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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/exec/plan_stage.h"
#include "mongo/db/jsobj.h"
namespace mongo {
class CanonicalQuery;
class OpDebug;
class OperationContext;
class PlanExecutor;
struct DeleteStageParams {
DeleteStageParams()
: isMulti(false),
fromMigrate(false),
isExplain(false),
returnDeleted(false),
canonicalQuery(nullptr),
opDebug(nullptr) {}
// Should we delete all documents returned from the child (a "multi delete"), or at most one
// (a "single delete")?
bool isMulti;
// Is this delete part of a migrate operation that is essentially like a no-op
// when the cluster is observed by an external client.
bool fromMigrate;
// Are we explaining a delete command rather than actually executing it?
bool isExplain;
// Should we return the document we just deleted?
bool returnDeleted;
// The parsed query predicate for this delete. Not owned here.
CanonicalQuery* canonicalQuery;
// The user-requested sort specification. Currently used just for findAndModify.
BSONObj sort;
// Optional. When not null, delete metrics are recorded here.
OpDebug* opDebug;
};
/**
* This stage delete documents by RecordId that are returned from its child. If the deleted
* document was requested to be returned, then ADVANCED is returned after deleting a document.
* Otherwise, NEED_TIME is returned after deleting a document.
*
* Callers of work() must be holding a write lock (and, for replicated deletes, callers must have
* had the replication coordinator approve the write).
*/
class DeleteStage final : public PlanStage {
MONGO_DISALLOW_COPYING(DeleteStage);
public:
DeleteStage(OperationContext* txn,
const DeleteStageParams& params,
WorkingSet* ws,
Collection* collection,
PlanStage* child);
bool isEOF() final;
StageState doWork(WorkingSetID* out) final;
void doRestoreState() final;
StageType stageType() const final {
return STAGE_DELETE;
}
std::unique_ptr<PlanStageStats> getStats() final;
const SpecificStats* getSpecificStats() const final;
static const char* kStageType;
/**
* Extracts the number of documents deleted by the delete plan 'exec'.
*
* Should only be called if the root plan stage of 'exec' is DELETE and if 'exec' is EOF.
*/
static long long getNumDeleted(const PlanExecutor& exec);
private:
/**
* Stores 'idToRetry' in '_idRetrying' so the delete can be retried during the next call to
* work(). Always returns NEED_YIELD and sets 'out' to WorkingSet::INVALID_ID.
*/
StageState prepareToRetryWSM(WorkingSetID idToRetry, WorkingSetID* out);
DeleteStageParams _params;
// Not owned by us.
WorkingSet* _ws;
// Collection to operate on. Not owned by us. Can be NULL (if NULL, isEOF() will always
// return true). If non-NULL, the lifetime of the collection must supersede that of the
// stage.
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
DeleteStats _specificStats;
};
} // namespace mongo
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