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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 "mongo/bson/timestamp.h"
#include "mongo/db/query/record_id_bound.h"
#include "mongo/db/record_id.h"
namespace mongo {
struct CollectionScanParams {
enum Direction {
FORWARD = 1,
BACKWARD = -1,
};
enum class ScanBoundInclusion {
kExcludeBothStartAndEndRecords,
kIncludeStartRecordOnly,
kIncludeEndRecordOnly,
kIncludeBothStartAndEndRecords,
};
// If present, this parameter sets the start point of a forward scan or the end point of a
// reverse scan. A forward scan will start scanning at the document with the lowest RecordId
// greater than or equal to minRecord. A reverse scan will stop and return EOF on the first
// document with a RecordId less than minRecord, or a higher record if none exists. May only
// be used for scans on clustered collections and forward oplog scans. If exclusive
// bounds are required, a MatchExpression must be passed to the CollectionScan stage. This field
// cannot be used in conjunction with 'resumeAfterRecordId'
boost::optional<RecordIdBound> minRecord;
// If present, this parameter sets the start point of a reverse scan or the end point of a
// forward scan. A forward scan will stop and return EOF on the first document with a RecordId
// greater than maxRecord. A reverse scan will start scanning at the document with the
// highest RecordId less than or equal to maxRecord, or a lower record if none exists. May
// only be used for scans on clustered collections and forward oplog scans. If exclusive
// bounds are required, a MatchExpression must be passed to the CollectionScan stage. This field
// cannot be used in conjunction with 'resumeAfterRecordId'.
boost::optional<RecordIdBound> maxRecord;
// If true, the collection scan will return a token that can be used to resume the scan.
bool requestResumeToken = false;
// If present, the collection scan will seek to the exact RecordId, or return KeyNotFound if it
// does not exist. Must only be set on forward collection scans.
// This field cannot be used in conjunction with 'minRecord' or 'maxRecord'.
boost::optional<RecordId> resumeAfterRecordId;
Direction direction = FORWARD;
// By default, both start and end records will be included.
//
// For a FORWARD scan, the startRecord is the minRecord. For a BACKWARD scan, the startRecord is
// the maxRecord.
//
// Only compatible with bounded collection scans. Only excludes record bounds if the bound is
// also defined.
// Ex) A forward scan with [minRecord, maxRecord] of [boost::none, 10] and
// ScanBoundInclusion::kIncludeEndRecordOnly will yield the same results as
// ScanBoundInclusion::kIncludeBothStartAndEndRecords since the startRecord that would have been
// excluded is not defined anyway.
//
// Use with caution, as this can override a filter.
// Ex) Suppose we have [minRecord, maxRecord] of [-10, 10],
// ScanBoundInclusion::kIncludeEndRecordOnly, and a filter {$gte: RecordId(-10)} for a forward
// scan. The results would still exclude RecordId(-10) due to the ScanBoundInclusion.
ScanBoundInclusion boundInclusion = ScanBoundInclusion::kIncludeBothStartAndEndRecords;
// Do we want the scan to be 'tailable'? Only meaningful if the collection is capped.
bool tailable = false;
// Assert that the specified timestamp has not fallen off the oplog on a forward scan.
boost::optional<Timestamp> assertTsHasNotFallenOff = boost::none;
// Should we keep track of the timestamp of the latest oplog entry we've seen? This information
// is needed to merge cursors from the oplog in order of operation time when reading the oplog
// across a sharded cluster.
bool shouldTrackLatestOplogTimestamp = false;
// Once the first matching document is found, assume that all documents after it must match.
// This is useful for oplog queries where we know we will see records ordered by the ts field.
bool stopApplyingFilterAfterFirstMatch = false;
// Whether or not to wait for oplog visibility on oplog collection scans.
bool shouldWaitForOplogVisibility = false;
};
} // namespace mongo
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