Hi Eno,
Thank you. I don't think I'm advanced enough to imagine a good API. But I
can elaborate my use-cases further.
So say I have two tables:
KTable<String,String> left = topology.table(stringSerde,
stringSerde, topicLeft, topicLeft);
KTable<String,String> right = topology.table(stringSerde,
stringSerde, topicRight, topicRight);
left
.leftJoin(right, (l, r) -> asList(l, r))
.to(topicView)
- I'd like to filter duplicates out of the change stream. I only want
topicView to receive proper updates.
- I'd like to be able to detect change type easy:
- oldValue == null and newValue != null => create
- oldValue != null and newValue == null => delete
- oldValue != null and newValue != null => update
- I'd like to be able to update indices when records are deleted or
updated. Old values are needed to determine which index keys which should
be updated or removed.
I can do all these things now, mostly with groupBy()/reduce(),
groupBy/aggregate() and transform().
Best,
Dmitry
On Tue, Feb 21, 2017 at 5:21 PM, Eno Thereska <eno.there...@gmail.com>
wrote:
> Hi Dmitry,
>
> Could you tell us more on the exact API you'd like? Perhaps if others find
> it useful too we/you can do a KIP.
>
> Thanks
> Eno
>
> > On 21 Feb 2017, at 22:01, Dmitry Minkovsky <dminkov...@gmail.com> wrote:
> >
> > At KAFKA-2984: ktable sends old values when required
> > <https://github.com/apache/kafka/pull/672#issue-122101101>, @ymatsuda
> > writes:
> >
> >> NOTE: This is meant to be used by aggregation. But, if there is a use
> > case like a SQL database trigger, we can add a new KTable method to
> expose
> > this.
> >
> > Looking through the source it does not seem that this API was ever
> exposed.
> > Not finding anything on Google on this subject either. The SQL database
> > trigger is my exact use case. Enabling change-streaming for some tables
> > would help simplify my code. Is this possible? Is this scheduled for a
> > future version?
> >
> > Thank you,
> > Dmitry
>
>
