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
218
219
220
|
// @file balancer_policy.h
/**
* Copyright (C) 2010 10gen 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.
*/
#ifndef S_BALANCER_POLICY_HEADER
#define S_BALANCER_POLICY_HEADER
#include "mongo/db/jsobj.h"
#include "mongo/s/type_chunk.h"
namespace mongo {
struct ChunkInfo {
const BSONObj min;
const BSONObj max;
ChunkInfo( const BSONObj& a_min, const BSONObj& a_max )
: min( a_min.getOwned() ), max( a_max.getOwned() ){}
ChunkInfo( const BSONObj& chunk )
: min(chunk[ChunkType::min()].Obj().getOwned()),
max(chunk[ChunkType::max()].Obj().getOwned()) {
}
std::string toString() const;
};
struct TagRange {
BSONObj min;
BSONObj max;
std::string tag;
TagRange(){}
TagRange( const BSONObj& a_min, const BSONObj& a_max, const std::string& a_tag )
: min( a_min.getOwned() ), max( a_max.getOwned() ), tag( a_tag ){}
std::string toString() const;
};
class ShardInfo {
public:
ShardInfo();
ShardInfo( long long maxSize, long long currSize,
bool draining, bool opsQueued,
const std::set<std::string>& tags = std::set<std::string>(),
const std::string& _mongoVersion = std::string("") );
void addTag( const std::string& tag );
/** @return true if we have the tag OR if the tag is "" */
bool hasTag( const std::string& tag ) const;
/**
* @return true if a shard cannot receive any new chunks because it reaches 'shardLimits'.
* Expects the optional fields "maxSize", can in size in MB, and "usedSize", currently used size
* in MB, on 'shardLimits'.
*/
bool isSizeMaxed() const;
/**
* @return true if 'shardLimist' contains a field "draining". Expects the optional field
* "isDraining" on 'shrdLimits'.
*/
bool isDraining() const { return _draining; }
/**
* @return true if a shard currently has operations in any of its writeback queues
*/
bool hasOpsQueued() const { return _hasOpsQueued; }
long long getMaxSize() const { return _maxSize; }
long long getCurrSize() const { return _currSize; }
std::string getMongoVersion() const { return _mongoVersion; }
std::string toString() const;
private:
long long _maxSize;
long long _currSize;
bool _draining;
bool _hasOpsQueued;
std::set<std::string> _tags;
std::string _mongoVersion;
};
struct MigrateInfo {
const std::string ns;
const std::string to;
const std::string from;
const ChunkInfo chunk;
MigrateInfo( const std::string& a_ns , const std::string& a_to , const std::string& a_from , const BSONObj& a_chunk )
: ns( a_ns ) , to( a_to ) , from( a_from ), chunk( a_chunk ) {}
};
typedef std::map< std::string,ShardInfo > ShardInfoMap;
typedef std::map< std::string,std::vector<BSONObj> > ShardToChunksMap;
class DistributionStatus : boost::noncopyable {
public:
DistributionStatus( const ShardInfoMap& shardInfo,
const ShardToChunksMap& shardToChunksMap );
// only used when building
/**
* @return if range is valid
*/
bool addTagRange( const TagRange& range );
// ---- these methods might be better suiting in BalancerPolicy
/**
* @param forTag "" if you don't care, or a tag
* @return shard best suited to receive a chunk
*/
std::string getBestReceieverShard( const std::string& forTag ) const;
/**
* @return the shard with the most chunks
* based on # of chunks with the given tag
*/
std::string getMostOverloadedShard( const std::string& forTag ) const;
// ---- basic accessors, counters, etc...
/** @return total number of chunks */
unsigned totalChunks() const;
/** @return number of chunks in this shard */
unsigned numberOfChunksInShard( const std::string& shard ) const;
/** @return number of chunks in this shard with the given tag */
unsigned numberOfChunksInShardWithTag( const std::string& shard, const std::string& tag ) const;
/** @return chunks for the shard */
const std::vector<BSONObj>& getChunks( const std::string& shard ) const;
/** @return all tags we know about, not include "" */
const std::set<std::string>& tags() const { return _allTags; }
/** @return the right tag for chunk, possibly "" */
std::string getTagForChunk( const BSONObj& chunk ) const;
/** @return all shards we know about */
const std::set<std::string>& shards() const { return _shards; }
/** @return the ShardInfo for the shard */
const ShardInfo& shardInfo( const std::string& shard ) const;
/** writes all state to log() */
void dump() const;
private:
const ShardInfoMap& _shardInfo;
const ShardToChunksMap& _shardChunks;
std::map<BSONObj,TagRange> _tagRanges;
std::set<std::string> _allTags;
std::set<std::string> _shards;
};
class BalancerPolicy {
public:
/**
* Returns a suggested chunk to move whithin a collection's shards, given information about
* space usage and number of chunks for that collection. If the policy doesn't recommend
* moving, it returns NULL.
*
* @param ns is the collections namepace.
* @param DistributionStatus holds all the info about the current state of the cluster/namespace
* @param balancedLastTime is the number of chunks effectively moved in the last round.
* @returns NULL or MigrateInfo of the best move to make towards balacing the collection.
* caller owns the MigrateInfo instance
*/
static MigrateInfo* balance( const std::string& ns,
const DistributionStatus& distribution,
int balancedLastTime );
private:
static bool _isJumbo( const BSONObj& chunk );
};
} // namespace mongo
#endif // S_BALANCER_POLICY_HEADER
|
