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/**
* 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/collection.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"
#include "mongo/db/ops/update_result.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. If the prior or
* newly-updated version of the document was requested to be returned, then ADVANCED is
* returned after updating or inserting a document. Otherwise, NEED_TIME is returned after
* updating or inserting a document.
*
* Callers of work() must be holding a write lock.
*/
class UpdateStage final : public PlanStage {
MONGO_DISALLOW_COPYING(UpdateStage);
public:
UpdateStage(OperationContext* txn,
const UpdateStageParams& params,
WorkingSet* ws,
Collection* collection,
PlanStage* child);
bool isEOF() final;
StageState work(WorkingSetID* out) final;
void doRestoreState() final;
StageType stageType() const final {
return STAGE_UPDATE;
}
std::unique_ptr<PlanStageStats> getStats() final;
const SpecificStats* getSpecificStats() const final;
static const char* kStageType;
/**
* Converts the execution stats (stored by the update stage as an UpdateStats) for the
* update plan represented by 'exec' into the UpdateResult format used to report the results
* of writes.
*
* Also responsible for filling out 'opDebug' with execution info.
*
* Should only be called once this stage is EOF.
*/
static UpdateResult makeUpdateResult(const PlanExecutor& exec, OpDebug* opDebug);
/**
* Computes the document to insert if the upsert flag is set to true and no matching
* documents are found in the database. The document to upsert is computing using the
* query 'cq' and the update mods contained in 'driver'.
*
* If 'cq' is NULL, which can happen for the idhack update fast path, then 'query' is
* used to compute the doc to insert instead of 'cq'.
*
* 'doc' is the mutable BSON document which you would like the update driver to use
* when computing the document to insert.
*
* Set 'isInternalRequest' to true if the upsert was issued by the replication or
* sharding systems.
*
* Fills out whether or not this is a fastmodinsert in 'stats'.
*
* Returns the document to insert in *out.
*/
static Status applyUpdateOpsForInsert(const CanonicalQuery* cq,
const BSONObj& query,
UpdateDriver* driver,
UpdateLifecycle* lifecycle,
mutablebson::Document* doc,
bool isInternalRequest,
UpdateStats* stats,
BSONObj* out);
private:
/**
* Computes the result of applying mods to the document 'oldObj' at RecordId 'loc' in
* memory, then commits these changes to the database. Returns a possibly unowned copy
* of the newly-updated version of the document.
*/
BSONObj transformAndUpdate(const Snapshotted<BSONObj>& oldObj, RecordId& 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();
/**
* Helper for restoring the state of this update.
*/
Status restoreUpdateState();
UpdateStageParams _params;
// Not owned by us.
WorkingSet* _ws;
// Not owned by us. May be NULL.
Collection* _collection;
// If not WorkingSet::INVALID_ID, we use this rather than asking our child what to do next.
WorkingSetID _idRetrying;
// If not WorkingSet::INVALID_ID, we return this member to our caller.
WorkingSetID _idReturning;
// Stats
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<RecordId, RecordId::Hasher> DiskLocSet;
const std::unique_ptr<DiskLocSet> _updatedLocs;
// These get reused for each update.
mutablebson::Document& _doc;
mutablebson::DamageVector _damages;
};
} // namespace mongo
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