Peter All the details you can share on this would be good. First, we should be resilient to any sort of repo corruption in the event of heap issues. While obviously the flow isn't in a good state at that point the saved state should be reliable/recoverable. Second, how the repo/journals got that large itself should be evaluated/considered/determined. A full JIRA/description of the situation/logs/known state would be worthy of further resolution.
Thanks On Thu, Aug 15, 2019 at 12:50 PM Peter Wicks (pwicks) <pwi...@micron.com> wrote: > We were able to recover this morning, in the end we deleted the queues > that were causing trouble from the Flow, and when the problem node came > online it deleted the FlowFile’s all on its own, since the queue did not > exist. Since this is done during the FlowFile Repository load into memory, > it didn’t run out of heap. > > > > But before we go to that point we maxed out heap, 500GB’s! All our server > had to offer. I also tried scripting a cleanup of the journals overflow > files. Which failed, because the journal keeps track of those files, and > won’t restore if some are missing. I’m thinking of building some > nifi-utility functions for doing emergency cleanup of the FlowFile > repository where you can specify a Queue ID and it removes those files, or > maybe doing an offline compaction. > > > > Thanks, > > Peter > > > > > > *From:* Brandon DeVries <b...@jhu.edu> > *Sent:* Thursday, August 15, 2019 9:53 AM > *To:* users@nifi.apache.org > *Subject:* [EXT] Re: FlowFile Repository can't checkpoint, out of heap > space. > > > > > Peter, > > Unfortunately, I don't have a perfect solution for your current problem. > I would try starting with autoResume=false, just to try to limit what's > going on in the system. If possible, you can also try temporarily giving > the JVM more heap. > > This is, however, the use case that led to the idea of "recovery mode" in > the new RocksDBFlowFileRepository[1] that should be in nifi 1.10.0 (the > documentation[2] is attached to the ticket): > > "[Recovery mode] limits the number of FlowFiles loaded into the graph at a > time, while not actually removing any FlowFiles (or content) from the > system. This allows for the recovery of a system that is encountering > OutOfMemory errors or similar on startup..." > > [1] https://issues.apache.org/jira/browse/NIFI-4775 > <https://nam01.safelinks.protection.outlook.com/?url=https%3A%2F%2Fissues.apache.org%2Fjira%2Fbrowse%2FNIFI-4775&data=02%7C01%7Cpwicks%40micron.com%7C2292944c3b9f430c5d9508d72198ab64%7Cf38a5ecd28134862b11bac1d563c806f%7C0%7C0%7C637014811949909503&sdata=EWX6b3fQkHV9ANXRFu7oiiv8n8khDVIy9PT6fiaJmUY%3D&reserved=0> > [2] > https://issues.apache.org/jira/secure/attachment/12976954/RocksDBFlowFileRepo.html > <https://nam01.safelinks.protection.outlook.com/?url=https%3A%2F%2Fissues.apache.org%2Fjira%2Fsecure%2Fattachment%2F12976954%2FRocksDBFlowFileRepo.html&data=02%7C01%7Cpwicks%40micron.com%7C2292944c3b9f430c5d9508d72198ab64%7Cf38a5ecd28134862b11bac1d563c806f%7C0%7C0%7C637014811949909503&sdata=XDKoAcehZmYFqJ6JLVkVyhx0gsRGNyw7vDNfURhsn4E%3D&reserved=0> > > > > On Wed, Aug 14, 2019 at 12:12 PM Peter Wicks (pwicks) <pwi...@micron.com> > wrote: > > I have a node in a cluster whose FlowFile repository grew so fast that it > exceeded the amount of available heap space and now can't checkpoint. Or > that is my interpretation of the error. > > > > "Cannot update journal file flowfile_repository/journals/####.journal > because this journal has already encountered a failure when attempting to > write to the file." > > Additionally, on restart, we see NiFi failed to restart because it ran out > of heap space while doing a SchemaRecordReader.readFieldValue. Feeling a > bit stuck on where to go from here. > > > > Based on metrics we collect, we see a large increase in FlowFile's on that > node right before it crashed, and in linux we see the following: > > 94G ./journals/overflow-569618072 > > 356G ./journals/overflow-569892338 > > > > Oh, and a 280 GB checkpoint file > > > > There are a few queues/known FlowFile’s that are probably the problem, and > I’m OK with dropping them, but there is plenty of other data in there too > that I don’t want to lose… > > > > Thanks, > > Peter > >
