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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.
*/
#include "mongo/platform/basic.h"
#include "mongo/db/query/sbe_sub_planner.h"
#include "mongo/db/query/collection_query_info.h"
#include "mongo/db/query/plan_cache_key_factory.h"
#include "mongo/db/query/query_planner.h"
#include "mongo/db/query/sbe_multi_planner.h"
#include "mongo/db/query/stage_builder_util.h"
#include "mongo/db/query/util/make_data_structure.h"
namespace mongo::sbe {
CandidatePlans SubPlanner::plan(
std::vector<std::unique_ptr<QuerySolution>> solutions,
std::vector<std::pair<std::unique_ptr<PlanStage>, stage_builder::PlanStageData>>) {
const auto& mainColl = _collections.getMainCollection();
// Plan each branch of the $or.
auto subplanningStatus = QueryPlanner::planSubqueries(
_opCtx, {} /* getSolutionCachedData */, mainColl, _cq, _queryParams);
if (!subplanningStatus.isOK()) {
return planWholeQuery();
}
auto multiplanCallback = [&](CanonicalQuery* cq,
std::vector<std::unique_ptr<QuerySolution>> solutions)
-> StatusWith<std::unique_ptr<QuerySolution>> {
// One of the indexes in '_queryParams' might have been dropped while planning a previous
// branch of the OR query. In this case, fail with a 'QueryPlanKilled' error.
_indexExistenceChecker.check(_opCtx, _collections);
// Ensure that no previous plans are registered to yield while we multi plan each branch.
_yieldPolicy->clearRegisteredPlans();
std::vector<std::pair<std::unique_ptr<PlanStage>, stage_builder::PlanStageData>> roots;
for (auto&& solution : solutions) {
roots.push_back(stage_builder::buildSlotBasedExecutableTree(
_opCtx, _collections, *cq, *solution, _yieldPolicy));
}
// Clear any plans registered to yield once multiplanning is done for this branch. We don't
// want to leave dangling pointers to the execution plans used in multi planning hanging
// around in the YieldPolicy.
ON_BLOCK_EXIT([this]() { _yieldPolicy->clearRegisteredPlans(); });
// We pass the SometimesCache option to the MPS because the SubplanStage currently does
// not use the 'CachedSolutionPlanner' eviction mechanism. We therefore are more
// conservative about putting a potentially bad plan into the cache in the subplan path.
MultiPlanner multiPlanner{
_opCtx, _collections, *cq, _queryParams, PlanCachingMode::SometimesCache, _yieldPolicy};
auto&& [candidates, winnerIdx] = multiPlanner.plan(std::move(solutions), std::move(roots));
invariant(winnerIdx < candidates.size());
return std::move(candidates[winnerIdx].solution);
};
auto subplanSelectStat = QueryPlanner::choosePlanForSubqueries(
_cq, _queryParams, std::move(subplanningStatus.getValue()), multiplanCallback);
// One of the indexes in '_queryParams' might have been dropped while planning the final branch
// of the OR query. In this case, fail with a 'QueryPlanKilled' error.
_indexExistenceChecker.check(_opCtx, _collections);
if (!subplanSelectStat.isOK()) {
// Query planning can continue if we failed to find a solution for one of the children.
// Otherwise, it cannot, as it may no longer be safe to access the collection (an index
// may have been dropped, we may have exceeded the time limit, etc).
uassert(4822874,
subplanSelectStat.getStatus().reason(),
subplanSelectStat == ErrorCodes::NoQueryExecutionPlans);
return planWholeQuery();
}
// Build a plan stage tree from a composite solution.
auto compositeSolution = std::move(subplanSelectStat.getValue());
// If some agg pipeline stages are being pushed down, extend the solution with them.
if (!_cq.pipeline().empty()) {
compositeSolution = QueryPlanner::extendWithAggPipeline(
_cq, std::move(compositeSolution), _queryParams.secondaryCollectionsInfo);
}
auto&& [root, data] = stage_builder::buildSlotBasedExecutableTree(
_opCtx, _collections, _cq, *compositeSolution, _yieldPolicy);
// Be careful to cache the plan before preparing or opening it. This will copy 'root' and 'data'
// into the cache in their pristine state. This is necessary since plans are currently
// re-prepared each time that they are recovered from the cache. The re-preparation step
// includes setting up the runtime environment and in particular getting a new "shardFilterer"
// value, as the "shardFilterer" must not be stored in the plan cache (doing so would block
// range deletion).
plan_cache_util::updatePlanCache(_opCtx, _collections, _cq, *compositeSolution, *root, data);
prepareExecutionPlan(root.get(), &data, false /*preparingFromCache*/);
root->open(false);
return {makeVector(plan_ranker::CandidatePlan{
std::move(compositeSolution), std::move(root), std::move(data)}),
0};
}
CandidatePlans SubPlanner::planWholeQuery() const {
// Use the query planning module to plan the whole query.
auto statusWithMultiPlanSolns = QueryPlanner::plan(_cq, _queryParams);
auto solutions = uassertStatusOK(std::move(statusWithMultiPlanSolns));
// Only one possible plan. Build the stages from the solution.
if (solutions.size() == 1) {
// If some agg pipeline stages are being pushed down, extend the solution with them.
if (!_cq.pipeline().empty()) {
solutions[0] = QueryPlanner::extendWithAggPipeline(
_cq, std::move(solutions[0]), _queryParams.secondaryCollectionsInfo);
}
auto&& [root, data] = stage_builder::buildSlotBasedExecutableTree(
_opCtx, _collections, _cq, *solutions[0], _yieldPolicy);
prepareExecutionPlan(root.get(), &data, false /*preparingFromCache*/);
root->open(false);
return {makeVector(plan_ranker::CandidatePlan{
std::move(solutions[0]), std::move(root), std::move(data)}),
0};
}
// Many solutions. Build a plan stage tree for each solution and create a multi planner to pick
// the best, update the cache, and so on.
std::vector<std::pair<std::unique_ptr<PlanStage>, stage_builder::PlanStageData>> roots;
for (auto&& solution : solutions) {
roots.push_back(stage_builder::buildSlotBasedExecutableTree(
_opCtx, _collections, _cq, *solution, _yieldPolicy));
}
MultiPlanner multiPlanner{
_opCtx, _collections, _cq, _queryParams, PlanCachingMode::AlwaysCache, _yieldPolicy};
return multiPlanner.plan(std::move(solutions), std::move(roots));
}
} // namespace mongo::sbe
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