Thanks Greg. I'll look into it more tomorrow. Just finding it difficult to reproduce in a test. Thanks for providing the sequence, gives me something to try and repo. Appreciated.
Thanks, Damian On Wed, 5 Jul 2017 at 19:57, Greg Fodor <gfo...@gmail.com> wrote: > Also, the sequence of events is: > > - Job starts, rebalance happens, things run along smoothly. > - After 10 minutes (retrospectively) the cleanup task kicks on and removes > some directories > - Tasks immediately start failing when trying to flush their state stores > > > > On Wed, Jul 5, 2017 at 11:55 AM, Greg Fodor <gfo...@gmail.com> wrote: > > > The issue I am hitting is not the directory locking issues we've seen in > > the past. The issue seems to be, as you mentioned, that the state dir is > > getting deleted by the store cleanup process, but there are still tasks > > running that are trying to flush the state store. It seems more than a > > little scary given that right now it seems either a) there are tasks > > running that should have been re-assigned or b) the cleanup job is > removing > > state directories for currently running + assigned tasks (perhaps during > a > > rebalance there is a race condition?) I'm guessing there's probably a > more > > benign explanation, but that is what it looks like right now. > > > > On Wed, Jul 5, 2017 at 7:00 AM, Damian Guy <damian....@gmail.com> wrote: > > > >> BTW - i'm trying to reproduce it, but not having much luck so far... > >> > >> On Wed, 5 Jul 2017 at 09:27 Damian Guy <damian....@gmail.com> wrote: > >> > >> > Thans for the updates Greg. There were some minor changes around this > in > >> > 0.11.0 to make it less likely to happen, but we've only ever seen the > >> > locking fail in the event of a rebalance. When everything is running > >> state > >> > dirs shouldn't be deleted if they are being used as the lock will > fail. > >> > > >> > > >> > On Wed, 5 Jul 2017 at 08:15 Greg Fodor <gfo...@gmail.com> wrote: > >> > > >> >> I can report that setting state.cleanup.delay.ms to a very large > value > >> >> (effectively disabling it) works around the issue. It seems that the > >> state > >> >> store cleanup process can somehow get out ahead of another task that > >> still > >> >> thinks it should be writing to the state store/flushing it. In my > test > >> >> runs, this does not seem to be happening during a rebalancing event, > >> but > >> >> after the cluster is stable. > >> >> > >> >> On Tue, Jul 4, 2017 at 12:29 PM, Greg Fodor <gfo...@gmail.com> > wrote: > >> >> > >> >> > Upon another run, I see the same error occur during a rebalance, so > >> >> either > >> >> > my log was showing a rebalance or there is a shared underlying > issue > >> >> with > >> >> > state stores. > >> >> > > >> >> > On Tue, Jul 4, 2017 at 11:35 AM, Greg Fodor <gfo...@gmail.com> > >> wrote: > >> >> > > >> >> >> Also, I am on 0.10.2.1, so poll interval was already set to > >> MAX_VALUE. > >> >> >> > >> >> >> On Tue, Jul 4, 2017 at 11:28 AM, Greg Fodor <gfo...@gmail.com> > >> wrote: > >> >> >> > >> >> >>> I've nuked the nodes this happened on, but the job had been > running > >> >> for > >> >> >>> about 5-10 minutes across 5 nodes before this happened. Does the > >> log > >> >> show a > >> >> >>> rebalance was happening? It looks to me like the standby task was > >> just > >> >> >>> committing as part of normal operations. > >> >> >>> > >> >> >>> On Tue, Jul 4, 2017 at 7:40 AM, Damian Guy <damian....@gmail.com > > > >> >> wrote: > >> >> >>> > >> >> >>>> Hi Greg, > >> >> >>>> > >> >> >>>> Obviously a bit difficult to read the RocksDBException, but my > >> guess > >> >> is > >> >> >>>> it > >> >> >>>> is because the state directory gets deleted right before the > flush > >> >> >>>> happens: > >> >> >>>> 2017-07-04 10:54:46,829 [myid:] - INFO > >> >> [StreamThread-21:StateDirector > >> >> >>>> y@213] > >> >> >>>> - Deleting obsolete state directory 0_10 for task 0_10 > >> >> >>>> > >> >> >>>> Yes it looks like it is possibly the same bug as KAFKA-5070. > >> >> >>>> > >> >> >>>> It looks like your application is constantly rebalancing during > >> store > >> >> >>>> intialization, which may be the reason this bug comes about > (there > >> >> is a > >> >> >>>> chance that the state dir lock is released so when the thread > >> tries > >> >> to > >> >> >>>> removes the stale state directory it is able to get the lock). > You > >> >> >>>> probably > >> >> >>>> want to configure `max.poll.interval.ms` to be a reasonably > large > >> >> >>>> value ( i > >> >> >>>> think we default to Integer.MAX_VALUE in 0.10.2.1). You can also > >> try > >> >> >>>> setting `state.cleanup.delay.ms` to a higher value (default is > 10 > >> >> >>>> minutes), > >> >> >>>> to try and avoid it happening during a rebalance (I know this > >> isn't a > >> >> >>>> fix, > >> >> >>>> but will make it less likely to happen). > >> >> >>>> > >> >> >>>> Thanks, > >> >> >>>> Damian > >> >> >>>> > >> >> >>>> On Tue, 4 Jul 2017 at 12:43 Greg Fodor <gfo...@gmail.com> > wrote: > >> >> >>>> > >> >> >>>> > Hi all, we are working on upgrading our jobs from 0.10.0 to > use > >> >> Kafka > >> >> >>>> > Streams 0.10.2.1 and are hitting a problem. We have an ETL job > >> that > >> >> >>>> has 4 > >> >> >>>> > state stores and runs across a few hundred partitions, and as > >> part > >> >> of > >> >> >>>> load > >> >> >>>> > testing the job we are trying to reload our data out of kafka > >> into > >> >> a > >> >> >>>> test > >> >> >>>> > db. The result is we are able to load about 4M tuples and then > >> this > >> >> >>>> error > >> >> >>>> > pops up on all of the stream nodes simultaneously. There are 4 > >> >> rocksdb > >> >> >>>> > stores in question and there are lots of these errors which > >> takes > >> >> it > >> >> >>>> down. > >> >> >>>> > This bug *does* not seem to occur on 0.10.1. > >> >> >>>> > > >> >> >>>> > A similar error was mentioned here: > >> >> >>>> > https://issues.apache.org/jira/browse/KAFKA-5070 > >> >> >>>> > > >> >> >>>> > Full log attached. > >> >> >>>> > > >> >> >>>> > org.apache.kafka.streams.errors.ProcessorStateException: task > >> >> [0_10] > >> >> >>>> > Failed to flush state store session-id-start-events > >> >> >>>> > at > >> >> >>>> > org.apache.kafka.streams.processor.internals.ProcessorStateM > >> >> >>>> anager.flush(ProcessorStateManager.java:337) > >> >> >>>> > at > >> >> >>>> > org.apache.kafka.streams.processor.internals.StandbyTask.com > >> >> >>>> mit(StandbyTask.java:94) > >> >> >>>> > at > >> >> >>>> > org.apache.kafka.streams.processor.internals.StreamThread.co > >> >> >>>> mmitOne(StreamThread.java:807) > >> >> >>>> > at > >> >> >>>> > org.apache.kafka.streams.processor.internals.StreamThread.co > >> >> >>>> mmitAll(StreamThread.java:797) > >> >> >>>> > at > >> >> >>>> > org.apache.kafka.streams.processor.internals.StreamThread.ma > >> >> >>>> ybeCommit(StreamThread.java:769) > >> >> >>>> > at > >> >> >>>> > org.apache.kafka.streams.processor.internals.StreamThread.ru > >> >> >>>> nLoop(StreamThread.java:647) > >> >> >>>> > at > >> >> >>>> > org.apache.kafka.streams.processor.internals.StreamThread.ru > >> >> >>>> n(StreamThread.java:361) > >> >> >>>> > Caused by: org.apache.kafka.streams.error > >> s.ProcessorStateException: > >> >> >>>> Error > >> >> >>>> > while executing flush from store session-id-start-events > >> >> >>>> > at > >> >> >>>> > org.apache.kafka.streams.state.internals.RocksDBStore.flushI > >> >> >>>> nternal(RocksDBStore.java:354) > >> >> >>>> > at > >> >> >>>> > org.apache.kafka.streams.state.internals.RocksDBStore.flush( > >> >> >>>> RocksDBStore.java:345) > >> >> >>>> > at > >> >> >>>> > org.apache.kafka.streams.state.internals.WrappedStateStore$A > >> >> >>>> bstractWrappedStateStore.flush(WrappedStateStore.java:80) > >> >> >>>> > at > >> >> >>>> > org.apache.kafka.streams.state.internals.WrappedStateStore$A > >> >> >>>> bstractWrappedStateStore.flush(WrappedStateStore.java:80) > >> >> >>>> > at > >> >> >>>> > org.apache.kafka.streams.state.internals.MeteredKeyValueStor > >> >> >>>> e$6.run(MeteredKeyValueStore.java:92) > >> >> >>>> > at > >> >> >>>> > org.apache.kafka.streams.processor.internals.StreamsMetricsI > >> >> >>>> mpl.measureLatencyNs(StreamsMetricsImpl.java:188) > >> >> >>>> > at > >> >> >>>> > org.apache.kafka.streams.state.internals.MeteredKeyValueStor > >> >> >>>> e.flush(MeteredKeyValueStore.java:186) > >> >> >>>> > at > >> >> >>>> > org.apache.kafka.streams.processor.internals.ProcessorStateM > >> >> >>>> anager.flush(ProcessorStateManager.java:335) > >> >> >>>> > ... 6 more > >> >> >>>> > Caused by: org.rocksdb.RocksDBException: v > >> >> >>>> > at org.rocksdb.RocksDB.flush(Native Method) > >> >> >>>> > at org.rocksdb.RocksDB.flush(RocksDB.java:1642) > >> >> >>>> > at > >> >> >>>> > org.apache.kafka.streams.state.internals.RocksDBStore.flushI > >> >> >>>> nternal(RocksDBStore.java:352) > >> >> >>>> > ... 13 more > >> >> >>>> > > >> >> >>>> > > >> >> >>>> > >> >> >>> > >> >> >>> > >> >> >> > >> >> > > >> >> > >> > > >> > > > > >
