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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 "mongo/db/pipeline/pipeline.h"
#include "mongo/s/catalog_cache.h"
#include "mongo/s/query/cluster_aggregate.h"
#include "mongo/s/query/cluster_client_cursor_guard.h"
#include "mongo/s/query/cluster_client_cursor_impl.h"
#include "mongo/s/query/cluster_client_cursor_params.h"
namespace mongo {
namespace cluster_aggregation_planner {
/**
* Builds a ClusterClientCursor which will execute 'pipeline'. If 'pipeline' consists entirely of
* $skip and $limit stages, the pipeline is eliminated entirely and replaced with a RouterExecStage
* tree that does same thing but will avoid using a RouterStagePipeline. Avoiding a
* RouterStagePipeline will remove an expensive conversion from BSONObj -> Document for each result.
*/
ClusterClientCursorGuard buildClusterCursor(OperationContext* opCtx,
std::unique_ptr<Pipeline, PipelineDeleter> pipeline,
ClusterClientCursorParams&&);
/**
* Returns the "collation" and "uuid" for the collection given by "nss" with the following
* semantics:
* - The "collation" parameter will be set to the default collation for the collection or the
* simple collation if there is no default. If the collection does not exist or if the aggregate
* is on the collectionless namespace, this will be set to an empty object.
* - The "uuid" is retrieved from the chunk manager for sharded collections or the listCollections
* output for unsharded collections. The UUID will remain unset if the aggregate is on the
* collectionless namespace.
*/
std::pair<BSONObj, boost::optional<UUID>> getCollationAndUUID(
OperationContext* opCtx,
const boost::optional<ChunkManager>& cm,
const NamespaceString& nss,
const BSONObj& collation);
/**
* This structure contains information for targeting an aggregation pipeline in a sharded cluster.
*/
struct AggregationTargeter {
/**
* Populates and returns targeting info for an aggregation pipeline on the given namespace
* 'executionNss'.
*/
static AggregationTargeter make(
OperationContext* opCtx,
const NamespaceString& executionNss,
std::function<std::unique_ptr<Pipeline, PipelineDeleter>()> buildPipelineFn,
boost::optional<CollectionRoutingInfo> cri,
stdx::unordered_set<NamespaceString> involvedNamespaces,
bool hasChangeStream,
bool startsWithDocuments,
bool allowedToPassthrough,
bool perShardCursor);
enum TargetingPolicy {
kPassthrough,
kMongosRequired,
kAnyShard,
kSpecificShardOnly,
} policy;
std::unique_ptr<Pipeline, PipelineDeleter> pipeline;
boost::optional<CollectionRoutingInfo> cri;
};
/**
* Runs a pipeline on the primary shard. See 'runPipelineOnSpecificShardOnly' for more details.
*/
Status runPipelineOnPrimaryShard(const boost::intrusive_ptr<ExpressionContext>& expCtx,
const ClusterAggregate::Namespaces& namespaces,
const ChunkManager& cm,
boost::optional<ExplainOptions::Verbosity> explain,
Document serializedCommand,
const PrivilegeVector& privileges,
bool eligibleForSampling,
BSONObjBuilder* out);
/**
* Runs a pipeline on mongoS, having first validated that it is eligible to do so. This can be a
* pipeline which is split for merging, or an intact pipeline which must run entirely on mongoS.
*/
Status runPipelineOnMongoS(const ClusterAggregate::Namespaces& namespaces,
long long batchSize,
std::unique_ptr<Pipeline, PipelineDeleter> pipeline,
BSONObjBuilder* result,
const PrivilegeVector& privileges);
/**
* Dispatches the pipeline in 'targeter' to the shards that are involved, and merges the results if
* necessary on either mongos or a randomly designated shard. If 'eligibleForSampling' is true,
* attaches a unique sample id to the request for one of the targeted shards if the collection has
* query sampling enabled and the rate-limited sampler successfully generates a sample id for it.
*/
Status dispatchPipelineAndMerge(OperationContext* opCtx,
AggregationTargeter targeter,
Document serializedCommand,
long long batchSize,
const ClusterAggregate::Namespaces& namespaces,
const PrivilegeVector& privileges,
BSONObjBuilder* result,
bool hasChangeStream,
bool startsWithDocuments,
bool eligibleForSampling);
/**
* Runs a pipeline on a specific shard. Used for running a pipeline on the primary shard (i.e. by
* 'runPipelineOnPrimaryShard') and on a specifc shard (i.e. by per shard $changeStream cursors).
* If 'forPerShardCursor' is true shard versions will not be added to the request sent to mongod.
* If 'eligibleForSampling' is true, attaches a unique sample id to the request for that shard if
* the collection has query sampling enabled and the rate-limited sampler successfully generates a
* sample id for it.
*/
Status runPipelineOnSpecificShardOnly(const boost::intrusive_ptr<ExpressionContext>& expCtx,
const ClusterAggregate::Namespaces& namespaces,
boost::optional<DatabaseVersion> dbVersion,
boost::optional<ExplainOptions::Verbosity> explain,
Document serializedCommand,
const PrivilegeVector& privileges,
ShardId shardId,
bool forPerShardCursor,
bool eligibleForSampling,
BSONObjBuilder* out);
} // namespace cluster_aggregation_planner
} // namespace mongo
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