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/**
* Copyright (C) 2020-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/bson/bsonobj.h"
#include "mongo/db/exec/plan_stage.h"
#include "mongo/db/query/plan_enumerator_explain_info.h"
#include "mongo/db/query/plan_explainer.h"
#include "mongo/db/query/query_solution.h"
#include "mongo/util/duration.h"
namespace mongo {
/**
* A PlanExplainer implementation for classic execution plans.
*
* For classic execution plans all information required to generate explain output in various
* formats is stored in the execution tree itself, so having access to the root stage of the
* execution tree this PlanExplainer should obtain all plan details and execution stats.
*/
class PlanExplainerImpl final : public PlanExplainer {
public:
PlanExplainerImpl(PlanStage* root, const PlanEnumeratorExplainInfo& explainInfo)
: PlanExplainer{explainInfo}, _root{root} {}
PlanExplainerImpl(PlanStage* root) : _root{root} {}
const ExplainVersion& getVersion() const final;
bool isMultiPlan() const final;
std::string getPlanSummary() const final;
void getSummaryStats(PlanSummaryStats* statsOut) const final;
PlanStatsDetails getWinningPlanStats(ExplainOptions::Verbosity verbosity) const final;
PlanStatsDetails getWinningPlanTrialStats() const final;
std::vector<PlanStatsDetails> getRejectedPlansStats(
ExplainOptions::Verbosity verbosity) const final;
std::vector<PlanStatsDetails> getCachedPlanStats(const plan_cache_debug_info::DebugInfo&,
ExplainOptions::Verbosity) const;
private:
PlanStage* const _root;
};
/**
* Retrieves the first stage of a given type from the plan tree, or nullptr if no such stage is
* found.
*/
PlanStage* getStageByType(PlanStage* root, StageType type);
/**
* Returns filtered plan stats from the debugInfo object for different verbosity levels.
*/
std::vector<PlanExplainer::PlanStatsDetails> getCachedPlanStats(
const plan_cache_debug_info::DebugInfo& debugInfo, ExplainOptions::Verbosity verbosity);
/**
* Adds the path-level multikey information to the explain output in a field called "multiKeyPaths".
* The value associated with the "multiKeyPaths" field is an object with keys equal to those in the
* index key pattern and values equal to an array of strings corresponding to paths that cause the
* index to be multikey.
*
* For example, with the index {'a.b': 1, 'a.c': 1} where the paths "a" and "a.b" cause the
* index to be multikey, we'd have {'multiKeyPaths': {'a.b': ['a', 'a.b'], 'a.c': ['a']}}.
*
* This function should only be called if the associated index supports path-level multikey
* tracking.
*/
void appendMultikeyPaths(const BSONObj& keyPattern,
const MultikeyPaths& multikeyPaths,
BSONObjBuilder* bob);
} // namespace mongo
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