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/**
* Copyright (C) 2013 10gen 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/>.
*/
#pragma once
#include "mongo/db/clientcursor.h"
#include "mongo/db/query/canonical_query.h"
#include "mongo/db/query/lite_parsed_query.h"
#include "mongo/db/query/plan_cache.h"
#include "mongo/db/query/plan_executor.h"
#include "mongo/db/query/runner.h"
#include "mongo/db/query/stage_builder.h"
namespace mongo {
/**
* SingleSolutionRunner runs a plan that was the only possible solution to a query. It exists
* only to dump stats into the cache after running.
*/
class SingleSolutionRunner : public Runner {
public:
/**
* Takes ownership of both arguments.
*/
SingleSolutionRunner(CanonicalQuery* canonicalQuery, QuerySolution* soln,
PlanStage* root, WorkingSet* ws)
: _canonicalQuery(canonicalQuery), _solution(soln),
_exec(new PlanExecutor(ws, root)) { }
Runner::RunnerState getNext(BSONObj* objOut, DiskLoc* dlOut) {
return _exec->getNext(objOut, dlOut);
// TODO: I'm not convinced we want to cache this run. What if it's a collscan solution
// and the user adds an index later? We don't want to reach for this. But if solving
// the query is v. hard, we do want to cache it. Maybe we can remove single solution
// cache entries when we build an index?
}
virtual bool isEOF() { return _exec->isEOF(); }
virtual void saveState() { _exec->saveState(); }
virtual bool restoreState() { return _exec->restoreState(); }
virtual void setYieldPolicy(Runner::YieldPolicy policy) {
_exec->setYieldPolicy(policy);
}
virtual void invalidate(const DiskLoc& dl) { _exec->invalidate(dl); }
virtual const string& ns() { return _canonicalQuery->getParsed().ns(); }
virtual void kill() { _exec->kill(); }
private:
scoped_ptr<CanonicalQuery> _canonicalQuery;
scoped_ptr<QuerySolution> _solution;
scoped_ptr<PlanExecutor> _exec;
};
} // namespace mongo
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