1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
|
/**
* Copyright (C) 2011 10gen 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 "cursor.h"
namespace mongo {
class CandidatePlanCharacter;
class ExplainQueryInfo;
class FieldRangeSet;
/**
* Adds functionality to Cursor for running multiple plans, running out of order plans,
* utilizing covered indexes, and generating explain output.
*/
class QueryOptimizerCursor : public Cursor {
public:
/** Candidate plans for the query before it begins running. */
virtual CandidatePlanCharacter initialCandidatePlans() const = 0;
/** FieldRangeSet for the query before it begins running. */
virtual const FieldRangeSet *initialFieldRangeSet() const = 0;
/** @return true if the plan for the current iterate is out of order. */
virtual bool currentPlanScanAndOrderRequired() const = 0;
/** @return true when there may be multiple plans running and some are in order. */
virtual bool runningInitialInOrderPlan() const = 0;
/**
* @return true when some query plans may have been excluded due to plan caching, for a
* non-$or query.
*/
virtual bool hasPossiblyExcludedPlans() const = 0;
/**
* @return true when both in order and out of order candidate plans were available, and
* an out of order candidate plan completed iteration.
*/
virtual bool completePlanOfHybridSetScanAndOrderRequired() const = 0;
/** Clear recorded indexes for the current clause's query patterns. */
virtual void clearIndexesForPatterns() = 0;
/** Stop returning results from out of order plans and do not allow them to complete. */
virtual void abortOutOfOrderPlans() = 0;
/** Note match information for the current iterate, to generate explain output. */
virtual void noteIterate( bool match, bool loadedDocument, bool chunkSkip ) = 0;
/** Note a lock yield for explain output reporting. */
virtual void noteYield() = 0;
/** @return explain output for the query run by this cursor. */
virtual shared_ptr<ExplainQueryInfo> explainQueryInfo() const = 0;
};
} // namespace mongo
|
