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diff --git a/src/mongo/db/query/cached_plan_runner.h b/src/mongo/db/query/cached_plan_runner.h
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+++ b/src/mongo/db/query/cached_plan_runner.h
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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/query/canonical_query.h"
+#include "mongo/db/query/plan_cache.h"
+#include "mongo/db/query/runner.h"
+#include "mongo/db/query/simple_plan_runner.h"
+#include "mongo/db/query/stage_builder.h"
+
+namespace mongo {
+
+    /**
+     * CachedPlanRunner runs a plan retrieved from the cache.
+     *
+     * Cached plans are bundled with information describing why the plan is in the cache.
+     *
+     * If we run a plan from the cache and behavior wildly deviates from expected behavior, we may
+     * remove the plan from the cache.  See plan_cache.h.
+     */
+    class CachedPlanRunner : public Runner {
+    public:
+        /**
+         * Takes ownership of both arguments.
+         */
+        CachedPlanRunner(CanonicalQuery* canonicalQuery, CachedSolution* cached,
+                         PlanStage* root, WorkingSet* ws)
+            : _canonicalQuery(canonicalQuery), _cachedQuery(cached),
+              _runner(new SimplePlanRunner(ws, root)) { }
+
+        bool getNext(BSONObj* objOut) {
+            // Use the underlying runner until it's exhausted.
+            if (_runner->getNext(objOut)) {
+                return true;
+            }
+
+            // We're done.  Update the cache.
+            PlanCache* cache = PlanCache::get(_canonicalQuery->ns());
+
+            // TODO: is this a verify?
+            if (NULL == cache) { return false; }
+
+            // TODO: How do we decide this?
+            bool shouldRemovePlan = false;
+
+            if (shouldRemovePlan) {
+                if (!cache->remove(*_canonicalQuery, *_cachedQuery->solution)) {
+                    warning() << "Cached plan runner couldn't remove plan from cache.  Maybe"
+                                 " somebody else did already?";
+                }
+                return false;
+            }
+
+            // We're done running.  Update cache.
+            auto_ptr<CachedSolutionFeedback> feedback(new CachedSolutionFeedback());
+            feedback->stats = _runner->getStats();
+            cache->feedback(*_canonicalQuery, *_cachedQuery->solution, feedback.release());
+            return false;
+        }
+
+    private:
+        scoped_ptr<CanonicalQuery> _canonicalQuery;
+        scoped_ptr<CachedSolution> _cachedQuery;
+        scoped_ptr<SimplePlanRunner> _runner;
+    };
+
+}  // namespace mongo