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
|
/**
* 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 <cstdint>
#include <memory>
#include "mongo/db/storage/record_store.h"
#include "mongo/db/storage/sorted_data_interface.h"
#include "mongo/util/fail_point.h"
namespace mongo {
class DataThrottle;
class IndexAccessMethod;
class OperationContext;
class SortedDataInterface;
/**
* Cursor wrapper class that creates a cursor internally and throttles record fetching according to
* the DataThrottle instance passed into its constructor.
*/
class SeekableRecordThrottleCursor {
public:
SeekableRecordThrottleCursor(OperationContext* opCtx,
const RecordStore* rs,
DataThrottle* dataThrottle);
boost::optional<Record> seekExact(OperationContext* opCtx, const RecordId& id);
boost::optional<Record> next(OperationContext* opCtx);
void save() {
_cursor->save();
}
bool restore() {
return _cursor->restore();
}
private:
std::unique_ptr<SeekableRecordCursor> _cursor;
DataThrottle* _dataThrottle;
};
/**
* Cursor wrapper class that creates a cursor internally and throttles record fetching according to
* the DataThrottle instance passed into its constructor.
*/
class SortedDataInterfaceThrottleCursor {
public:
SortedDataInterfaceThrottleCursor(OperationContext* opCtx,
const IndexAccessMethod* iam,
DataThrottle* dataThrottle);
boost::optional<IndexKeyEntry> seek(OperationContext* opCtx, const KeyString::Value& key);
boost::optional<KeyStringEntry> seekForKeyString(OperationContext* opCtx,
const KeyString::Value& key);
boost::optional<IndexKeyEntry> next(OperationContext* opCtx);
boost::optional<KeyStringEntry> nextKeyString(OperationContext* opCtx);
void save() {
_cursor->save();
}
void restore() {
_cursor->restore();
}
private:
std::unique_ptr<SortedDataInterface::Cursor> _cursor;
DataThrottle* _dataThrottle;
};
/**
* Throttles the amount of data processed within a unit of time. Puts the thread to sleep via an
* opCtx -- so it is interruptible -- whenever the data limit set by the 'maxValidateMBperSec'
* server parameter is exceeded before the time unit is done.
*/
class DataThrottle {
public:
DataThrottle(OperationContext* opCtx)
: _startMillis(
opCtx->getServiceContext()->getFastClockSource()->now().toMillisSinceEpoch()),
_bytesProcessed(0),
_totalElapsedTimeSec(0),
_totalMBProcessed(0),
_shouldNotThrottle(false) {}
/**
* If throttling is not enabled by calling turnThrottlingOff(), or if
* 'maxValidateMBperSec' == 0, then this is a no-op.
*
* When the accumulated number of bytes processed in each second reaches or exceeds the limit
* set by the 'maxValidateMBperSec' server parameter, the throttle mechanism gets engaged to
* wait for the remainder of that second by putting the thread to sleep.
*
* In addition to throttling, while the thread is waiting, its operation context remains
* interruptible.
*/
void awaitIfNeeded(OperationContext* opCtx, const int64_t dataSize);
void turnThrottlingOff() {
_shouldNotThrottle = true;
}
private:
// Point-in-time (milliseconds) when tracking for the current second has started.
int64_t _startMillis;
// Number of bytes processed in the current second being tracked by '_startMillis'. This will
// contain the number of bytes processed between '_startMillis' and '_startMillis + 999'.
uint64_t _bytesProcessed;
float _totalElapsedTimeSec;
float _totalMBProcessed;
// Whether the throttle should be active.
bool _shouldNotThrottle;
};
} // namespace mongo
|
