the highest 'minFetchTimestamp' + * of all donors to be the 'fetchTimestamp'. Fulfills the '_allDonorsReportedMinFetchTimestamp' + * promise with this 'fetchTimestamp'. + */ + SharedSemiFuture<Timestamp> awaitAllDonorsReadyToDonate(); + + /** + * Fulfills the '_allRecipientsFinishedCloning' promise when the last recipient writes that it + * is in 'steady-state'. + */ + SharedSemiFuture<void> awaitAllRecipientsFinishedCloning(); + + /** + * Fulfills the '_allRecipientsReportedStrictConsistencyTimestamp' promise when the last + * recipient writes that it is in 'strict-consistency' state as well as its + * 'strictConsistencyTimestamp'. + */ + SharedSemiFuture<void> awaitAllRecipientsInStrictConsistency(); + + /** + * Fulfills the '_allDonorsDroppedOriginalCollection' promise when the last donor writes that it + * is in 'done' state. + */ + SharedSemiFuture<void> awaitAllDonorsDroppedOriginalCollection(); + + /** + * Fulfills the '_allRecipientsRenamedCollection' promise when the last recipient writes + * that it is in 'done' state. + */ + SharedSemiFuture<void> awaitAllRecipientsRenamedCollection(); + + +private: + // Protects the state below + Mutex _mutex = MONGO_MAKE_LATCH("ReshardingCoordinatorObserver::_mutex"); + + /** + * Promises indicating that either all donors or all recipients have entered a specific state. + * The ReshardingCoordinator waits on these in order to transition states. + */ + SharedPromise<void> _allRecipientsCreatedCollection; + + SharedPromise<Timestamp> _allDonorsReportedMinFetchTimestamp; + + SharedPromise<void> _allRecipientsFinishedCloning; + + SharedPromise<void> _allRecipientsReportedStrictConsistencyTimestamp; + + SharedPromise<void> _allDonorsDroppedOriginalCollection; + + SharedPromise<void> _allRecipientsRenamedCollection; +}; + +} // namespace mongo |