Hi John, Sorry for the confusion! I just noticed that we failed to document the merge operator. I've created https://issues.apache.org/jira/browse/KAFKA-7269 to fix it.
But in the mean time, * merge: interleave the records from two streams to produce one collated stream * join: compute a new stream by fusing together records from the two inputs by key For example: input-1: (A, 1) (B, 2) input-2: (A, 500) (C, 60) join( (l,r) -> new KeyValue(l, r) ): // simplified API (A, (1, 500) ) (B, (2, null) ) (C, (null, 60) ) merge: (A, 1) (A, 500) (B, 2) (C, 60) Does that make sense? -John Roesler On Thu, Aug 9, 2018 at 2:13 PM <jhel...@ups.com.invalid> wrote: > Hi All, > > > > I am a little confused on the difference between the > KStreamBuilder merge() function and doing a KStream-to-KStream Join > operation. I understand the difference between Inner, Left and Outer joins, > but I don't understand exactly what the difference is between the two. It > appears to me that both ways would merge two streams into a single stream, > but the joins do have the ability to remove duplicate data. Is that the > only difference? Also, on a side note, I am really clueless as to what the > difference between Windowed and Windowless means when referring to the > joins. > > > > Any help would be greatly appreciated. Thank you. > > > > John Heller > >
