Good job for figuring this out! This certainly seems to explain our problems.
Thanks! Gyula Aljoscha Krettek <aljos...@apache.org> ezt írta (időpont: 2017. szept. 14., Cs, 14:46): > After a bit more digging I found that the "isRestored" flag doesn't work > correctly if there are operators chained to the sink that have state: > https://issues.apache.org/jira/browse/FLINK-7623 > > Blocker issue for 1.3.3 and 1.4.0. > > Best, > Aljoscha > > On 6. Sep 2017, at 16:05, Aljoscha Krettek <aljos...@apache.org> wrote: > > After discussing this between Stefan and me we think that this should > actually work. > > Do you have the log output from restoring the Kafka Consumer? It would be > interesting to see whether any of those print: > - > https://github.com/apache/flink/blob/f1a173addd99e5df00921b924352a39810d8d180/flink-connectors/flink-connector-kafka-base/src/main/java/org/apache/flink/streaming/connectors/kafka/FlinkKafkaConsumerBase.java#L611 > - > https://github.com/apache/flink/blob/f1a173addd99e5df00921b924352a39810d8d180/flink-connectors/flink-connector-kafka-base/src/main/java/org/apache/flink/streaming/connectors/kafka/FlinkKafkaConsumerBase.java#L554 > > On 6. Sep 2017, at 14:45, Aljoscha Krettek <aljos...@apache.org> wrote: > > Yes, and that's essentially what's happening in the 1.4-SNAPSHOT consumer > which also has discovery of new partitions. Starting from 1.4-SNAPSHOT we > store state in a union state, i.e. all sources get all partition on restore > and if they didn't get any they know that they are new. There is no > specific logic for detecting this situation, it's just that the partition > discoverer will be seeded with this information and it will know if it > discovers a new partition whether it can take ownership of that partition. > > I'm sure Gordon (cc'ed) could explain it better than I did. > > On 6. Sep 2017, at 14:36, Gyula Fóra <gyf...@apache.org> wrote: > > Wouldnt it be enough that Kafka sources store some empty container for > there state if it is empty, compared to null when it should be bootstrapped > again? > > Gyula > > Aljoscha Krettek <aljos...@apache.org> ezt írta (időpont: 2017. szept. > 6., Sze, 14:31): > >> The problem here is that context.isRestored() is a global flag and not >> local to each operator. It says "yes this job was restored" but the source >> would need to know that it is actually brand new and never had any state. >> This is quite tricky to do, since there is currently no way (if I'm >> correct) to differentiate between "I got empty state but others maybe got >> state" and "this source never had state and neither had other parallel >> instances". >> >> Best, >> Aljoscha >> >> On 6. Sep 2017, at 13:56, Stefan Richter <s.rich...@data-artisans.com> >> wrote: >> >> Thanks for the report, I will take a look. >> >> Am 06.09.2017 um 11:48 schrieb Gyula Fóra <gyf...@apache.org>: >> >> Hi all, >> >> We are running into some problems with the kafka source after changing >> the uid and restoring from the savepoint. >> What we are expecting is to clear the partition state, and set it up all >> over again, but what seems to happen is that the consumer thinks that it >> doesnt have any partitions assigned. >> >> This was supposed to be fixed in >> https://github.com/apache/flink/commit/0ecb5d0050b84ba48105836288d43ce4c4749459#diff-06bf4a7f73d98ef91309154654563475 >> but appears to be reworked/reverted in the latest release : >> https://github.com/apache/flink/blob/0399beed1ea3e04d332b42cc506041d75a6148b4/flink-connectors/flink-connector-kafka-base/src/main/java/org/apache/flink/streaming/connectors/kafka/FlinkKafkaConsumerBase.java#L547 >> >> What is the expected behaviour here? >> >> Thanks! >> Gyula >> >> >> >> > > >
