blob: b76681229714fae335ffb227f5c564c90982d63f (
plain)
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
82
83
84
85
86
87
88
|
/**
* Copyright (C) 2013 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.
*/
#include "mongo/db/matcher/expression.h"
#pragma once
namespace mongo {
/**
* Logic for how indices can be used with an expression.
*/
class Indexability {
public:
/**
* Is an index over me->path() useful?
* This is the same thing as being sargable, if you have a RDBMS background.
*/
static bool nodeCanUseIndexOnOwnField(const MatchExpression* me) {
if (me->path().empty()) {
return false;
}
if (arrayUsesIndexOnOwnField(me)) {
return true;
}
return me->matchType() == MatchExpression::LTE
|| me->matchType() == MatchExpression::LT
|| me->matchType() == MatchExpression::EQ
|| me->matchType() == MatchExpression::GT
|| me->matchType() == MatchExpression::GTE
|| me->matchType() == MatchExpression::REGEX
|| me->matchType() == MatchExpression::MOD
|| me->matchType() == MatchExpression::MATCH_IN
|| me->matchType() == MatchExpression::TYPE_OPERATOR
|| me->matchType() == MatchExpression::GEO
|| me->matchType() == MatchExpression::GEO_NEAR
|| me->matchType() == MatchExpression::TEXT;
}
/**
* This array operator doesn't have any children with fields and can use an index.
*
* Example: a: {$elemMatch: {$gte: 1, $lte: 1}}.
*/
static bool arrayUsesIndexOnOwnField(const MatchExpression* me) {
return me->isArray() && MatchExpression::ELEM_MATCH_VALUE == me->matchType();
}
/**
* Certain array operators require that the field for that operator is prepended
* to all fields in that operator's children.
*
* Example: a: {$elemMatch: {b:1, c:1}}.
*/
static bool arrayUsesIndexOnChildren(const MatchExpression* me) {
return me->isArray() && (MatchExpression::ELEM_MATCH_OBJECT == me->matchType()
|| MatchExpression::ALL == me->matchType());
};
};
} // namespace mongo
|
