We had some discussion on the Jira Issue when I changed the translation from operators to StreamGraph: https://issues.apache.org/jira/browse/FLINK-2398
There are arguments for both ways of doing it, I'm not partial towards any solution but if you want this changed you can start a discussion. (If we change it, however, this will probably not come in time for 0.10) On Thu, 8 Oct 2015 at 16:42 Matthias J. Sax <mj...@apache.org> wrote: > Dropping would be less strange. > > However, raising an exception would be natural (at least to me) > > > On 10/08/2015 04:30 PM, Aljoscha Krettek wrote: > > What do you mean? The current behavior is strange or the other way round > would be strange? > > > > I think it is in line with what other Stream Processing Systems provide. > For example Storm and Google Dataflow behave similarly. > > > >> On 08 Oct 2015, at 16:25, Matthias J. Sax <mj...@apache.org> wrote: > >> > >> Well. This behavior would also be kind of strange... (at least to me) > >> > >> On 10/08/2015 04:22 PM, Aljoscha Krettek wrote: > >>> Hi, > >>> I think Flink does in fact not drop the dangling parts. In streaming > it is allowed to have dangling operators that are not sinks. They are > executed and the output is just discarded. > >>> > >>> Cheers, > >>> Aljoscha > >>>> On 08 Oct 2015, at 16:18, Matthias J. Sax <mj...@apache.org> wrote: > >>>> > >>>> Hi, > >>>> > >>>> I just hit a problem in Storm Compatibility: > >>>> https://issues.apache.org/jira/browse/FLINK-2837 > >>>> > >>>> If a bolt has multiple inputs, the topology is not translated > correctly > >>>> into a Flink streaming program. The point is, that the Flink program > can > >>>> be executed without an error, even if the assembled data flow has > >>>> dangling parts... > >>>> > >>>> For example: > >>>> > >>>> Source1 --+--+--> Bolt --> SinkBolt > >>>> | | > >>>> Source2 --+ | > >>>> | > >>>> Source3 -----+ > >>>> > >>>> Is translated to the following Flink program > >>>> > >>>> Source1 --> Bolt --> SinkBolt > >>>> > >>>> Source2 --> Bolt > >>>> > >>>> Source3 --> Bolt > >>>> > >>>> with Source2 and Source3 being added to the environment but not > >>>> connected correctly to the overall program because the Bolt is > >>>> instantiated three times and only a single bolt is connect to the > sink. > >>>> It is clear, that Flink just drops the dangling parts, as it builds > the > >>>> JobGraph starting from the sink and traversing backwards. I was just > >>>> wondering, if an error should actually occur. > >>>> > >>>> > >>>> -Matthias > >>>> > >>> > >> > > > >
