Re: KStream: KTable-KTable leftJoin with key only on RHS of join generates null in joined table

Oh ok, I had assumed that distinguishing cases 1 and 2 was possible. Thanks. On 7 Jul 2016 1:02 p.m., "Guozhang Wang" wrote: > Hello, > > The problem is that, in stream processing when you have a new record coming > from the big table tB and does not find a match with the

Re: KStream: KTable-KTable leftJoin with key only on RHS of join generates null in joined table

Hello, The problem is that, in stream processing when you have a new record coming from the big table tB and does not find a match with the small table (i.e. only a sub set of keys in practice) in tA, you cannot tell which case of the following is true: 1. there was a matching record in tA,

Re: KStream: KTable-KTable leftJoin with key only on RHS of join generates null in joined table

thanks, I understand that it's not modelled the same way as database joins. Let's take an example of inner join of very small population set (NBA rookies or US senators) with larger table (data on zip codes). Let's assume we want to identify the crime rate of zip codes where current senators live

Re: KStream: KTable-KTable leftJoin with key only on RHS of join generates null in joined table

Hello, The KTable join semantics is not exactly the same with that of a RDBMS. You can fine detailed semantics in the web docs (search for Joining Streams): http://docs.confluent.io/3.0.0/streams/developer-guide.html#kafka-streams-dsl In a nutshell, the joiner will be triggered only if both /

Re: KStream: KTable-KTable leftJoin with key only on RHS of join generates null in joined table

Same happens for regular join, keys that appear only in one stream will make it to output KTable tC with a null for either input stream. I guess it's related to Kafka-3911 Enforce ktable Materialization or umbrella JIRA 3909, Queryable state for Kafka Streams? On Mon, Jul 4, 2016 at 8:45 PM,