Couple of follow up comment on the KIP: It seems that `windowSize` is a mandatory argument for windowed-tables, thus all overload should have the first two parameters being `String topic` and `Duration windowSize`.
For session-tables, there should be no `windowSize` parameter because each session can have a different size and as a matter of fact, both the window start and window end timestamp are contained in the key anyway for this reason. (This is different to time windows as the KIP mentions.) Thus, I don't think that there is any need to extend `Consumed` or `Materialized` -- in contrast, extending both as suggested would result in bad API, because those new methods would be available for key-value-tables, too. About generic types: why is `windowedTable()` using `Consumers<K,V>` while `sessionTable` is using `Consumed<Windowed<K,V>>`? The KIP mentions that we can wrap provided key-serdes automatically with corresponding window serdes. Thus, it seems the correct type should be `K`? -Matthias On 1/12/19 8:35 PM, Boyang Chen wrote: > Hey Matthias, > > thanks for taking a look! It would be great to see this pushed in 2.2. > Depending on the tight timeline, I hope to at least get the KIP approved so > that we don't see back and forth again as the KTable API has been constantly > changing. I couldn't guarantee the implementation timeline until we agree on > the updated high level APIs first. Does that make sense? > > Best, > Boyang > ________________________________ > From: Matthias J. Sax <matth...@confluent.io> > Sent: Sunday, January 13, 2019 10:53 AM > To: dev@kafka.apache.org > Subject: Re: [DISCUSS] KIP-300: Add Windowed KTable API in StreamsBuilder > > Do you want to get this into 2.2 release? KIP deadline is 1/24, so quite > soon. > > Overall, the KIP is very useful. I can review again in more details if > you aim for 2.2 -- did you address all previous comment about the KIP > already? > > > -Matthias > > > > On 1/8/19 2:50 PM, Boyang Chen wrote: >> Hey folks, >> >> I would like to start a discussion thread on adding new time/session >> windowed KTable APIs for KStream: >> https://cwiki.apache.org/confluence/display/KAFKA/KIP-300%3A+Add+Windowed+KTable+API+in+StreamsBuilder >> >> We have been working on this thread around 7 months ago, and it is >> successfully applied in our internal stream applications that enable >> data sharing across multiple jobs. As a matter of fact, materialization of >> windowed store is definitely a concrete use case that could unblock stream >> users to >> build more complex modules. >> >> Let me know if the API changes makes sense. >> >> Best, >> Boyang >> KIP-300: Add Windowed KTable API in StreamsBuilder - Apache Kafka - Apache >> Software >> Foundation<https://cwiki.apache.org/confluence/display/KAFKA/KIP-300%3A+Add+Windowed+KTable+API+in+StreamsBuilder> >> We have an existing table() API in the StreamsBuilder which could >> materialize a Kafka topic into a local state store called KTable. This >> interface is very useful when we want to back up a Kafka topic to local >> store. Sometimes we have certain requirement to materialize a windowed topic >> (or changlog ... >> cwiki.apache.org >> >> >> > >
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