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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 "mongo/db/pipeline/pipeline.h"
#include "mongo/s/async_requests_sender.h"
#include "mongo/s/catalog_cache.h"
#include "mongo/s/query/cluster_aggregation_planner.h"
namespace mongo {
class CachedCollectionRoutingInfo;
namespace sharded_agg_helpers {
struct DispatchShardPipelineResults {
// True if this pipeline was split, and the second half of the pipeline needs to be run on
// the primary shard for the database.
bool needsPrimaryShardMerge;
// Populated if this *is not* an explain, this vector represents the cursors on the remote
// shards.
std::vector<OwnedRemoteCursor> remoteCursors;
// Populated if this *is* an explain, this vector represents the results from each shard.
std::vector<AsyncRequestsSender::Response> remoteExplainOutput;
// The split version of the pipeline if more than one shard was targeted, otherwise
// boost::none.
boost::optional<cluster_aggregation_planner::SplitPipeline> splitPipeline;
// If the pipeline targeted a single shard, this is the pipeline to run on that shard.
std::unique_ptr<Pipeline, PipelineDeleter> pipelineForSingleShard;
// The command object to send to the targeted shards.
BSONObj commandForTargetedShards;
// How many exchange producers are running the shard part of splitPipeline.
size_t numProducers;
// The exchange specification if the query can run with the exchange otherwise boost::none.
boost::optional<cluster_aggregation_planner::ShardedExchangePolicy> exchangeSpec;
};
Shard::RetryPolicy getDesiredRetryPolicy(const AggregationRequest& req);
bool mustRunOnAllShards(const NamespaceString& nss, const LiteParsedPipeline& litePipe);
StatusWith<CachedCollectionRoutingInfo> getExecutionNsRoutingInfo(OperationContext* opCtx,
const NamespaceString& execNss);
/**
* Targets shards for the pipeline and returns a struct with the remote cursors or results, and the
* pipeline that will need to be executed to merge the results from the remotes. If a stale shard
* version is encountered, refreshes the routing table and tries again.
*/
DispatchShardPipelineResults dispatchShardPipeline(
const boost::intrusive_ptr<ExpressionContext>& expCtx,
const NamespaceString& executionNss,
const AggregationRequest& aggRequest,
const LiteParsedPipeline& liteParsedPipeline,
std::unique_ptr<Pipeline, PipelineDeleter> pipeline,
BSONObj collationObj);
std::set<ShardId> getTargetedShards(OperationContext* opCtx,
bool mustRunOnAllShards,
const boost::optional<CachedCollectionRoutingInfo>& routingInfo,
const BSONObj shardQuery,
const BSONObj collation);
std::vector<RemoteCursor> establishShardCursors(
OperationContext* opCtx,
const NamespaceString& nss,
const LiteParsedPipeline& litePipe,
boost::optional<CachedCollectionRoutingInfo>& routingInfo,
const std::set<ShardId>& shardIds,
const BSONObj& cmdObj,
const AggregationRequest& request,
const ReadPreferenceSetting& readPref);
BSONObj createCommandForTargetedShards(
OperationContext* opCtx,
const AggregationRequest& request,
const LiteParsedPipeline& litePipe,
const cluster_aggregation_planner::SplitPipeline& splitPipeline,
const BSONObj collationObj,
const boost::optional<cluster_aggregation_planner::ShardedExchangePolicy> exchangeSpec,
const boost::optional<RuntimeConstants>& constants,
bool needsMerge);
BSONObj createPassthroughCommandForShard(OperationContext* opCtx,
const AggregationRequest& request,
const boost::optional<RuntimeConstants>& constants,
Pipeline* pipeline,
BSONObj collationObj,
bool forPerShardCursor,
boost::optional<int> overrideBatchSize);
BSONObj genericTransformForShards(MutableDocument&& cmdForShards,
OperationContext* opCtx,
const AggregationRequest& request,
const boost::optional<RuntimeConstants>& constants,
BSONObj collationObj,
bool forPerShardCursor = false);
/**
* For a sharded collection, establishes remote cursors on each shard that may have results, and
* creates a DocumentSourceMergeCursors stage to merge the remove cursors. Returns a pipeline
* beginning with that DocumentSourceMergeCursors stage. Note that one of the 'remote' cursors might
* be this node itself.
*/
std::unique_ptr<Pipeline, PipelineDeleter> targetShardsAndAddMergeCursors(
const boost::intrusive_ptr<ExpressionContext>& expCtx, Pipeline* ownedPipeline);
} // namespace sharded_agg_helpers
} // namespace mongo
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