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/**
* Copyright (C) 2016 MongoDB Inc.
*
* This program is free software: you can redistribute it and/or modify
* it under the terms of the GNU Affero General Public License, version 3,
* as published by the Free Software Foundation.
*
* 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
* GNU Affero General Public License for more details.
*
* You should have received a copy of the GNU Affero General Public License
* along with this program. If not, see <http://www.gnu.org/licenses/>.
*
* 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 GNU Affero General 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.h"
#include "mongo/bson/bsonobj.h"
#include "mongo/db/namespace_string.h"
#include "mongo/db/pipeline/document_source.h"
#include "mongo/db/pipeline/document_source_merge_cursors.h"
#include "mongo/s/commands/strategy.h"
#include "mongo/s/config.h"
namespace mongo {
class OperationContext;
/**
* Methods for running aggregation across a sharded cluster.
*/
class ClusterAggregate {
public:
/**
* 'requestedNss' is the namespace aggregation will register cursors under. This is the
* namespace which we will return in responses to aggregate / getMore commands, and it is the
* namespace we expect users to hand us inside any subsequent getMores. 'executionNss' is the
* namespace we will run the mongod aggregate and subsequent getMore's against.
*/
struct Namespaces {
NamespaceString requestedNss;
NamespaceString executionNss;
};
/**
* Executes an aggregation command. 'cmdObj' specifies the aggregation to run. Fills in 'result'
* with the command response.
*/
static Status runAggregate(OperationContext* opCtx,
const Namespaces& namespaces,
BSONObj cmdObj,
int options,
BSONObjBuilder* result);
private:
static std::vector<DocumentSourceMergeCursors::CursorDescriptor> parseCursors(
const std::vector<Strategy::CommandResult>& shardResults);
static void killAllCursors(const std::vector<Strategy::CommandResult>& shardResults);
static void uassertAllShardsSupportExplain(
const std::vector<Strategy::CommandResult>& shardResults);
// These are temporary hacks because the runCommand method doesn't report the exact
// host the command was run on which is necessary for cursor support. The exact host
// could be different from conn->getServerAddress() for connections that map to
// multiple servers such as for replica sets. These also take care of registering
// returned cursors.
static BSONObj aggRunCommand(OperationContext* opCtx,
DBClientBase* conn,
const Namespaces& namespaces,
BSONObj cmd,
int queryOptions);
static Status aggPassthrough(OperationContext* opCtx,
const Namespaces& namespaces,
DBConfig* conf,
BSONObj cmd,
BSONObjBuilder* result,
int queryOptions);
};
} // namespace mongo
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