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
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
|
/**
* 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/db/catalog/collection.h"
#include "mongo/db/exec/requires_collection_stage.h"
#include "mongo/db/exec/write_stage_common.h"
#include "mongo/db/ops/update_request.h"
#include "mongo/db/s/sharding_write_router.h"
#include "mongo/db/update/update_driver.h"
namespace mongo {
class OpDebug;
struct PlanSummaryStats;
struct UpdateStageParams {
using DocumentCounter = std::function<size_t(const BSONObj&)>;
UpdateStageParams(const UpdateRequest* r,
UpdateDriver* d,
OpDebug* o,
DocumentCounter&& documentCounter = nullptr)
: request(r),
driver(d),
opDebug(o),
canonicalQuery(nullptr),
numStatsForDoc(std::move(documentCounter)) {}
// Contains update parameters like whether it's a multi update or an upsert. Not owned.
// Must outlive the UpdateStage.
const UpdateRequest* request;
// Contains the logic for applying mods to documents. Not owned. Must outlive
// the UpdateStage.
UpdateDriver* driver;
// Needed to pass to Collection::updateDocument(...).
OpDebug* opDebug;
// Not owned here.
CanonicalQuery* canonicalQuery;
// Determines how the update stats should be incremented. Will be incremented by 1 if the
// function is empty.
DocumentCounter numStatsForDoc;
private:
// Default constructor not allowed.
UpdateStageParams();
};
/**
* Execution stage responsible for updates to documents. If the prior or newly-updated version of
* the document was requested to be returned, then ADVANCED is returned after updating a document.
* Otherwise, NEED_TIME is returned after updating a document if further updates are pending,
* and IS_EOF is returned if no documents were found or all updates have been performed.
*
* Callers of doWork() must be holding a write lock.
*/
class UpdateStage : public RequiresWritableCollectionStage {
UpdateStage(const UpdateStage&) = delete;
UpdateStage& operator=(const UpdateStage&) = delete;
public:
static constexpr StringData kStageType = "UPDATE"_sd;
UpdateStage(ExpressionContext* expCtx,
const UpdateStageParams& params,
WorkingSet* ws,
const ScopedCollectionAcquisition& collection,
PlanStage* child);
bool isEOF() override;
StageState doWork(WorkingSetID* out) override;
StageType stageType() const final {
return STAGE_UPDATE;
}
std::unique_ptr<PlanStageStats> getStats() final;
const SpecificStats* getSpecificStats() const final;
bool containsDotsAndDollarsField() const {
return _params.driver->containsDotsAndDollarsField();
}
protected:
UpdateStage(ExpressionContext* expCtx,
const UpdateStageParams& params,
WorkingSet* ws,
const ScopedCollectionAcquisition& collection);
void doSaveStateRequiresCollection() final {
_preWriteFilter.saveState();
}
void doRestoreStateRequiresCollection() final;
void _checkRestrictionsOnUpdatingShardKeyAreNotViolated(
const ScopedCollectionDescription& collDesc, const FieldRefSet& shardKeyPaths);
UpdateStageParams _params;
// Not owned by us.
WorkingSet* _ws;
// Stats
UpdateStats _specificStats;
// A user-initiated write is one which is not caused by oplog application and is not part of a
// chunk migration
bool _isUserInitiatedWrite;
// These get reused for each update.
mutablebson::Document& _doc;
mutablebson::DamageVector _damages;
private:
/**
* Computes the result of applying mods to the document 'oldObj' at RecordId 'recordId' in
* memory, then commits these changes to the database. Returns a possibly unowned copy
* of the newly-updated version of the document.
*/
BSONObj transformAndUpdate(const Snapshotted<BSONObj>& oldObj,
RecordId& recordId,
bool writeOnOrphan);
/**
* Stores 'idToRetry' in '_idRetrying' so the update can be retried during the next call to
* doWork(). Sets 'out' to WorkingSet::INVALID_ID.
*/
void prepareToRetryWSM(WorkingSetID idToRetry, WorkingSetID* out);
/**
* Performs checks on whether the existing or new shard key fields would change the owning
* shard, including whether the owning shard under the current key pattern would change as a
* result of the update, or if the destined recipient under the new shard key pattern from
* resharding would change as a result of the update.
*
* Throws if the updated document does not have all of the shard key fields or no longer belongs
* to this shard.
*
* Accepting a 'newObjCopy' parameter is a performance enhancement for updates which weren't
* performed in-place to avoid rendering a full copy of the updated document multiple times.
*/
void checkUpdateChangesShardKeyFields(const boost::optional<BSONObj>& newObjCopy,
const Snapshotted<BSONObj>& oldObj);
/**
* Checks that the updated doc has all required shard key fields and throws if it does not.
*
* Also checks if the updated doc still belongs to this node and throws if it does not. If the
* doc no longer belongs to this shard, this means that one or more shard key field values have
* been updated to a value belonging to a chunk that is not owned by this shard. We cannot apply
* this update atomically.
*/
void checkUpdateChangesExistingShardKey(const BSONObj& newObj,
const Snapshotted<BSONObj>& oldObj);
void checkUpdateChangesReshardingKey(const ShardingWriteRouter& shardingWriteRouter,
const BSONObj& newObj,
const Snapshotted<BSONObj>& oldObj);
// If not WorkingSet::INVALID_ID, we use this rather than asking our child what to do next.
WorkingSetID _idRetrying;
// If not WorkingSet::INVALID_ID, we return this member to our caller.
WorkingSetID _idReturning;
// Guard against the "Halloween Problem": If we're scanning an index {x:1} and performing
// {$inc:{x:5}}, we'll keep moving the document forward and it will continue to reappear in our
// index scan. Unless the index is multikey, the underlying query machinery won't de-dup so we
// keep track of already updated docs in '_updatedRecordIds'.
typedef stdx::unordered_set<RecordId, RecordId::Hasher> RecordIdSet;
const std::unique_ptr<RecordIdSet> _updatedRecordIds;
/**
* This member is used to check whether the write should be performed, and if so, any other
* behavior that should be done as part of the write (e.g. skipping it because it affects an
* orphan document). A yield cannot happen between the check and the write, so the checks are
* embedded in the stage.
*
* It's refreshed after yielding and reacquiring the locks.
*/
write_stage_common::PreWriteFilter _preWriteFilter;
};
} // namespace mongo
|
