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
|
/**
* Copyright (C) 2008-2015 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 <string>
#include "mongo/bson/bsonmisc.h"
#include "mongo/bson/bsonobj.h"
#include "mongo/s/client/shard.h"
namespace mongo {
class ChunkType;
struct ChunkVersion;
class OperationContext;
class ConfigDiffTrackerBase {
public:
/**
* Structure repsenting the generated query and sort order for a chunk diffing operation.
*/
struct QueryAndSort {
QueryAndSort(BSONObj inQuery, BSONObj inSort) : query(inQuery), sort(inSort) {}
std::string toString() const;
const BSONObj query;
const BSONObj sort;
};
};
/**
* This class manages and applies diffs from partial config server data reloads. Because the config
* data can be large, we want to update it in small parts, not all-at-once. Once a
* ConfigDiffTracker is created, the current config data is *attached* to it, and it is then able
* to modify the data.
*
* The current form is templated b/c the overall algorithm is identical between mongos and mongod,
* but the actual chunk maps used differ in implementation. We don't want to copy the
* implementation, because the logic is identical, or the chunk data, because that would be slow
* for big clusters, so this is the alternative for now.
*
* TODO: Standardize between mongos and mongod and convert template parameters to types.
*/
template <class ValType>
class ConfigDiffTracker : public ConfigDiffTrackerBase {
public:
// Stores ranges indexed by max or min key
typedef typename std::map<BSONObj, ValType, BSONObjCmp> RangeMap;
// Pair of iterators defining a subset of ranges
typedef typename std::pair<typename RangeMap::iterator, typename RangeMap::iterator>
RangeOverlap;
// Map of shard identifiers to the maximum chunk version on that shard
typedef typename std::map<ShardId, ChunkVersion> MaxChunkVersionMap;
ConfigDiffTracker();
virtual ~ConfigDiffTracker();
/**
* The tracker attaches to a set of ranges with versions, and uses a config server
* connection to update these. Because the set of ranges and versions may be large, they
* aren't owned by the tracker, they're just passed in and updated. Therefore they must all
* stay in scope while the tracker is working.
*
* TODO: Make a standard VersionedRange to encapsulate this info in both mongod and mongos?
*/
void attach(const std::string& ns,
RangeMap& currMap,
ChunkVersion& maxVersion,
MaxChunkVersionMap& maxShardVersions);
// Call after load for more information
int numValidDiffs() const {
return _validDiffs;
}
// Applies changes to the config data from a vector of chunks passed in. Also includes minor
// version changes for particular major-version chunks if explicitly specified.
// Returns the number of diffs processed, or -1 if the diffs were inconsistent.
int calculateConfigDiff(OperationContext* txn, const std::vector<ChunkType>& chunks);
// Returns the query needed to find new changes to a collection from the config server
// Needed only if a custom connection is required to the config server
QueryAndSort configDiffQuery() const;
protected:
/**
* Determines which chunks are actually being remembered by our RangeMap. Allows individual
* shards to filter out results, which belong to the local shard only.
*/
virtual bool isTracked(const ChunkType& chunk) const = 0;
/**
* Whether or not our RangeMap uses min or max keys
*/
virtual bool isMinKeyIndexed() const {
return true;
}
virtual std::pair<BSONObj, ValType> rangeFor(OperationContext* txn,
const ChunkType& chunk) const = 0;
virtual ShardId shardFor(OperationContext* txn, const std::string& name) const = 0;
private:
void _assertAttached() const;
// Whether or not a range exists in the min/max region
bool _isOverlapping(const BSONObj& min, const BSONObj& max);
// Returns a subset of ranges overlapping the region min/max
RangeOverlap _overlappingRange(const BSONObj& min, const BSONObj& max);
std::string _ns;
RangeMap* _currMap;
ChunkVersion* _maxVersion;
MaxChunkVersionMap* _maxShardVersions;
// Store for later use
int _validDiffs;
};
} // namespace mongo
|
