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/**
* Copyright (C) 2018-present MongoDB, Inc.
*
* This program is free software: you can redistribute it and/or modify
* it under the terms of the Server Side Public License, version 1,
* as published by MongoDB, Inc.
*
* 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
* Server Side Public License for more details.
*
* You should have received a copy of the Server Side Public License
* along with this program. If not, see
* <http://www.mongodb.com/licensing/server-side-public-license>.
*
* 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 Server Side 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 <memory>
#include "mongo/db/exec/collection_scan_common.h"
#include "mongo/db/exec/requires_collection_stage.h"
#include "mongo/db/matcher/expression_leaf.h"
#include "mongo/db/record_id.h"
#include "mongo/s/resharding/resume_token_gen.h"
namespace mongo {
struct Record;
class SeekableRecordCursor;
class WorkingSet;
class OperationContext;
/**
* Scans over a collection, starting at the RecordId provided in params and continuing until
* there are no more records in the collection.
*
* Preconditions: Valid RecordId.
*/
class CollectionScan final : public RequiresCollectionStage {
public:
CollectionScan(ExpressionContext* expCtx,
const CollectionPtr& collection,
const CollectionScanParams& params,
WorkingSet* workingSet,
const MatchExpression* filter);
StageState doWork(WorkingSetID* out) final;
bool isEOF() final;
void doDetachFromOperationContext() final;
void doReattachToOperationContext() final;
StageType stageType() const final {
return STAGE_COLLSCAN;
}
Timestamp getLatestOplogTimestamp() const {
return _latestOplogEntryTimestamp;
}
BSONObj getPostBatchResumeToken() const {
// Return a resume token compatible with resumable initial sync.
if (_params.requestResumeToken) {
BSONObjBuilder builder;
_lastSeenId.serializeToken("$recordId", &builder);
return builder.obj();
}
// Return a resume token compatible with resharding oplog sync.
if (_params.shouldTrackLatestOplogTimestamp) {
return ResumeTokenOplogTimestamp{_latestOplogEntryTimestamp}.toBSON();
}
return {};
}
std::unique_ptr<PlanStageStats> getStats() final;
const SpecificStats* getSpecificStats() const final;
CollectionScanParams::Direction getDirection() const {
return _params.direction;
}
protected:
void doSaveStateRequiresCollection() final;
void doRestoreStateRequiresCollection() final;
private:
/**
* If the member (with id memberID) passes our filter, set *out to memberID and return that
* ADVANCED. Otherwise, free memberID and return NEED_TIME.
*/
StageState returnIfMatches(WorkingSetMember* member, WorkingSetID memberID, WorkingSetID* out);
/**
* Extracts the timestamp from the 'ts' field of 'record', and sets '_latestOplogEntryTimestamp'
* to that time if it isn't already greater. Throws an exception if the 'ts' field cannot be
* extracted.
*/
void setLatestOplogEntryTimestamp(const Record& record);
/**
* Asserts that the minimum timestamp in the query filter has not already fallen off the oplog.
*/
void assertTsHasNotFallenOffOplog(const Record& record);
// WorkingSet is not owned by us.
WorkingSet* _workingSet;
// The filter is not owned by us.
const MatchExpression* _filter;
std::unique_ptr<SeekableRecordCursor> _cursor;
CollectionScanParams _params;
RecordId _lastSeenId; // Null if nothing has been returned from _cursor yet.
// If _params.shouldTrackLatestOplogTimestamp is set and the collection is the oplog, the latest
// timestamp seen in the collection. Otherwise, this is a null timestamp.
Timestamp _latestOplogEntryTimestamp;
// Stats
CollectionScanStats _specificStats;
};
} // namespace mongo
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