summaryrefslogtreecommitdiff
path: root/src/mongo/db/exec/update.h
blob: 7010c4ceb98ab7bfe67084675210ebf12b1eccbb (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
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
/**
 *    Copyright (C) 2014 MongoDB 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 <boost/scoped_ptr.hpp>

#include "mongo/db/catalog/collection.h"
#include "mongo/db/exec/plan_stage.h"
#include "mongo/db/jsobj.h"
#include "mongo/db/ops/update_driver.h"
#include "mongo/db/ops/update_request.h"
#include "mongo/db/ops/update_result.h"

namespace mongo {

class OperationContext;

struct UpdateStageParams {
    UpdateStageParams(const UpdateRequest* r, UpdateDriver* d, OpDebug* o)
        : request(r), driver(d), opDebug(o), canonicalQuery(NULL) {}

    // 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;

private:
    // Default constructor not allowed.
    UpdateStageParams();
};

/**
 * Execution stage responsible for updates to documents and upserts. NEED_TIME is returned
 * after performing an update or an insert.
 *
 * Callers of work() must be holding a write lock.
 */
class UpdateStage : public PlanStage {
    MONGO_DISALLOW_COPYING(UpdateStage);

public:
    UpdateStage(OperationContext* txn,
                const UpdateStageParams& params,
                WorkingSet* ws,
                Collection* collection,
                PlanStage* child);

    virtual bool isEOF();
    virtual StageState work(WorkingSetID* out);

    virtual void saveState();
    virtual void restoreState(OperationContext* opCtx);
    virtual void invalidate(OperationContext* txn, const RecordId& dl, InvalidationType type);

    virtual std::vector<PlanStage*> getChildren() const;

    virtual StageType stageType() const {
        return STAGE_UPDATE;
    }

    virtual PlanStageStats* getStats();

    virtual const CommonStats* getCommonStats();

    virtual const SpecificStats* getSpecificStats();

    static const char* kStageType;

    /**
     * Converts the execution stats (stored by the update stage as an UpdateStats) for the
     * update plan represented by 'exec' into the UpdateResult format used to report the results
     * of writes.
     *
     * Also responsible for filling out 'opDebug' with execution info.
     *
     * Should only be called once this stage is EOF.
     */
    static UpdateResult makeUpdateResult(PlanExecutor* exec, OpDebug* opDebug);

    /**
     * Computes the document to insert if the upsert flag is set to true and no matching
     * documents are found in the database. The document to upsert is computing using the
     * query 'cq' and the update mods contained in 'driver'.
     *
     * If 'cq' is NULL, which can happen for the idhack update fast path, then 'query' is
     * used to compute the doc to insert instead of 'cq'.
     *
     * 'doc' is the mutable BSON document which you would like the update driver to use
     * when computing the document to insert.
     *
     * Set 'isInternalRequest' to true if the upsert was issued by the replication or
     * sharding systems.
     *
     * Fills out whether or not this is a fastmodinsert in 'stats'.
     *
     * Returns the document to insert in *out.
     */
    static Status applyUpdateOpsForInsert(const CanonicalQuery* cq,
                                          const BSONObj& query,
                                          UpdateDriver* driver,
                                          UpdateLifecycle* lifecycle,
                                          mutablebson::Document* doc,
                                          bool isInternalRequest,
                                          UpdateStats* stats,
                                          BSONObj* out);

private:
    /**
     * Computes the result of applying mods to the document 'oldObj' at RecordId 'loc' in
     * memory, then commits these changes to the database.
     */
    void transformAndUpdate(const Snapshotted<BSONObj>& oldObj, RecordId& loc);

    /**
     * Computes the document to insert and inserts it into the collection. Used if the
     * user requested an upsert and no matching documents were found.
     */
    void doInsert();

    /**
     * Have we performed all necessary updates? Even if this is true, we might not be EOF,
     * as we might still have to do an insert.
     */
    bool doneUpdating();

    /**
     * Examines the stats / update request and returns whether there is still an insert left
     * to do. If so then this stage is not EOF yet.
     */
    bool needInsert();

    /**
     * Helper for restoring the state of this update.
     */
    Status restoreUpdateState(OperationContext* opCtx);

    // Transactional context.  Not owned by us.
    OperationContext* _txn;

    UpdateStageParams _params;

    // Not owned by us.
    WorkingSet* _ws;

    // Not owned by us. May be NULL.
    Collection* _collection;

    // Owned by us.
    boost::scoped_ptr<PlanStage> _child;

    // Stats
    CommonStats _commonStats;
    UpdateStats _specificStats;

    // If the update was in-place, we may see it again.  This only matters if we're doing
    // a multi-update; if we're not doing a multi-update we stop after one update and we
    // won't see any more docs.
    //
    // For example: 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.
    //
    // If the update wasn't in-place we may see it again.  Our query may return the new
    // document and we wouldn't want to update that.
    //
    // So, no matter what, we keep track of where the doc wound up.
    typedef unordered_set<RecordId, RecordId::Hasher> DiskLocSet;
    const boost::scoped_ptr<DiskLocSet> _updatedLocs;

    // These get reused for each update.
    mutablebson::Document& _doc;
    mutablebson::DamageVector _damages;
};

}  // namespace mongo