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
|
/**
* Copyright (C) 2022-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.
*/
#include "mongo/db/pipeline/sort_reorder_helpers.h"
namespace mongo {
bool checkModifiedPathsSortReorder(const SortPattern& sortPattern,
const DocumentSource::GetModPathsReturn& modPaths) {
for (const auto& sortKey : sortPattern) {
if (!sortKey.fieldPath.has_value()) {
return false;
}
if (sortKey.fieldPath->getPathLength() < 1) {
return false;
}
auto sortField = sortKey.fieldPath->getFieldName(0);
auto it = std::find_if(
modPaths.paths.begin(), modPaths.paths.end(), [&sortField](const auto& modPath) {
// Finds if the shorter path is a prefix field of or the same as the longer one.
return sortField == modPath || expression::isPathPrefixOf(sortField, modPath) ||
expression::isPathPrefixOf(modPath, sortField);
});
if (it != modPaths.paths.end()) {
return false;
}
}
return true;
}
Pipeline::SourceContainer::iterator tryReorderingWithSort(Pipeline::SourceContainer::iterator itr,
Pipeline::SourceContainer* container) {
auto docSource = itr->get();
invariant(dynamic_cast<DocumentSourceLookUp*>(docSource) ||
dynamic_cast<DocumentSourceGraphLookUp*>(docSource));
// If we have $graphLookup or $lookup followed by $sort, and $sort does not use any fields
// created by it, they can swap.
// TODO (SERVER-55417): Conditionally reorder $sort and $lookup depending on whether the
// query planner allows for an index-provided sort.
auto nextSort = dynamic_cast<DocumentSourceSort*>(std::next(itr)->get());
if (nextSort &&
checkModifiedPathsSortReorder(nextSort->getSortKeyPattern(),
docSource->getModifiedPaths())) {
std::swap(*itr, *std::next(itr));
return itr == container->begin() ? itr : std::prev(itr);
}
return itr;
}
} // namespace mongo
|
