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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.h"
#include "mongo/bson/bsonobj.h"
#include "mongo/db/namespace_string.h"
#include "mongo/db/pipeline/aggregation_request.h"
#include "mongo/db/pipeline/document_source.h"
#include "mongo/s/async_requests_sender.h"
#include "mongo/s/commands/strategy.h"
#include "mongo/s/query/cluster_client_cursor_params.h"
#include "mongo/s/query/document_source_merge_cursors.h"
namespace mongo {
class LiteParsedPipeline;
class OperationContext;
class ShardId;
/**
* Methods for running aggregation across a sharded cluster.
*/
class ClusterAggregate {
public:
/**
* Max number of retries to resolve the underlying namespace of a view.
*/
static constexpr unsigned kMaxViewRetries = 10;
/**
* '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 the aggregation 'request' using context 'opCtx'.
*
* The 'namespaces' struct should contain both the user-requested namespace and the namespace
* over which the aggregation will actually execute. Typically these two namespaces are the
* same, but they may differ in the case of a query on a view.
*
* 'privileges' contains the privileges that were required to run this aggregation, to be used
* later for re-checking privileges for GetMore commands.
*
* On success, fills out 'result' with the command response.
*/
static Status runAggregate(OperationContext* opCtx,
const Namespaces& namespaces,
const AggregationRequest& request,
const LiteParsedPipeline& liteParsedPipeline,
const PrivilegeVector& privileges,
BSONObjBuilder* result);
/**
* Convenience version that internally constructs the LiteParsedPipeline.
*/
static Status runAggregate(OperationContext* opCtx,
const Namespaces& namespaces,
const AggregationRequest& request,
const PrivilegeVector& privileges,
BSONObjBuilder* result);
/**
* Retries a command that was previously run on a view by resolving the view as an aggregation
* against the underlying collection.
*
* 'privileges' contains the privileges that were required to run this aggregation, to be used
* later for re-checking privileges for GetMore commands.
*
* On success, populates 'result' with the command response.
*/
static Status retryOnViewError(OperationContext* opCtx,
const AggregationRequest& request,
const ResolvedView& resolvedView,
const NamespaceString& requestedNss,
const PrivilegeVector& privileges,
BSONObjBuilder* result,
unsigned numberRetries = 0);
private:
static Status aggPassthrough(OperationContext*,
const Namespaces&,
const ShardId&,
const AggregationRequest&,
const LiteParsedPipeline&,
const PrivilegeVector& privileges,
BSONObjBuilder* result,
bool forPerShardCursor);
};
} // namespace mongo
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