Yes, I believe that's what I had in mind. Again, not totally sure it makes sense, but I believe something similar is the rationale for having the partitioner option in Produced.
Thanks, -John On Wed, Jul 17, 2019 at 3:20 PM Levani Kokhreidze <levani.co...@gmail.com> wrote: > > Hey John, > > Oh that’s interesting use-case. > Do I understand this correctly, in your example I would first issue > repartition(Repartitioned) with proper partitioner that essentially would be > the same as the topic I want to join with and then do the KStream#join with > DSL? > > Regards, > Levani > > > On Jul 17, 2019, at 11:11 PM, John Roesler <j...@confluent.io> wrote: > > > > Hey, all, just to chime in, > > > > I think it might be useful to have an option to specify the > > partitioner. The case I have in mind is that some data may get > > repartitioned and then joined with an input topic. If the right-side > > input topic uses a custom partitioning strategy, then the > > repartitioned stream also needs to be partitioned with the same > > strategy. > > > > Does that make sense, or did I maybe miss something important? > > > > Thanks, > > -John > > > > On Wed, Jul 17, 2019 at 2:48 PM Levani Kokhreidze > > <levani.co...@gmail.com> wrote: > >> > >> Yes, I was thinking about it as well. To be honest I’m not sure about it > >> yet. > >> As Kafka Streams DSL user, I don’t really think I would need control over > >> partitioner for internal topics. > >> As a user, I would assume that Kafka Streams knows best how to partition > >> data for internal topics. > >> In this KIP I wrote that Produced should be used only for topics that are > >> created by user In advance. > >> In those cases maybe it make sense to have possibility to specify the > >> partitioner. > >> I don’t have clear answer on that yet, but I guess specifying the > >> partitioner can be added as well if there’s agreement on this. > >> > >> Regards, > >> Levani > >> > >>> On Jul 17, 2019, at 10:42 PM, Sophie Blee-Goldman <sop...@confluent.io> > >>> wrote: > >>> > >>> Thanks for clearing that up. I agree that Repartitioned would be a useful > >>> addition. I'm wondering if it might also need to have > >>> a withStreamPartitioner method/field, similar to Produced? I'm not sure > >>> how > >>> widely this feature is really used, but seems it should be available for > >>> repartition topics. > >>> > >>> On Wed, Jul 17, 2019 at 11:26 AM Levani Kokhreidze > >>> <levani.co...@gmail.com> > >>> wrote: > >>> > >>>> Hey Sophie, > >>>> > >>>> In both cases KStream#repartition and KStream#repartition(Repartitioned) > >>>> topic will be created and managed by Kafka Streams. > >>>> Idea of Repartitioned is to give user more control over the topic such as > >>>> num of partitions. > >>>> I feel like Repartitioned parameter is something that is missing in > >>>> current DSL design. > >>>> Essentially giving user control over parallelism by configuring num of > >>>> partitions for internal topics. > >>>> > >>>> Hope this answers your question. > >>>> > >>>> Regards, > >>>> Levani > >>>> > >>>>> On Jul 17, 2019, at 9:02 PM, Sophie Blee-Goldman <sop...@confluent.io> > >>>> wrote: > >>>>> > >>>>> Hey Levani, > >>>>> > >>>>> Thanks for the KIP! Can you clarify one thing for me -- for the > >>>>> KStream#repartition signature taking a Repartitioned, will the topic be > >>>>> auto-created by Streams (which seems to be the case for the signature > >>>>> without a Repartitioned) or does it have to be pre-created? The wording > >>>> in > >>>>> the KIP makes it seem like one version of the method will auto-create > >>>>> topics while the other will not. > >>>>> > >>>>> Cheers, > >>>>> Sophie > >>>>> > >>>>> On Wed, Jul 17, 2019 at 10:15 AM Levani Kokhreidze < > >>>> levani.co...@gmail.com> > >>>>> wrote: > >>>>> > >>>>>> Hello, > >>>>>> > >>>>>> One more bump about KIP-221 ( > >>>>>> > >>>> https://cwiki.apache.org/confluence/display/KAFKA/KIP-221%3A+Enhance+KStream+with+Connecting+Topic+Creation+and+Repartition+Hint > >>>>>> < > >>>>>> > >>>> https://cwiki.apache.org/confluence/display/KAFKA/KIP-221:+Enhance+KStream+with+Connecting+Topic+Creation+and+Repartition+Hint > >>>>> ) > >>>>>> so it doesn’t get lost in mailing list :) > >>>>>> Would love to hear communities opinions/concerns about this KIP. > >>>>>> > >>>>>> Regards, > >>>>>> Levani > >>>>>> > >>>>>> > >>>>>>> On Jul 12, 2019, at 5:27 PM, Levani Kokhreidze <levani.co...@gmail.com > >>>>> > >>>>>> wrote: > >>>>>>> > >>>>>>> Hello, > >>>>>>> > >>>>>>> Kind reminder about this KIP: > >>>>>> > >>>> https://cwiki.apache.org/confluence/display/KAFKA/KIP-221%3A+Enhance+KStream+with+Connecting+Topic+Creation+and+Repartition+Hint > >>>>>> < > >>>>>> > >>>> https://cwiki.apache.org/confluence/display/KAFKA/KIP-221:+Enhance+KStream+with+Connecting+Topic+Creation+and+Repartition+Hint > >>>>>>> > >>>>>>> > >>>>>>> Regards, > >>>>>>> Levani > >>>>>>> > >>>>>>>> On Jul 9, 2019, at 11:38 AM, Levani Kokhreidze < > >>>> levani.co...@gmail.com > >>>>>> <mailto:levani.co...@gmail.com>> wrote: > >>>>>>>> > >>>>>>>> Hello, > >>>>>>>> > >>>>>>>> In order to move this KIP forward, I’ve updated confluence page with > >>>>>> the new proposal > >>>>>> > >>>> https://cwiki.apache.org/confluence/display/KAFKA/KIP-221%3A+Enhance+KStream+with+Connecting+Topic+Creation+and+Repartition+Hint > >>>>>> < > >>>>>> > >>>> https://cwiki.apache.org/confluence/display/KAFKA/KIP-221:+Enhance+KStream+with+Connecting+Topic+Creation+and+Repartition+Hint > >>>>>>> > >>>>>>>> I’ve also filled “Rejected Alternatives” section. > >>>>>>>> > >>>>>>>> Looking forward to discuss this KIP :) > >>>>>>>> > >>>>>>>> King regards, > >>>>>>>> Levani > >>>>>>>> > >>>>>>>> > >>>>>>>>> On Jul 3, 2019, at 1:08 PM, Levani Kokhreidze < > >>>> levani.co...@gmail.com > >>>>>> <mailto:levani.co...@gmail.com>> wrote: > >>>>>>>>> > >>>>>>>>> Hello Matthias, > >>>>>>>>> > >>>>>>>>> Thanks for the feedback and ideas. > >>>>>>>>> I like the idea of introducing dedicated `Topic` class for topic > >>>>>> configuration for internal operators like `groupedBy`. > >>>>>>>>> Would be great to hear others opinion about this as well. > >>>>>>>>> > >>>>>>>>> Kind regards, > >>>>>>>>> Levani > >>>>>>>>> > >>>>>>>>> > >>>>>>>>>> On Jul 3, 2019, at 7:00 AM, Matthias J. Sax <matth...@confluent.io > >>>>>> <mailto:matth...@confluent.io>> wrote: > >>>>>>>>>> > >>>>>>>>>> Levani, > >>>>>>>>>> > >>>>>>>>>> Thanks for picking up this KIP! And thanks for summarizing > >>>> everything. > >>>>>>>>>> Even if some points may have been discussed already (can't really > >>>>>>>>>> remember), it's helpful to get a good summary to refresh the > >>>>>> discussion. > >>>>>>>>>> > >>>>>>>>>> I think your reasoning makes sense. With regard to the distinction > >>>>>>>>>> between operators that manage topics and operators that use > >>>>>> user-created > >>>>>>>>>> topics: Following this argument, it might indicate that leaving > >>>>>>>>>> `through()` as-is (as an operator that uses use-defined topics) and > >>>>>>>>>> introducing a new `repartition()` operator (an operator that > >>>>>>>>>> manages > >>>>>>>>>> topics itself) might be good. Otherwise, there is one operator > >>>>>>>>>> `through()` that sometimes manages topics but sometimes not; a > >>>>>> different > >>>>>>>>>> name, ie, new operator would make the distinction clearer. > >>>>>>>>>> > >>>>>>>>>> About adding `numOfPartitions` to `Grouped`. I am wondering if the > >>>>>> same > >>>>>>>>>> argument as for `Produced` does apply and adding it is semantically > >>>>>>>>>> questionable? Might be good to get opinions of others on this, too. > >>>> I > >>>>>> am > >>>>>>>>>> not sure myself what solution I prefer atm. > >>>>>>>>>> > >>>>>>>>>> So far, KS uses configuration objects that allow to configure a > >>>>>> certain > >>>>>>>>>> "entity" like a consumer, producer, store. If we assume that a > >>>>>>>>>> topic > >>>>>> is > >>>>>>>>>> a similar entity, I am wonder if we should have a > >>>>>>>>>> `Topic#withNumberOfPartitions()` class and method instead of a > >>>>>>>>>> plain > >>>>>>>>>> integer? This would allow us to add other configs, like replication > >>>>>>>>>> factor, retention-time etc, easily, without the need to change the > >>>>>> "main > >>>>>>>>>> API". > >>>>>>>>>> > >>>>>>>>>> Just want to give some ideas. Not sure if I like them myself. :) > >>>>>>>>>> > >>>>>>>>>> > >>>>>>>>>> -Matthias > >>>>>>>>>> > >>>>>>>>>> > >>>>>>>>>> > >>>>>>>>>> On 7/1/19 1:04 AM, Levani Kokhreidze wrote: > >>>>>>>>>>> Actually, giving it more though - maybe enhancing Produced with > >>>>>>>>>>> num > >>>>>> of partitions configuration is not the best approach. Let me explain > >>>> why: > >>>>>>>>>>> > >>>>>>>>>>> 1) If we enhance Produced class with this configuration, this will > >>>>>> also affect KStream#to operation. Since KStream#to is the final sink of > >>>> the > >>>>>> topology, for me, it seems to be reasonable assumption that user needs > >>>> to > >>>>>> manually create sink topic in advance. And in that case, having num of > >>>>>> partitions configuration doesn’t make much sense. > >>>>>>>>>>> > >>>>>>>>>>> 2) Looking at Produced class, based on API contract, seems like > >>>>>> Produced is designed to be something that is explicitly for producer > >>>> (key > >>>>>> serializer, value serializer, partitioner those all are producer > >>>> specific > >>>>>> configurations) and num of partitions is topic level configuration. And > >>>> I > >>>>>> don’t think mixing topic and producer level configurations together in > >>>> one > >>>>>> class is the good approach. > >>>>>>>>>>> > >>>>>>>>>>> 3) Looking at KStream interface, seems like Produced parameter is > >>>>>> for operations that work with non-internal (e.g topics created and > >>>> managed > >>>>>> internally by Kafka Streams) topics and I think we should leave it as > >>>> it is > >>>>>> in that case. > >>>>>>>>>>> > >>>>>>>>>>> Taking all this things into account, I think we should distinguish > >>>>>> between DSL operations, where Kafka Streams should create and manage > >>>>>> internal topics (KStream#groupBy) vs topics that should be created in > >>>>>> advance (e.g KStream#to). > >>>>>>>>>>> > >>>>>>>>>>> To sum it up, I think adding numPartitions configuration in > >>>> Produced > >>>>>> will result in mixing topic and producer level configuration in one > >>>> class > >>>>>> and it’s gonna break existing API semantics. > >>>>>>>>>>> > >>>>>>>>>>> Regarding making topic name optional in KStream#through - I think > >>>>>> underline idea is very useful and giving users possibility to specify > >>>> num > >>>>>> of partitions there is even more useful :) Considering arguments > >>>>>> against > >>>>>> adding num of partitions in Produced class, I see two options here: > >>>>>>>>>>> 1) Add following method overloads > >>>>>>>>>>> * through() - topic will be auto-generated and num of partitions > >>>>>> will be taken from source topic > >>>>>>>>>>> * through(final int numOfPartitions) - topic will be auto > >>>>>> generated with specified num of partitions > >>>>>>>>>>> * through(final int numOfPartitions, final Produced<K, V> > >>>>>> produced) - topic will be with generated with specified num of > >>>> partitions > >>>>>> and configuration taken from produced parameter. > >>>>>>>>>>> 2) Leave KStream#through as it is and introduce new method - > >>>>>> KStream#repartition (I think Matthias suggested this in one of the > >>>> threads) > >>>>>>>>>>> > >>>>>>>>>>> Considering all mentioned above I propose the following plan: > >>>>>>>>>>> > >>>>>>>>>>> Option A: > >>>>>>>>>>> 1) Leave Produced as it is > >>>>>>>>>>> 2) Add num of partitions configuration to Grouped class (as > >>>>>> mentioned in the KIP) > >>>>>>>>>>> 3) Add following method overloads to KStream#through > >>>>>>>>>>> * through() - topic will be auto-generated and num of partitions > >>>>>> will be taken from source topic > >>>>>>>>>>> * through(final int numOfPartitions) - topic will be auto > >>>>>> generated with specified num of partitions > >>>>>>>>>>> * through(final int numOfPartitions, final Produced<K, V> > >>>>>> produced) - topic will be with generated with specified num of > >>>> partitions > >>>>>> and configuration taken from produced parameter. > >>>>>>>>>>> > >>>>>>>>>>> Option B: > >>>>>>>>>>> 1) Leave Produced as it is > >>>>>>>>>>> 2) Add num of partitions configuration to Grouped class (as > >>>>>> mentioned in the KIP) > >>>>>>>>>>> 3) Add new operator KStream#repartition for creating and managing > >>>>>> internal repartition topics > >>>>>>>>>>> > >>>>>>>>>>> P.S. I’m sorry if all of this was already discussed in the mailing > >>>>>> list, but I kinda got with all the threads that were about this KIP :( > >>>>>>>>>>> > >>>>>>>>>>> Kind regards, > >>>>>>>>>>> Levani > >>>>>>>>>>> > >>>>>>>>>>>> On Jul 1, 2019, at 9:56 AM, Levani Kokhreidze < > >>>>>> levani.co...@gmail.com <mailto:levani.co...@gmail.com>> wrote: > >>>>>>>>>>>> > >>>>>>>>>>>> Hello, > >>>>>>>>>>>> > >>>>>>>>>>>> I would like to resurrect discussion around KIP-221. Going > >>>>>>>>>>>> through > >>>>>> the discussion thread, there’s seems to agreement around usefulness of > >>>> this > >>>>>> feature. > >>>>>>>>>>>> Regarding the implementation, as far as I understood, the most > >>>>>> optimal solution for me seems the following: > >>>>>>>>>>>> > >>>>>>>>>>>> 1) Add two method overloads to KStream#through method > >>>>>>>>>>>> (essentially > >>>>>> making topic name optional) > >>>>>>>>>>>> 2) Enhance Produced class with numOfPartitions configuration > >>>> field. > >>>>>>>>>>>> > >>>>>>>>>>>> Those two changes will allow DSL users to control parallelism and > >>>>>> trigger re-partition without doing stateful operations. > >>>>>>>>>>>> > >>>>>>>>>>>> I will update KIP with interface changes around KStream#through > >>>>>>>>>>>> if > >>>>>> this changes sound sensible. > >>>>>>>>>>>> > >>>>>>>>>>>> Kind regards, > >>>>>>>>>>>> Levani > >>>>>>>>>>> > >>>>>>>>>>> > >>>>>>>>>> > >>>>>>>>> > >>>>>>>> > >>>>>>> > >>>>>> > >>>>>> > >>>> > >>>> > >> >
