Hi Sophie, Seems I do have some mis-understanding of the KIP's motivation here :) Just for clarification my reasoning is that:
1) today Streams itself never uses a windowed deserializer itself since its built-in operators only need the serializer and users do not need to override it, plus standby / restore active tasks would just copy the bytes directly. So this KIP's motivation is not for Stream's own code anyways. 2) It is only when user specified serde is missing the window size, which is either when a) one is trying to read a source topic as windowed records in Streams, this is a big blocker for KIP-300, and when b) one is trying to read a topic as windowed records in Consumer, we would have issues if users fail to use the appropriate serde constructs. I thought the main motivation of this KIP is for 2.a), in which we would just encourage the users to use the right constructor with the window size by deprecating the other constructs. But I'm not sure how this would help with 2.b) since the proposal is on adding to StreamsConfig. If it is the case, then I agree that probably we can just not add an extra config but just deprecating the constructs. Guozhang On Tue, Sep 8, 2020 at 10:50 AM Sophie Blee-Goldman <sop...@confluent.io> wrote: > Hey Guozhang & Leah, > > I want to push back a bit on the assumption that we would fall back on this > config > in the case of an unspecified window size in a Streams serde. I don't think > it should > be a default at all, either in name or in effect. To borrow the rhetorical > question that > John raised earlier: what is the default window size of an application? > > Personally, I agree that that doesn't make much sense. Sure, if you only > have a single > windowed operation in your app then you could just specify the window size > by config, > but how is that any more ergonomic than specifying the window size in the > Serde's > constructor? If anything, it seems worse to put physical and mental > distance between > the specification and the actual usage of such parameters. What if you add > another > windowed operation later, with a different size, and forget to specify the > new size in > the new Serde? Or what if you never specify a default window size config at > all and > accidentally end up using the default config value of Long.MAX_VALUE? > Avoiding this > possibility was/is one of the main motivations of this KIP, and the whole > point of > deprecating the TimeWindowedSerde(innerClass) constructor. > > I actually would have advocated to remove this config entirely, but as John > pointed > out, we still need it to configure things like the console consumer > > On Tue, Sep 8, 2020 at 10:40 AM Leah Thomas <ltho...@confluent.io> wrote: > > > Hi Guozhang, > > > > Yes, the config would read them as a single window size. I think this > > relates to John's comments about having variably sized windows, which > this > > config doesn't handle. I like the name change and updated the wiki to > > reflect that, and to clarify that the default value will still be > > Long.MAX_VALUE. > > > > Thanks for your feedback! > > Leah > > > > On Tue, Sep 8, 2020 at 11:54 AM Guozhang Wang <wangg...@gmail.com> > wrote: > > > > > Hello Leah, > > > > > > Thanks for initiating this. I just have one minor clarification > question > > > here: the config "window.size.ms" seems to be used as the default > window > > > size when reading from a topic that represents windowed records right? > > I.e. > > > if there are multiple topics that represent windowed records but their > > > window sizes are different, with this config we can only read them > with a > > > single window size? If yes, could we rename the config as " > > > default.window.size.ms" and make that clear in the description as > well? > > > Also we'd better also include its default value which I think would > still > > > be MAX_VALUE for compatibility. > > > > > > > > > Guozhang > > > > > > > > > On Tue, Sep 8, 2020 at 9:38 AM Leah Thomas <ltho...@confluent.io> > wrote: > > > > > > > Hey all, > > > > > > > > We should be good to wrap up voting now that the discussion has been > > > > resolved. > > > > > > > > Cheers, > > > > Leah > > > > > > > > On Wed, Sep 2, 2020 at 7:23 PM Matthias J. Sax <mj...@apache.org> > > wrote: > > > > > > > > > +1 (binding) > > > > > > > > > > On 8/26/20 8:02 AM, John Roesler wrote: > > > > > > Hi all, > > > > > > > > > > > > I've just sent a new message to the DISCUSS thread. We > > > > > > forgot to include the Scala API in the proposal. > > > > > > > > > > > > Thanks, > > > > > > -John > > > > > > > > > > > > On Mon, 2020-08-24 at 18:00 -0700, Sophie Blee-Goldman > > > > > > wrote: > > > > > >> Thanks for the KIP! +1 (non-binding) > > > > > >> > > > > > >> Sophie > > > > > >> > > > > > >> On Mon, Aug 24, 2020 at 5:06 PM John Roesler < > vvcep...@apache.org > > > > > > > > wrote: > > > > > >> > > > > > >>> Thanks Leah, > > > > > >>> I’m +1 (binding) > > > > > >>> > > > > > >>> -John > > > > > >>> > > > > > >>> On Mon, Aug 24, 2020, at 16:54, Leah Thomas wrote: > > > > > >>>> Hi everyone, > > > > > >>>> > > > > > >>>> I'd like to kick-off the vote for KIP-659: Improve > > > > > >>>> TimeWindowedDeserializer > > > > > >>>> and TimeWindowedSerde to handle window size. > > > > > >>>> > > > > > >>> > > > > > > > > > > > > > > > https://cwiki.apache.org/confluence/display/KAFKA/KIP-659%3A+Improve+TimeWindowedDeserializer+and+TimeWindowedSerde+to+handle+window+size > > > > > >>>> Thanks, > > > > > >>>> Leah > > > > > >>>> > > > > > > > > > > > > > > > > > > > > > > > > > > > > > -- > > > -- Guozhang > > > > > > -- -- Guozhang
