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/**
* Copyright (C) 2018-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 <memory>
#include <vector>
#include "mongo/base/status_with.h"
#include "mongo/base/string_data.h"
#include "mongo/s/catalog/type_chunk.h"
#include "mongo/s/catalog/type_collection.h"
#include "mongo/s/catalog/type_database.h"
#include "mongo/s/chunk_version.h"
#include "mongo/s/type_collection_common_types_gen.h"
#include "mongo/util/concurrency/notification.h"
#include "mongo/util/uuid.h"
namespace mongo {
/**
* Interface through which the sharding catalog cache requests the set of changed chunks to be
* retrieved from the persisted metadata store.
*/
class CatalogCacheLoader {
public:
virtual ~CatalogCacheLoader() = default;
/**
* Stores a loader on the specified service context. May only be called once for the lifetime of
* the service context.
*/
static void set(ServiceContext* serviceContext, std::unique_ptr<CatalogCacheLoader> loader);
static CatalogCacheLoader& get(ServiceContext* serviceContext);
static CatalogCacheLoader& get(OperationContext* opCtx);
/**
* Used as a return value for getChunksSince.
*/
struct CollectionAndChangedChunks {
CollectionAndChangedChunks();
CollectionAndChangedChunks(
OID collEpoch,
Timestamp collCreationTime,
UUID uuid,
const BSONObj& collShardKeyPattern,
const BSONObj& collDefaultCollation,
bool collShardKeyIsUnique,
boost::optional<TypeCollectionTimeseriesFields> collTimeseriesFields,
boost::optional<TypeCollectionReshardingFields> collReshardingFields,
boost::optional<int64_t> maxChunkSizeBytes,
bool allowAutoSplit,
bool allowMigrations,
SupportingLongNameStatusEnum supportingLongName,
std::vector<ChunkType> chunks);
// Information about the entire collection
OID epoch;
Timestamp creationTime;
boost::optional<UUID> uuid; // This value can never be boost::none,
// except under the default constructor
BSONObj shardKeyPattern;
BSONObj defaultCollation;
bool shardKeyIsUnique;
// This information will be valid if the collection is a time-series buckets collection.
boost::optional<TypeCollectionTimeseriesFields> timeseriesFields;
// If the collection is currently undergoing a resharding operation, the optional will be
// populated.
boost::optional<TypeCollectionReshardingFields> reshardingFields;
boost::optional<int64_t> maxChunkSizeBytes;
bool allowAutoSplit;
bool allowMigrations;
SupportingLongNameStatusEnum supportingLongName;
// The chunks which have changed sorted by their chunkVersion. This list might potentially
// contain all the chunks in the collection.
std::vector<ChunkType> changedChunks;
};
using GetChunksSinceCallbackFn =
std::function<void(OperationContext*, StatusWith<CollectionAndChangedChunks>)>;
/**
* Initializes internal state. Must be called only once when sharding state is initialized.
*/
virtual void initializeReplicaSetRole(bool isPrimary) = 0;
/**
* Changes internal state on step down.
*/
virtual void onStepDown() = 0;
/**
* Changes internal state on step up.
*/
virtual void onStepUp() = 0;
/**
* Transitions into shut down and cleans up state. Once this transitions to shut down, should
* not be able to transition back to normal. Should be safe to be called more than once.
*/
virtual void shutDown() = 0;
/**
* Notifies the loader that the persisted collection version for 'nss' has been updated.
*/
virtual void notifyOfCollectionVersionUpdate(const NamespaceString& nss) = 0;
/**
* Non-blocking call, which returns the chunks changed since the specified version to be
* fetched from the persistent metadata store.
*
* If for some reason the asynchronous fetch operation cannot be dispatched (for example on
* shutdown), throws a DBException.
*/
virtual SemiFuture<CollectionAndChangedChunks> getChunksSince(const NamespaceString& nss,
ChunkVersion version) = 0;
/**
* Non-blocking call, which returns the most recent db version for the given dbName from the
* the persistent metadata store.
*
* If for some reason the asynchronous fetch operation cannot be dispatched (for example on
* shutdown), throws a DBException.
*/
virtual SemiFuture<DatabaseType> getDatabase(StringData dbName) = 0;
/**
* Waits for any pending changes for the specified collection to be persisted locally (not
* necessarily replicated). If newer changes come after this method has started running, they
* will not be waited for except if there is a drop.
*
* May throw if the node steps down from primary or if the operation time is exceeded or due to
* any other error condition.
*
* If the specific loader implementation does not support persistence, this method is undefined
* and must fassert.
*/
virtual void waitForCollectionFlush(OperationContext* opCtx, const NamespaceString& nss) = 0;
virtual void waitForDatabaseFlush(OperationContext* opCtx, StringData dbName) = 0;
/**
* Only used for unit-tests, clears a previously-created catalog cache loader from the specified
* service context, so that 'create' can be called again.
*/
static void clearForTests(ServiceContext* serviceContext);
protected:
CatalogCacheLoader() = default;
};
} // namespace mongo
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