Got it. Thanks John, this make sense. I've updated the KIP to include the deprecation of:
- KStream#transform - KStream#transformValues - KStream#flatTransform - KStream#flatTransformValues On Fri, 11 Feb 2022 at 15:16, John Roesler <vvcep...@apache.org> wrote: > Thanks, Jorge! > > I think it’ll be better to keep this KIP focused on KStream methods only. > I suspect that the KTable methods may be more complicated than just that > proposed replacement, but it’ll also be easier to consider that question in > isolation. > > The nice thing about just deprecating the KStream methods and not the > Transform* interfaces is that you can keep your proposal just scoped to > KStream and not have any consequences for the rest of the DSL. > > Thanks again, > John > > On Fri, Feb 11, 2022, at 06:43, Jorge Esteban Quilcate Otoya wrote: > > Thanks, John. > > > >> 4) I agree that we shouldn't deprecate the Transformer* > > classes, but do you think we should deprecate the > > KStream#transform* methods? I'm curious if there's any > > remaining reason to have those methods, or if your KIP > > completely obviates them. > > > > Good catch. > > I considered that deprecating `Transformer*` and `transform*` would go > hand > > in hand — maybe it happened similarly with old `Processor` and `process`? > > Though deprecating only `transform*` operations could be a better signal > > for users than non deprecating anything at all and pave the way to it's > > deprecation. > > > > Should this deprecation also consider including `KTable#transformValues`? > > The approach proposed on the KIP: > > `ktable.toStream().processValues().toTable()` seems fair to me, though I > > will have to test it further. > > > > I'm happy to update the KIP if there's some consensus around this. > > Will add the deprecation notes these days and wait for any additional > > feedback on this topic before wrapping up the KIP. > > > > > > On Fri, 11 Feb 2022 at 04:03, John Roesler <vvcep...@apache.org> wrote: > > > >> Thanks for the update, Jorge! > >> > >> I just read over the KIP again, and I'm in support. One more > >> question came up for me, though: > >> > >> 4) I agree that we shouldn't deprecate the Transformer* > >> classes, but do you think we should deprecate the > >> KStream#transform* methods? I'm curious if there's any > >> remaining reason to have those methods, or if your KIP > >> completely obviates them. > >> > >> Thanks, > >> -John > >> > >> On Thu, 2022-02-10 at 21:32 +0000, Jorge Esteban Quilcate > >> Otoya wrote: > >> > Thank you both for your feedback! > >> > > >> > I have added the following note on punctuation: > >> > > >> > ``` > >> > NOTE: The key validation can be defined when processing the message. > >> > Though, with punctuations it won't be possible to define the key for > >> > validation before forwarding, therefore it won't be possible to > forward > >> > from punctuation. > >> > This is similar behavior to how `ValueTransformer`s behave at the > moment. > >> > ``` > >> > > >> > Also make it explicit also that we are going to apply referencial > >> equality > >> > for key validation. > >> > > >> > I hope this is covering all your feedback, let me know if I'm missing > >> > anything. > >> > > >> > Cheers, > >> > Jorge. > >> > > >> > On Wed, 9 Feb 2022 at 22:19, Guozhang Wang <wangg...@gmail.com> > wrote: > >> > > >> > > I'm +1 on John's point 3) for punctuations. > >> > > > >> > > And I think if people are on the same page that a reference equality > >> check > >> > > per record is not a huge overhead, I think doing that enforcement is > >> better > >> > > than documentations and hand-wavy undefined behaviors. > >> > > > >> > > > >> > > Guozhang > >> > > > >> > > On Wed, Feb 9, 2022 at 11:27 AM John Roesler <vvcep...@apache.org> > >> wrote: > >> > > > >> > > > Thanks for the KIP Jorge, > >> > > > > >> > > > I'm in support of your proposal. > >> > > > > >> > > > 1) > >> > > > I do agree with Guozhang's point (1). I think the cleanest > >> > > > approach. I think it's cleaner and better to keep the > >> > > > enforcement internal to the framework than to introduce a > >> > > > public API or context wrapper for processors to use > >> > > > explicitly. > >> > > > > >> > > > 2) I tend to agree with you on this one; I think the > >> > > > equality check ought to be fast enough in practice. > >> > > > > >> > > > 3) I think this is implicit, but should be explicit in the > >> > > > KIP: For the `processValues` API, because the framework sets > >> > > > the key on the context before calling `process` and then > >> > > > unsets it afterwards, there will always be no key set during > >> > > > task puctuation. Therefore, while processors may still > >> > > > register punctuators, they will not be able to forward > >> > > > anything from them. > >> > > > > >> > > > This is functionally equivalent to the existing > >> > > > transformers, by the way, that are also forbidden to forward > >> > > > anything during punctuation. > >> > > > > >> > > > For what it's worth, I think this is the best tradeoff. > >> > > > > >> > > > The only alternative I see is not to place any restriction > >> > > > on forwarded keys at all and just document that if users > >> > > > don't maintain proper partitioning, they'll get undefined > >> > > > behavior. That might be more powerful, but it's also a > >> > > > usability problem. > >> > > > > >> > > > Thanks, > >> > > > -John > >> > > > > >> > > > On Wed, 2022-02-09 at 11:34 +0000, Jorge Esteban Quilcate > >> > > > Otoya wrote: > >> > > > > Thanks Guozhang. > >> > > > > > >> > > > > > Does `ValueProcessorContext` have to be a public API? It seems > >> to me > >> > > > > that this can be completely abstracted away from user interfaces > >> as an > >> > > > > internal class > >> > > > > > >> > > > > Totally agree. No intention to add these as public APIs. Will > >> update > >> > > the > >> > > > > KIP to reflect this. > >> > > > > > >> > > > > > in the past the rationale for enforcing it at the > >> > > > > interface layer rather than do runtime checks is that it is more > >> > > > efficient. > >> > > > > > I'm not sure how much overhead it may incur to check if the > key > >> did > >> > > not > >> > > > > change: if it is just a reference equality check maybe it's > okay. > >> > > What's > >> > > > > your take on this? > >> > > > > > >> > > > > Agree, reference equality should cover this validation and the > >> overhead > >> > > > > impact should not be meaningful. > >> > > > > Will update the KIP to reflect this as well. > >> > > > > > >> > > > > > >> > > > > On Tue, 8 Feb 2022 at 19:05, Guozhang Wang <wangg...@gmail.com> > >> wrote: > >> > > > > > >> > > > > > Hello Jorge, > >> > > > > > > >> > > > > > Thanks for bringing this KIP! I think this is a nice idea to > >> consider > >> > > > using > >> > > > > > a single overloaded function name for #process, just a couple > >> quick > >> > > > > > questions after reading the proposal: > >> > > > > > > >> > > > > > 1) Does `ValueProcessorContext` have to be a public API? It > >> seems to > >> > > me > >> > > > > > that this can be completely abstracted away from user > interfaces > >> as > >> > > an > >> > > > > > internal class, and we call the `setKey` before calling > >> > > > user-instantiated > >> > > > > > `process` function, and then in its overridden `forward` it > can > >> just > >> > > > check > >> > > > > > if the key changes or not. > >> > > > > > 2) Related to 1) above, in the past the rationale for > enforcing > >> it at > >> > > > the > >> > > > > > interface layer rather than do runtime checks is that it is > more > >> > > > efficient. > >> > > > > > I'm not sure how much overhead it may incur to check if the > key > >> did > >> > > not > >> > > > > > change: if it is just a reference equality check maybe it's > okay. > >> > > > What's > >> > > > > > your take on this? > >> > > > > > > >> > > > > > > >> > > > > > Guozhang > >> > > > > > > >> > > > > > On Tue, Feb 8, 2022 at 5:17 AM Jorge Esteban Quilcate Otoya < > >> > > > > > quilcate.jo...@gmail.com> wrote: > >> > > > > > > >> > > > > > > Hi Dev team, > >> > > > > > > > >> > > > > > > I'd like to start a new discussion thread on Kafka Streams > >> KIP-820: > >> > > > > > > > >> > > > > > > > >> > > > > > > >> > > > > >> > > > >> > https://cwiki.apache.org/confluence/display/KAFKA/KIP-820%3A+Extend+KStream+process+with+new+Processor+API > >> > > > > > > > >> > > > > > > This KIP is aimed to extend the current `KStream#process` > API > >> to > >> > > > return > >> > > > > > > output values that could be chained across the topology, as > >> well as > >> > > > > > > introducing a new `KStream#processValues` to use processor > >> while > >> > > > > > validating > >> > > > > > > keys haven't change and repartition is not required. > >> > > > > > > > >> > > > > > > Looking forward to your feedback. > >> > > > > > > > >> > > > > > > Regards, > >> > > > > > > Jorge. > >> > > > > > > > >> > > > > > > >> > > > > > > >> > > > > > -- > >> > > > > > -- Guozhang > >> > > > > > > >> > > > > >> > > > > >> > > > >> > > -- > >> > > -- Guozhang > >> > > > >> > >> >
