void BackgroundSync::applyOpsFromOplog() {
GTID lastLiveGTID;
GTID lastUnappliedGTID;
while (1) {
try {
BSONObj curr;
{
boost::unique_lock<boost::mutex> lck(_mutex);
// wait until we know an item has been produced
while (_deque.size() == 0 && !_applierShouldExit) {
_queueDone.notify_all();
_queueCond.wait(lck);
}
if (_deque.size() == 0 && _applierShouldExit) {
return;
}
curr = _deque.front();
}
GTID currEntry = getGTIDFromOplogEntry(curr);
theReplSet->gtidManager->noteApplyingGTID(currEntry);
// we must do applyTransactionFromOplog in a loop
// because once we have called noteApplyingGTID, we must
// continue until we are successful in applying the transaction.
for (uint32_t numTries = 0; numTries <= 100; numTries++) {
try {
numTries++;
TimerHolder timer(&applyBatchStats);
applyTransactionFromOplog(curr);
opsAppliedStats.increment();
break;
}
catch (std::exception &e) {
log() << "exception during applying transaction from oplog: " << e.what() << endl;
log() << "oplog entry: " << curr.str() << endl;
if (numTries == 100) {
// something is really wrong if we fail 100 times, let's abort
::abort();
}
sleepsecs(1);
}
}
LOG(3) << "applied " << curr.toString(false, true) << endl;
theReplSet->gtidManager->noteGTIDApplied(currEntry);
{
boost::unique_lock<boost::mutex> lck(_mutex);
dassert(_deque.size() > 0);
_deque.pop_front();
bufferCountGauge.increment(-1);
bufferSizeGauge.increment(-curr.objsize());
// this is a flow control mechanism, with bad numbers
// hard coded for now just to get something going.
// If the opSync thread notices that we have over 20000
// transactions in the queue, it waits until we get below
// 10000. This is where we signal that we have gotten there
// Once we have spilling of transactions working, this
// logic will need to be redone
if (_deque.size() == 10000) {
_queueCond.notify_all();
}
}
}
catch (DBException& e) {
sethbmsg(str::stream() << "db exception in producer on applier thread: " << e.toString());
sleepsecs(2);
}
catch (std::exception& e2) {
sethbmsg(str::stream() << "exception in producer on applier thread: " << e2.what());
sleepsecs(2);
}
}
}
