SERVER-14497 UpdateStage

1 files changed, 164 insertions, 0 deletions

diff --git a/src/mongo/db/exec/update.h b/src/mongo/db/exec/update.h
new file mode 100644
index 00000000000..862074e4001
--- /dev/null
+++ b/src/mongo/db/exec/update.h
@@ -0,0 +1,164 @@
+/**
+ *    Copyright (C) 2014 MongoDB 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/>.
+ *
+ *    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 GNU Affero General 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/db/catalog/database.h"
+#include "mongo/db/exec/plan_stage.h"
+#include "mongo/db/jsobj.h"
+#include "mongo/db/ops/update_driver.h"
+#include "mongo/db/ops/update_request.h"
+
+namespace mongo {
+
+    class OperationContext;
+
+    struct UpdateStageParams {
+
+        UpdateStageParams(const UpdateRequest* r,
+                          UpdateDriver* d,
+                          OpDebug* o)
+            : request(r),
+              driver(d),
+              opDebug(o),
+              canonicalQuery(NULL) { }
+
+        // Contains update parameters like whether it's a multi update or an upsert. Not owned.
+        // Must outlive the UpdateStage.
+        const UpdateRequest* request;
+
+        // Contains the logic for applying mods to documents. Not owned. Must outlive
+        // the UpdateStage.
+        UpdateDriver* driver;
+
+        // Needed to pass to Collection::updateDocument(...).
+        OpDebug* opDebug;
+
+        // Not owned here.
+        CanonicalQuery* canonicalQuery;
+
+    private:
+        // Default constructor not allowed.
+        UpdateStageParams();
+    };
+
+    /**
+     * Execution stage responsible for updates to documents and upserts. NEED_TIME is returned
+     * after performing an update or an insert.
+     *
+     * Callers of work() must be holding a write lock.
+     */
+    class UpdateStage : public PlanStage {
+        MONGO_DISALLOW_COPYING(UpdateStage);
+    public:
+        UpdateStage(const UpdateStageParams& params,
+                    WorkingSet* ws,
+                    Database* db,
+                    PlanStage* child);
+
+        virtual bool isEOF();
+        virtual StageState work(WorkingSetID* out);
+
+        virtual void saveState();
+        virtual void restoreState(OperationContext* opCtx);
+        virtual void invalidate(const DiskLoc& dl, InvalidationType type);
+
+        virtual std::vector<PlanStage*> getChildren() const;
+
+        virtual StageType stageType() const { return STAGE_UPDATE; }
+
+        virtual PlanStageStats* getStats();
+
+        virtual const CommonStats* getCommonStats();
+
+        virtual const SpecificStats* getSpecificStats();
+
+        static const char* kStageType;
+
+    private:
+        /**
+         * Computes the result of applying mods to the document 'oldObj' at DiskLoc 'loc' in
+         * memory, then commits these changes to the database.
+         */
+        void transformAndUpdate(BSONObj& oldObj, DiskLoc& loc);
+
+        /**
+         * Computes the document to insert and inserts it into the collection. Used if the
+         * user requested an upsert and no matching documents were found.
+         */
+        void doInsert();
+
+        /**
+         * Have we performed all necessary updates? Even if this is true, we might not be EOF,
+         * as we might still have to do an insert.
+         */
+        bool doneUpdating();
+
+        /**
+         * Examines the stats / update request and returns whether there is still an insert left
+         * to do. If so then this stage is not EOF yet.
+         */
+        bool needInsert();
+
+        UpdateStageParams _params;
+
+        // Not owned by us.
+        WorkingSet* _ws;
+
+        // Not owned by us.
+        Database* _db;
+        Collection* _collection;
+
+        // Owned by us.
+        scoped_ptr<PlanStage> _child;
+
+        // Stats
+        CommonStats _commonStats;
+        UpdateStats _specificStats;
+
+        // If the update was in-place, we may see it again.  This only matters if we're doing
+        // a multi-update; if we're not doing a multi-update we stop after one update and we
+        // won't see any more docs.
+        //
+        // For example: If we're scanning an index {x:1} and performing {$inc:{x:5}}, we'll keep
+        // moving the document forward and it will continue to reappear in our index scan.
+        // Unless the index is multikey, the underlying query machinery won't de-dup.
+        //
+        // If the update wasn't in-place we may see it again.  Our query may return the new
+        // document and we wouldn't want to update that.
+        //
+        // So, no matter what, we keep track of where the doc wound up.
+        typedef unordered_set<DiskLoc, DiskLoc::Hasher> DiskLocSet;
+        const boost::scoped_ptr<DiskLocSet> _updatedLocs;
+
+        // These get reused for each update.
+        mutablebson::Document& _doc;
+        mutablebson::DamageVector _damages;
+    };
+
+}  // namespace mongo