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
|
/**
* Copyright (C) 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.
*/
#define MONGO_LOG_DEFAULT_COMPONENT ::mongo::logger::LogComponent::kSharding
#include "mongo/platform/basic.h"
#include "mongo/s/chunk_diff.h"
#include "mongo/db/namespace_string.h"
#include "mongo/db/s/collection_metadata.h"
#include "mongo/s/catalog/type_chunk.h"
#include "mongo/s/chunk_version.h"
#include "mongo/util/log.h"
#include "mongo/util/mongoutils/str.h"
namespace mongo {
template <class ValType>
ConfigDiffTracker<ValType>::ConfigDiffTracker(const std::string& ns,
RangeMap* currMap,
ChunkVersion* maxVersion,
MaxChunkVersionMap* maxShardVersions)
: _ns(ns), _currMap(currMap), _maxVersion(maxVersion), _maxShardVersions(maxShardVersions) {
invariant(_currMap);
invariant(_maxVersion);
invariant(_maxShardVersions);
}
template <class ValType>
ConfigDiffTracker<ValType>::~ConfigDiffTracker() = default;
template <class ValType>
bool ConfigDiffTracker<ValType>::_isOverlapping(const BSONObj& min, const BSONObj& max) {
RangeOverlap overlap = _overlappingRange(min, max);
return overlap.first != overlap.second;
}
template <class ValType>
typename ConfigDiffTracker<ValType>::RangeOverlap ConfigDiffTracker<ValType>::_overlappingRange(
const BSONObj& min, const BSONObj& max) {
typename RangeMap::iterator low;
typename RangeMap::iterator high;
if (isMinKeyIndexed()) {
// Returns the first chunk with a min key that is >= min - implies the
// previous chunk cannot overlap min
low = _currMap->lower_bound(min);
// Returns the first chunk with a min key that is >= max - implies the
// chunk does not overlap max
high = _currMap->lower_bound(max);
} else {
// Returns the first chunk with a max key that is > min - implies that
// the chunk overlaps min
low = _currMap->upper_bound(min);
// Returns the first chunk with a max key that is > max - implies that
// the next chunk cannot not overlap max
high = _currMap->upper_bound(max);
}
return RangeOverlap(low, high);
}
template <class ValType>
int ConfigDiffTracker<ValType>::calculateConfigDiff(OperationContext* txn,
const std::vector<ChunkType>& chunks) {
// Apply the chunk changes to the ranges and versions
//
// Overall idea here is to work in two steps :
// 1. For all the new chunks we find, increment the maximum version per-shard and
// per-collection, and remove any conflicting chunks from the ranges.
// 2. For all the new chunks we're interested in (all of them for mongos, just chunks on
// the shard for mongod) add them to the ranges.
std::vector<ChunkType> newTracked;
// Store epoch now so it doesn't change when we change max
OID currEpoch = _maxVersion->epoch();
_validDiffs = 0;
for (const ChunkType& chunk : chunks) {
const ChunkVersion& chunkVersion = chunk.getVersion();
if (!chunkVersion.hasEqualEpoch(currEpoch)) {
warning() << "got invalid chunk version " << chunkVersion << " in document "
<< redact(chunk.toString())
<< " when trying to load differing chunks at version "
<< ChunkVersion(
_maxVersion->majorVersion(), _maxVersion->minorVersion(), currEpoch);
// Don't keep loading, since we know we'll be broken here
return -1;
}
_validDiffs++;
// Get max changed version and chunk version
if (chunkVersion > *_maxVersion) {
*_maxVersion = chunkVersion;
}
// Chunk version changes
ShardId shard = shardFor(txn, chunk.getShard());
typename MaxChunkVersionMap::const_iterator shardVersionIt = _maxShardVersions->find(shard);
if (shardVersionIt == _maxShardVersions->end() || shardVersionIt->second < chunkVersion) {
(*_maxShardVersions)[shard] = chunkVersion;
}
// See if we need to remove any chunks we are currently tracking because of this chunk's
// changes
{
RangeOverlap overlap = _overlappingRange(chunk.getMin(), chunk.getMax());
_currMap->erase(overlap.first, overlap.second);
}
// Figure out which of the new chunks we need to track
// Important - we need to actually own this doc, in case the cursor decides to getMore
// or unbuffer.
if (isTracked(chunk)) {
newTracked.push_back(chunk);
}
}
LOG(3) << "found " << _validDiffs << " new chunks for collection " << _ns << " (tracking "
<< newTracked.size() << "), new version is " << *_maxVersion;
for (const ChunkType& chunk : newTracked) {
// Invariant enforced by sharding - it's possible to read inconsistent state due to
// getMore and yielding, so we want to detect it as early as possible.
//
// TODO: This checks for overlap, we also should check for holes here iff we're
// tracking all chunks.
if (_isOverlapping(chunk.getMin(), chunk.getMax())) {
return -1;
}
_currMap->insert(rangeFor(txn, chunk));
}
return _validDiffs;
}
ConfigDiffTrackerBase::QueryAndSort ConfigDiffTrackerBase::createConfigDiffQuery(
const NamespaceString& nss, ChunkVersion collectionVersion) {
// The query has to find all the chunks $gte the current max version. Currently, any splits and
// merges will increment the current max version.
BSONObjBuilder queryB;
queryB.append(ChunkType::ns(), nss.ns());
{
BSONObjBuilder tsBuilder(queryB.subobjStart(ChunkType::DEPRECATED_lastmod()));
tsBuilder.appendTimestamp("$gte", collectionVersion.toLong());
tsBuilder.done();
}
// NOTE: IT IS IMPORTANT FOR CONSISTENCY THAT WE SORT BY ASC VERSION, IN ORDER TO HANDLE CURSOR
// YIELDING BETWEEN CHUNKS BEING MIGRATED
//
// This ensures that changes to chunk version (which will always be higher) will always come
// *after* our current position in the chunk cursor.
return QueryAndSort{queryB.obj(), BSON(ChunkType::DEPRECATED_lastmod() << 1)};
}
// Ensures that these instances of the template are compiled
class Chunk;
template class ConfigDiffTracker<BSONObj>;
template class ConfigDiffTracker<CachedChunkInfo>;
template class ConfigDiffTracker<std::shared_ptr<Chunk>>;
} // namespace mongo
|
