Hi Min, It depends on the source/sink implementation. If the source/sink implementation uses state, uid should be set. So you can always set the uid in this case and then you don't need to care about the implementation details of the source/sink you used.
name() doesn't have such functionality. Regarding to the uid mismatch you encountered, could you share the exception log? Regards, Dian > 在 2019年10月25日，下午3:38，min....@ubs.com 写道： > > Thank you very much for your helpful response. > > Our new production release complains about the an uid mismatch (we use > exactly once checkpoints). > I hope I understand your correctly: map and print are certainly stateless, > therefore no uid is required. What about addSink and addSoure? Do they need > an uid? Or a name() has a similar function? > > Regards, > > Min > > From: Dian Fu [mailto:dian0511...@gmail.com] > Sent: Freitag, 25. Oktober 2019 03:52 > To: Tan, Min > Cc: John Smith; user > Subject: [External] Re: Does operator uid() have to be unique across all jobs? > > Hi Min, > > The uid is used to matching the operator state stored in the > checkpoint/savepoint to an operator[1]. So you only need to specify the uid > for stateful operators. > 1) If you have not specified the uid for an operator, it will generate a uid > for it in a deterministic way[2] for it. The generated uid doesn't change for > the same job. > 2) However, it's encouraged to set uid for stateful operators to allow for > job evolution. The dynamically generated uid is not guaranteed to remain the > same if the job has changed, i.e. adding/removing operators in the job graph. > If you want to reuse state after job evolution, you need to set the uid > explicitly. > > So for the example you give, I think you don't need to specify the uid for > the map and print operator. > > [1] > https://ci.apache.org/projects/flink/flink-docs-master/ops/upgrading.html#matching-operator-state > > <https://ci.apache.org/projects/flink/flink-docs-master/ops/upgrading.html#matching-operator-state> > [2] > https://github.com/apache/flink/blob/fd511c345eac31f03b801ff19dbf1f8c86aae760/flink-streaming-java/src/main/java/org/apache/flink/streaming/api/graph/StreamGraphHasherV2.java#L78 > > <https://protect2.fireeye.com/url?k=c9015cfc22fe1401.c9017582-6f89734a5e8c7c21&u=https://github.com/apache/flink/blob/fd511c345eac31f03b801ff19dbf1f8c86aae760/flink-streaming-java/src/main/java/org/apache/flink/streaming/api/graph/StreamGraphHasherV2.java#L78> > > 在 2019年10月24日，下午11:22，min....@ubs.com <mailto:min....@ubs.com> 写道： > > Hi, > > I have some simple questions on the uid as well. > > 1) Do we add a uid for every operator e.g. print(), addSink and > addSource? > 2) For chained operators, do we need to uids for each operator? Or just > the last operator? > e.g. .map(....).uid("some-id").print().uid("print-id"); > > > Regards, > > Min > > From: John Smith [mailto:java.dev....@gmail.com > <mailto:java.dev....@gmail.com>] > Sent: Donnerstag, 24. Oktober 2019 16:32 > To: Dian Fu > Cc: user > Subject: [External] Re: Does operator uid() have to be unique across all jobs? > > Ok cool. Thanks > > BTW this seems a bit cumbersome... > > .map(....).uid("some-id").name("some-id"); > > On Wed, 23 Oct 2019 at 21:13, Dian Fu <dian0511...@gmail.com > <mailto:dian0511...@gmail.com>> wrote: > Yes, you can use it in another job. The uid needs only to be unique within a > job. > > > 在 2019年10月24日，上午5:42，John Smith <java.dev....@gmail.com > > <mailto:java.dev....@gmail.com>> 写道： > > > > When setting uid() of an operator does it have to be unique across all jobs > > or just unique within a job? > > > > For example can I use env.addSource(myKafkaConsumer).uid("kafka-consumer") > > in another job? > > > E-mails can involve SUBSTANTIAL RISKS, e.g. lack of confidentiality, > potential manipulation of contents and/or sender's address, incorrect > recipient (misdirection), viruses etc. Based on previous e-mail > correspondence with you and/or an agreement reached with you, UBS considers > itself authorized to contact you via e-mail. 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