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
221
222
223
224
225
226
227
228
229
|
/**
* Copyright 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.
*/
#define MONGO_LOG_DEFAULT_COMPONENT ::mongo::logger::LogComponent::kReplication
#include "mongo/platform/basic.h"
#include "mongo/db/repl/freshness_checker.h"
#include "mongo/base/status.h"
#include "mongo/bson/timestamp.h"
#include "mongo/db/repl/repl_set_config.h"
#include "mongo/db/repl/scatter_gather_runner.h"
#include "mongo/rpc/get_status_from_command_result.h"
#include "mongo/util/log.h"
#include "mongo/util/scopeguard.h"
#include "mongo/util/time_support.h"
namespace mongo {
namespace repl {
using executor::RemoteCommandRequest;
using executor::RemoteCommandResponse;
FreshnessChecker::Algorithm::Algorithm(Timestamp lastOpTimeApplied,
const ReplSetConfig& rsConfig,
int selfIndex,
const std::vector<HostAndPort>& targets)
: _responsesProcessed(0),
_failedVoterResponses(0),
_lastOpTimeApplied(lastOpTimeApplied),
_rsConfig(rsConfig),
_selfIndex(selfIndex),
_targets(targets),
_votingTargets(0),
_losableVoters(0),
_myVote(0),
_abortReason(None) {
// Count voting targets (since the targets could be a subset of members).
for (std::vector<HostAndPort>::const_iterator it = _targets.begin(); it != _targets.end();
++it) {
const MemberConfig* member = _rsConfig.findMemberByHostAndPort(*it);
if (member && member->isVoter())
++_votingTargets;
}
_myVote = _rsConfig.getMemberAt(_selfIndex).isVoter() ? 1 : 0;
_losableVoters = std::max(0, ((_votingTargets + _myVote) - _rsConfig.getMajorityVoteCount()));
}
FreshnessChecker::Algorithm::~Algorithm() {}
std::vector<RemoteCommandRequest> FreshnessChecker::Algorithm::getRequests() const {
const MemberConfig& selfConfig = _rsConfig.getMemberAt(_selfIndex);
// gather all not-down nodes, get their fullnames(or hostandport's)
// schedule fresh command for each node
BSONObjBuilder freshCmdBuilder;
freshCmdBuilder.append("replSetFresh", 1);
freshCmdBuilder.append("set", _rsConfig.getReplSetName());
freshCmdBuilder.append("opTime", Date_t::fromMillisSinceEpoch(_lastOpTimeApplied.asLL()));
freshCmdBuilder.append("who", selfConfig.getHostAndPort().toString());
freshCmdBuilder.appendIntOrLL("cfgver", _rsConfig.getConfigVersion());
freshCmdBuilder.append("id", selfConfig.getId());
const BSONObj replSetFreshCmd = freshCmdBuilder.obj();
std::vector<RemoteCommandRequest> requests;
for (std::vector<HostAndPort>::const_iterator it = _targets.begin(); it != _targets.end();
++it) {
invariant(*it != selfConfig.getHostAndPort());
requests.push_back(RemoteCommandRequest(
*it,
"admin",
replSetFreshCmd,
nullptr,
Milliseconds(30 * 1000))); // trying to match current Socket timeout
}
return requests;
}
bool FreshnessChecker::Algorithm::hadTooManyFailedVoterResponses() const {
const bool tooManyLostVoters = (_failedVoterResponses > _losableVoters);
LOG(3) << "hadTooManyFailedVoterResponses(" << tooManyLostVoters
<< ") = " << _failedVoterResponses << " failed responses <"
<< " (" << _votingTargets << " total voters - " << _rsConfig.getMajorityVoteCount()
<< " majority voters - me (" << _myVote << ")) -- losableVotes: " << _losableVoters;
return tooManyLostVoters;
}
bool FreshnessChecker::Algorithm::_isVotingMember(const HostAndPort hap) const {
const MemberConfig* member = _rsConfig.findMemberByHostAndPort(hap);
invariant(member);
return member->isVoter();
}
void FreshnessChecker::Algorithm::processResponse(const RemoteCommandRequest& request,
const RemoteCommandResponse& response) {
++_responsesProcessed;
bool votingMember = _isVotingMember(request.target);
Status status = Status::OK();
if (!response.isOK() || !((status = getStatusFromCommandResult(response.data)).isOK())) {
if (votingMember) {
++_failedVoterResponses;
if (hadTooManyFailedVoterResponses()) {
_abortReason = QuorumUnreachable;
}
}
if (!response.isOK()) { // network/executor error
LOG(2) << "FreshnessChecker: Got failed response from " << request.target;
} else { // command error, like unauth
LOG(2) << "FreshnessChecker: Got error response from " << request.target << " :"
<< status;
}
return;
}
const BSONObj res = response.data;
LOG(2) << "FreshnessChecker: Got response from " << request.target << " of " << res;
if (res["fresher"].trueValue()) {
log() << "not electing self, " << request.target.toString()
<< " knows a node is fresher than us";
_abortReason = FresherNodeFound;
return;
}
if (res["opTime"].type() != mongo::Date) {
error() << "wrong type for opTime argument in replSetFresh response: "
<< typeName(res["opTime"].type());
_abortReason = FresherNodeFound;
return;
}
Timestamp remoteTime(res["opTime"].date());
if (remoteTime == _lastOpTimeApplied) {
log() << "not electing self, " << request.target.toString()
<< " has same OpTime as us: " << remoteTime.toBSON();
_abortReason = FreshnessTie;
}
if (remoteTime > _lastOpTimeApplied) {
// something really wrong (rogue command?)
log() << "not electing self, " << request.target.toString()
<< " has newer OpTime than us. Our OpTime: " << _lastOpTimeApplied.toBSON()
<< ", their OpTime: " << remoteTime.toBSON();
_abortReason = FresherNodeFound;
return;
}
if (res["veto"].trueValue()) {
BSONElement msg = res["errmsg"];
if (msg.type() == String) {
log() << "not electing self, " << request.target.toString() << " would veto with '"
<< msg.String() << "'";
} else {
log() << "not electing self, " << request.target.toString() << " would veto";
}
_abortReason = FresherNodeFound;
return;
}
}
bool FreshnessChecker::Algorithm::hasReceivedSufficientResponses() const {
return (_abortReason != None && _abortReason != FreshnessTie) ||
(_responsesProcessed == static_cast<int>(_targets.size()));
}
FreshnessChecker::ElectionAbortReason FreshnessChecker::Algorithm::shouldAbortElection() const {
return _abortReason;
}
FreshnessChecker::ElectionAbortReason FreshnessChecker::shouldAbortElection() const {
return _algorithm->shouldAbortElection();
}
long long FreshnessChecker::getOriginalConfigVersion() const {
return _originalConfigVersion;
}
FreshnessChecker::FreshnessChecker() : _isCanceled(false) {}
FreshnessChecker::~FreshnessChecker() {}
StatusWith<executor::TaskExecutor::EventHandle> FreshnessChecker::start(
executor::TaskExecutor* executor,
const Timestamp& lastOpTimeApplied,
const ReplSetConfig& currentConfig,
int selfIndex,
const std::vector<HostAndPort>& targets) {
_originalConfigVersion = currentConfig.getConfigVersion();
_algorithm.reset(new Algorithm(lastOpTimeApplied, currentConfig, selfIndex, targets));
_runner.reset(new ScatterGatherRunner(_algorithm.get(), executor));
return _runner->start();
}
void FreshnessChecker::cancel() {
_isCanceled = true;
_runner->cancel();
}
} // namespace repl
} // namespace mongo
|
