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
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
|
/**
* Copyright (C) 2019-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 <boost/optional.hpp>
#include "mongo/db/pipeline/document_source.h"
#include "mongo/db/pipeline/lite_parsed_document_source.h"
#include "mongo/db/pipeline/lite_parsed_pipeline.h"
#include "mongo/db/pipeline/stage_constraints.h"
namespace mongo {
class DocumentSourceUnionWith final : public DocumentSource {
public:
static constexpr StringData kStageName = "$unionWith"_sd;
static boost::intrusive_ptr<DocumentSource> createFromBson(
BSONElement elem, const boost::intrusive_ptr<ExpressionContext>& expCtx);
class LiteParsed final : public LiteParsedDocumentSourceNestedPipelines {
public:
static std::unique_ptr<LiteParsed> parse(const NamespaceString& nss,
const BSONElement& spec);
LiteParsed(std::string parseTimeName,
NamespaceString foreignNss,
boost::optional<LiteParsedPipeline> pipeline)
: LiteParsedDocumentSourceNestedPipelines(
std::move(parseTimeName), std::move(foreignNss), std::move(pipeline)) {}
PrivilegeVector requiredPrivileges(bool isMongos,
bool bypassDocumentValidation) const override final;
};
DocumentSourceUnionWith(const boost::intrusive_ptr<ExpressionContext>& expCtx,
std::unique_ptr<Pipeline, PipelineDeleter> pipeline)
: DocumentSource(kStageName, expCtx), _pipeline(std::move(pipeline)) {
// If this pipeline is being run as part of explain, then cache a copy to use later during
// serialization.
if (expCtx->explain >= ExplainOptions::Verbosity::kExecStats) {
_cachedPipeline = _pipeline->getSources();
}
}
DocumentSourceUnionWith(const DocumentSourceUnionWith& original,
const boost::intrusive_ptr<ExpressionContext>& newExpCtx)
: DocumentSource(kStageName,
newExpCtx ? newExpCtx : original.pExpCtx->copyWith(original.pExpCtx->ns)),
_pipeline(original._pipeline->clone()) {}
~DocumentSourceUnionWith();
const char* getSourceName() const final {
return kStageName.rawData();
}
GetModPathsReturn getModifiedPaths() const final {
// Since we might have a document arrive from the foreign pipeline with the same path as a
// document in the main pipeline. Without introspecting the sub-pipeline, we must report
// that all paths have been modified.
return {GetModPathsReturn::Type::kAllPaths, {}, {}};
}
StageConstraints constraints(Pipeline::SplitState) const final {
StageConstraints unionConstraints(
StreamType::kStreaming,
PositionRequirement::kNone,
HostTypeRequirement::kAnyShard,
DiskUseRequirement::kNoDiskUse,
FacetRequirement::kAllowed,
TransactionRequirement::kNotAllowed,
// The check to disallow $unionWith on a sharded collection within $lookup happens
// outside of the constraints as long as the involved namespaces are reported correctly.
LookupRequirement::kAllowed,
UnionRequirement::kAllowed);
if (_pipeline) {
// The constraints of the sub-pipeline determine the constraints of the $unionWith
// stage. We want to forward the strictest requirements of the stages in the
// sub-pipeline.
unionConstraints = StageConstraints::getStrictestConstraints(_pipeline->getSources(),
unionConstraints);
}
// DocumentSourceUnionWith cannot directly swap with match but it contains custom logic in
// the doOptimizeAt() member function to allow itself to duplicate any match ahead in the
// current pipeline and place one copy inside its sub-pipeline and one copy behind in the
// current pipeline.
unionConstraints.canSwapWithMatch = false;
return unionConstraints;
}
DepsTracker::State getDependencies(DepsTracker* deps) const final;
void addVariableRefs(std::set<Variables::Id>* refs) const final;
boost::optional<DistributedPlanLogic> distributedPlanLogic() final {
// {shardsStage, mergingStage, sortPattern}
return DistributedPlanLogic{nullptr, this, boost::none};
}
void addInvolvedCollections(stdx::unordered_set<NamespaceString>* collectionNames) const final;
void detachFromOperationContext() final;
void reattachToOperationContext(OperationContext* opCtx) final;
bool usedDisk() final;
const SpecificStats* getSpecificStats() const final {
return &_stats;
}
const Pipeline& getPipeline() const {
return *_pipeline;
}
boost::intrusive_ptr<DocumentSource> clone(
const boost::intrusive_ptr<ExpressionContext>& newExpCtx) const final;
const Pipeline::SourceContainer* getSubPipeline() const final {
if (_pipeline) {
return &_pipeline->getSources();
}
return nullptr;
}
protected:
GetNextResult doGetNext() final;
Pipeline::SourceContainer::iterator doOptimizeAt(Pipeline::SourceContainer::iterator itr,
Pipeline::SourceContainer* container) final;
boost::intrusive_ptr<DocumentSource> optimize() final {
_pipeline->optimizePipeline();
return this;
}
void doDispose() final;
private:
enum ExecutionProgress {
// We haven't yet iterated 'pSource' to completion.
kIteratingSource,
// We finished iterating 'pSource', but haven't started on the sub pipeline and need to do
// some setup first.
kStartingSubPipeline,
// We finished iterating 'pSource' and are now iterating '_pipeline', but haven't finished
// yet.
kIteratingSubPipeline,
// There are no more results.
kFinished
};
Value serialize(boost::optional<ExplainOptions::Verbosity> explain = boost::none) const final;
void addViewDefinition(NamespaceString nss, std::vector<BSONObj> viewPipeline);
void logStartingSubPipeline(const std::vector<BSONObj>& serializedPipeline);
void logShardedViewFound(
const ExceptionFor<ErrorCodes::CommandOnShardedViewNotSupportedOnMongod>& e);
std::unique_ptr<Pipeline, PipelineDeleter> _pipeline;
Pipeline::SourceContainer _cachedPipeline;
ExecutionProgress _executionState = ExecutionProgress::kIteratingSource;
UnionWithStats _stats;
};
} // namespace mongo
|
