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
|
/**
* 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.
*/
#include "mongo/db/exec/distinct_scan.h"
#include "mongo/db/concurrency/write_conflict_exception.h"
#include "mongo/db/exec/filter.h"
#include "mongo/db/exec/scoped_timer.h"
#include "mongo/db/exec/working_set_computed_data.h"
#include "mongo/db/index/index_access_method.h"
#include "mongo/db/index/index_descriptor.h"
namespace mongo {
using std::auto_ptr;
using std::vector;
// static
const char* DistinctScan::kStageType = "DISTINCT_SCAN";
DistinctScan::DistinctScan(OperationContext* txn, const DistinctParams& params, WorkingSet* workingSet)
: _txn(txn),
_workingSet(workingSet),
_descriptor(params.descriptor),
_iam(params.descriptor->getIndexCatalog()->getIndex(params.descriptor)),
_params(params),
_checker(&_params.bounds, _descriptor->keyPattern(), _params.direction),
_commonStats(kStageType) {
_specificStats.keyPattern = _params.descriptor->keyPattern();
_specificStats.indexName = _params.descriptor->indexName();
_specificStats.indexVersion = _params.descriptor->version();
// Set up our initial seek. If there is no valid data, just mark as EOF.
_commonStats.isEOF = !_checker.getStartSeekPoint(&_seekPoint);
}
PlanStage::StageState DistinctScan::work(WorkingSetID* out) {
++_commonStats.works;
if (_commonStats.isEOF) return PlanStage::IS_EOF;
// Adds the amount of time taken by work() to executionTimeMillis.
ScopedTimer timer(&_commonStats.executionTimeMillis);
boost::optional<IndexKeyEntry> kv;
try {
if (!_cursor) _cursor = _iam->newCursor(_txn, _params.direction == 1);
kv = _cursor->seek(_seekPoint);
}
catch (const WriteConflictException& wce) {
*out = WorkingSet::INVALID_ID;
return PlanStage::NEED_YIELD;
}
if (!kv) {
_commonStats.isEOF = true;
return PlanStage::IS_EOF;
}
++_specificStats.keysExamined;
switch (_checker.checkKey(kv->key, &_seekPoint)) {
case IndexBoundsChecker::MUST_ADVANCE:
// Try again next time. The checker has adjusted the _seekPoint.
++_commonStats.needTime;
return PlanStage::NEED_TIME;
case IndexBoundsChecker::DONE:
// There won't be a next time.
_commonStats.isEOF = true;
_cursor.reset();
return IS_EOF;
case IndexBoundsChecker::VALID:
// Return this key. Adjust the _seekPoint so that it is exclusive on the field we
// are using.
if (!kv->key.isOwned()) kv->key = kv->key.getOwned();
_seekPoint.keyPrefix = kv->key;
_seekPoint.prefixLen = _params.fieldNo + 1;
_seekPoint.prefixExclusive = true;
// Package up the result for the caller.
WorkingSetID id = _workingSet->allocate();
WorkingSetMember* member = _workingSet->get(id);
member->loc = kv->loc;
member->keyData.push_back(IndexKeyDatum(_descriptor->keyPattern(), kv->key, _iam));
member->state = WorkingSetMember::LOC_AND_IDX;
*out = id;
++_commonStats.advanced;
return PlanStage::ADVANCED;
}
invariant(false);
}
bool DistinctScan::isEOF() {
return _commonStats.isEOF;
}
void DistinctScan::saveState() {
_txn = NULL;
++_commonStats.yields;
// We always seek, so we don't care where the cursor is.
if (_cursor) _cursor->saveUnpositioned();
}
void DistinctScan::restoreState(OperationContext* opCtx) {
invariant(_txn == NULL);
_txn = opCtx;
++_commonStats.unyields;
if (_cursor) _cursor->restore(opCtx);
}
void DistinctScan::invalidate(OperationContext* txn, const RecordId& dl, InvalidationType type) {
++_commonStats.invalidates;
}
vector<PlanStage*> DistinctScan::getChildren() const {
vector<PlanStage*> empty;
return empty;
}
PlanStageStats* DistinctScan::getStats() {
auto_ptr<PlanStageStats> ret(new PlanStageStats(_commonStats, STAGE_DISTINCT_SCAN));
ret->specific.reset(new DistinctScanStats(_specificStats));
return ret.release();
}
const CommonStats* DistinctScan::getCommonStats() const {
return &_commonStats;
}
const SpecificStats* DistinctScan::getSpecificStats() const {
return &_specificStats;
}
} // namespace mongo
|
