int rank(int key) { return ranking(root,key); }
bool MultiPlanRunner::pickBestPlan(size_t* out) { static const int timesEachPlanIsWorked = 100; // Run each plan some number of times. for (int i = 0; i < timesEachPlanIsWorked; ++i) { bool moreToDo = workAllPlans(); if (!moreToDo) { break; } } if (_failure || _killed) { return false; } auto_ptr<PlanRankingDecision> ranking(new PlanRankingDecision()); size_t bestChild = PlanRanker::pickBestPlan(_candidates, ranking.get()); // Run the best plan. Store it. _bestPlan.reset(new PlanExecutor(_candidates[bestChild].ws, _candidates[bestChild].root)); _bestPlan->setYieldPolicy(_policy); _alreadyProduced = _candidates[bestChild].results; _bestSolution.reset(_candidates[bestChild].solution); QLOG() << "Winning solution:\n" << _bestSolution->toString() << endl; size_t backupChild = bestChild; if (_bestSolution->hasSortStage && (0 == _alreadyProduced.size())) { QLOG() << "Winner has blocked sort, looking for backup plan...\n"; for (size_t i = 0; i < _candidates.size(); ++i) { if (!_candidates[i].solution->hasSortStage) { QLOG() << "Candidate " << i << " is backup child\n"; backupChild = i; _backupSolution = _candidates[i].solution; _backupAlreadyProduced = _candidates[i].results; _backupPlan = new PlanExecutor(_candidates[i].ws, _candidates[i].root); _backupPlan->setYieldPolicy(_policy); break; } } } // Store the choice we just made in the cache. if (PlanCache::shouldCacheQuery(*_query)) { Database* db = cc().database(); verify(NULL != db); Collection* collection = db->getCollection(_query->ns()); verify(NULL != collection); PlanCache* cache = collection->infoCache()->getPlanCache(); // Create list of candidate solutions for the cache with // the best solution at the front. std::vector<QuerySolution*> solutions; solutions.push_back(_bestSolution.get()); for (size_t i = 0; i < _candidates.size(); ++i) { if (i == bestChild) { continue; } solutions.push_back(_candidates[i].solution); } // Check solution cache data. Do not add to cache if // we have any invalid SolutionCacheData data. // XXX: One known example is 2D queries bool validSolutions = true; for (size_t i = 0; i < solutions.size(); ++i) { if (NULL == solutions[i]->cacheData.get()) { QLOG() << "Not caching query because this solution has no cache data: " << solutions[i]->toString(); validSolutions = false; break; } } if (validSolutions) { cache->add(*_query, solutions, ranking.release()); } } // Clear out the candidate plans, leaving only stats as we're all done w/them. for (size_t i = 0; i < _candidates.size(); ++i) { if (i == bestChild) { continue; } if (i == backupChild) { continue; } delete _candidates[i].solution; // Remember the stats for the candidate plan because we always show it on an // explain. (The {verbose:false} in explain() is client-side trick; we always // generate a "verbose" explain.) PlanStageStats* stats = _candidates[i].root->getStats(); if (stats) { _candidateStats.push_back(stats); } delete _candidates[i].root; // ws must die after the root. delete _candidates[i].ws; } _candidates.clear(); if (NULL != out) { *out = bestChild; } return true; }