void NoopWriter::_writeNoop(OperationContext* opCtx) {
// Use GlobalLock + lockMMAPV1Flush instead of DBLock to allow return when the lock is not
// available. It may happen when the primary steps down and a shared global lock is acquired.
Lock::GlobalLock lock(
opCtx, MODE_IX, Date_t::now() + Milliseconds(1), Lock::InterruptBehavior::kLeaveUnlocked);
if (!lock.isLocked()) {
LOG(1) << "Global lock is not available skipping noopWrite";
return;
}
opCtx->lockState()->lockMMAPV1Flush();
auto replCoord = ReplicationCoordinator::get(opCtx);
// Its a proxy for being a primary
if (!replCoord->canAcceptWritesForDatabase(opCtx, "admin")) {
LOG(1) << "Not a primary, skipping the noop write";
return;
}
auto lastAppliedOpTime = replCoord->getMyLastAppliedOpTime();
// _lastKnownOpTime is not protected by lock as its used only by one thread.
if (lastAppliedOpTime != _lastKnownOpTime) {
LOG(1) << "Not scheduling a noop write. Last known OpTime: " << _lastKnownOpTime
<< " != last primary OpTime: " << lastAppliedOpTime;
} else {
if (writePeriodicNoops.load()) {
const auto logLevel = getTestCommandsEnabled() ? 0 : 1;
LOG(logLevel)
<< "Writing noop to oplog as there has been no writes to this replica set in over "
<< _writeInterval;
writeConflictRetry(
opCtx, "writeNoop", NamespaceString::kRsOplogNamespace.ns(), [&opCtx] {
WriteUnitOfWork uow(opCtx);
opCtx->getClient()->getServiceContext()->getOpObserver()->onOpMessage(opCtx,
kMsgObj);
uow.commit();
});
}
}
_lastKnownOpTime = replCoord->getMyLastAppliedOpTime();
LOG(1) << "Set last known op time to " << _lastKnownOpTime;
}
void ReplicationCoordinatorImpl::_recoverFromElectionTie(
const ReplicationExecutor::CallbackArgs& cbData) {
LockGuard topoLock(_topoMutex);
auto now = _replExecutor.now();
auto lastOpApplied = getMyLastAppliedOpTime();
const auto status = _topCoord->checkShouldStandForElection(now, lastOpApplied);
if (!status.isOK()) {
LOG(2) << "ReplicationCoordinatorImpl::_recoverFromElectionTie -- " << status.reason();
} else {
fassertStatusOK(28817, _topCoord->becomeCandidateIfElectable(now, lastOpApplied, false));
_startElectSelf();
}
}
void ReplicationCoordinatorImpl::_startVoteRequester(long long newTerm) {
invariant(_voteRequester);
LoseElectionGuardV1 lossGuard(this);
LockGuard lk(_topoMutex);
const auto lastOpTime =
_isDurableStorageEngine() ? getMyLastDurableOpTime() : getMyLastAppliedOpTime();
_voteRequester.reset(new VoteRequester);
StatusWith<ReplicationExecutor::EventHandle> nextPhaseEvh = _voteRequester->start(
&_replExecutor, _rsConfig, _selfIndex, _topCoord->getTerm(), false, lastOpTime);
if (nextPhaseEvh.getStatus() == ErrorCodes::ShutdownInProgress) {
return;
}
fassert(28643, nextPhaseEvh.getStatus());
_replExecutor.onEvent(
nextPhaseEvh.getValue(),
stdx::bind(&ReplicationCoordinatorImpl::_onVoteRequestComplete, this, newTerm));
lossGuard.dismiss();
}