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
230
231
232
233
234
235
236
237
238
239
240
|
/**
* Copyright (C) 2018-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.
*/
#define MONGO_LOG_DEFAULT_COMPONENT ::mongo::logger::LogComponent::kStorage
#include "mongo/platform/basic.h"
#include <string>
#include "mongo/db/concurrency/d_concurrency.h"
#include "mongo/db/concurrency/write_conflict_exception.h"
#include "mongo/db/operation_context.h"
#include "mongo/db/storage/mobile/mobile_options.h"
#include "mongo/db/storage/mobile/mobile_recovery_unit.h"
#include "mongo/db/storage/mobile/mobile_sqlite_statement.h"
#include "mongo/db/storage/mobile/mobile_util.h"
#include "mongo/db/storage/sorted_data_interface.h"
#include "mongo/util/log.h"
#define RECOVERY_UNIT_TRACE() LOG(MOBILE_TRACE_LEVEL) << "MobileSE: RecoveryUnit ID:" << _id << " "
namespace mongo {
AtomicWord<long long> MobileRecoveryUnit::_nextID(0);
MobileRecoveryUnit::MobileRecoveryUnit(MobileSessionPool* sessionPool)
: _isReadOnly(true), _sessionPool(sessionPool) {
// Increment the global instance count and assign this instance an id.
_id = _nextID.addAndFetch(1);
RECOVERY_UNIT_TRACE() << "Created.";
}
MobileRecoveryUnit::~MobileRecoveryUnit() {
invariant(!_inUnitOfWork(), toString(_getState()));
_abort();
RECOVERY_UNIT_TRACE() << "Destroyed.";
}
void MobileRecoveryUnit::_commit() {
if (_session && _isActive()) {
_txnClose(true);
}
_setState(State::kCommitting);
commitRegisteredChanges(boost::none);
_setState(State::kInactive);
}
void MobileRecoveryUnit::_abort() {
if (_session && _isActive()) {
_txnClose(false);
}
_setState(State::kAborting);
abortRegisteredChanges();
invariant(!_isActive(), toString(_getState()));
_setState(State::kInactive);
}
void MobileRecoveryUnit::beginUnitOfWork(OperationContext* opCtx) {
invariant(!_inUnitOfWork(), toString(_getState()));
RECOVERY_UNIT_TRACE() << "Unit of work Active.";
if (_isActive()) {
// Confirm a write transaction is not running
invariant(_isReadOnly);
// Rollback read transaction running outside wuow
_txnClose(false);
}
_setState(State::kInactiveInUnitOfWork);
_txnOpen(opCtx, false);
}
void MobileRecoveryUnit::commitUnitOfWork() {
invariant(_inUnitOfWork(), toString(_getState()));
RECOVERY_UNIT_TRACE() << "Unit of work commited, marked inactive.";
_commit();
}
void MobileRecoveryUnit::abortUnitOfWork() {
invariant(_inUnitOfWork(), toString(_getState()));
RECOVERY_UNIT_TRACE() << "Unit of work aborted, marked inactive.";
_abort();
}
bool MobileRecoveryUnit::waitUntilDurable(OperationContext* opCtx) {
// This is going to be slow as we're taking a global X lock and doing a full checkpoint. This
// should not be needed to do on Android or iOS if we are on WAL and synchronous=NORMAL which
// are our default settings. The system will make sure any non-flushed writes will not be lost
// before going down but our powercycle test bench require it. Therefore make sure embedded does
// not call this (by disabling writeConcern j:true) but allow it when this is used inside
// mongod.
if (_sessionPool->getOptions().durabilityLevel < 2) {
_ensureSession(opCtx);
RECOVERY_UNIT_TRACE() << "waitUntilDurable called, attempting to perform a checkpoint";
int framesInWAL = 0;
int checkpointedFrames = 0;
int ret;
{
Lock::GlobalLock lk(opCtx, MODE_X);
// Use FULL mode to guarantee durability
ret = sqlite3_wal_checkpoint_v2(_session.get()->getSession(),
nullptr,
SQLITE_CHECKPOINT_FULL,
&framesInWAL,
&checkpointedFrames);
}
embedded::checkStatus(ret, SQLITE_OK, "sqlite3_wal_checkpoint_v2");
fassert(51164,
framesInWAL != -1 && checkpointedFrames != -1 && framesInWAL == checkpointedFrames);
RECOVERY_UNIT_TRACE() << "Checkpointed " << checkpointedFrames << " of the " << framesInWAL
<< " total frames in the WAL";
} else {
RECOVERY_UNIT_TRACE() << "No checkpoint attempted -- in full synchronous mode";
}
return true;
}
void MobileRecoveryUnit::abandonSnapshot() {
invariant(!_inUnitOfWork(), toString(_getState()));
if (_isActive()) {
// We can't be in a WriteUnitOfWork, so it is safe to rollback.
_txnClose(false);
}
_setState(State::kInactive);
}
MobileSession* MobileRecoveryUnit::getSession(OperationContext* opCtx, bool readOnly) {
RECOVERY_UNIT_TRACE() << "getSession called with readOnly:" << (readOnly ? "TRUE" : "FALSE");
invariant(_inUnitOfWork() || readOnly);
if (!_isActive()) {
_txnOpen(opCtx, readOnly);
}
return _session.get();
}
MobileSession* MobileRecoveryUnit::getSessionNoTxn(OperationContext* opCtx) {
_ensureSession(opCtx);
return _session.get();
}
void MobileRecoveryUnit::assertInActiveTxn() const {
fassert(37050, _isActive());
}
void MobileRecoveryUnit::_ensureSession(OperationContext* opCtx) {
RECOVERY_UNIT_TRACE() << "Creating new session:" << (_session ? "NO" : "YES");
if (!_session) {
_session = _sessionPool->getSession(opCtx);
}
}
void MobileRecoveryUnit::_txnOpen(OperationContext* opCtx, bool readOnly) {
invariant(!_isActive(), toString(_getState()));
RECOVERY_UNIT_TRACE() << "_txnOpen called with readOnly:" << (readOnly ? "TRUE" : "FALSE");
_ensureSession(opCtx);
/*
* Starting a transaction with the "BEGIN" statement doesn't take an immediate lock.
* SQLite defers taking any locks until the database is first accessed. This creates the
* possibility of having multiple transactions opened in parallel. All sessions except the
* first to request the access get a database locked error.
* However, "BEGIN IMMEDIATE" forces SQLite to take a lock immediately. If another session
* tries to create a transaction in parallel, it receives a busy error and then retries.
* Reads outside these explicit transactions proceed unaffected.
*/
// Check for correct locking at higher levels
if (readOnly) {
// Confirm that this reader has taken a shared lock
if (!opCtx->lockState()->isLockHeldForMode(resourceIdGlobal, MODE_S)) {
opCtx->lockState()->dump();
invariant(!"Reading without a shared lock");
}
SqliteStatement::execQuery(_session.get(), "BEGIN");
} else {
// Single writer allowed at a time, confirm a global write lock has been taken
if (!opCtx->lockState()->isLockHeldForMode(resourceIdGlobal, MODE_X)) {
opCtx->lockState()->dump();
invariant(!"Writing without an exclusive lock");
}
SqliteStatement::execQuery(_session.get(), "BEGIN EXCLUSIVE");
}
_isReadOnly = readOnly;
_setState(_inUnitOfWork() ? State::kActive : State::kActiveNotInUnitOfWork);
}
void MobileRecoveryUnit::_txnClose(bool commit) {
invariant(_isActive(), toString(_getState()));
RECOVERY_UNIT_TRACE() << "_txnClose called with " << (commit ? "commit " : "rollback ");
if (commit) {
SqliteStatement::execQuery(_session.get(), "COMMIT");
} else {
SqliteStatement::execQuery(_session.get(), "ROLLBACK");
}
_isReadOnly = true; // I don't suppose we need this, but no harm in doing so
}
void MobileRecoveryUnit::enqueueFailedDrop(std::string& dropQuery) {
_sessionPool->failedDropsQueue.enqueueOp(dropQuery);
}
} // namespace mongo
|
