Hi Danny, seems like the "Red" syntax is missing? I am guessing you were talking about "L.window_start = R.window_start AND L.window_end = R.window_end"? Can you use ** to indicate the red part.
Two additional questions: > The Join action is triggered by the watermark of the stream So sounds like the you define the default as "trigger when window close" (i.e. watermark passes end of window) > The join does not produce retractions of the stream, the mainly difference with normal two-stream join Is this a limitation for "triggered by the watermark of the stream"? -Rui On Tue, Sep 22, 2020 at 9:42 PM James Starr <jamesst...@gmail.com> wrote: > Sorry, but what part is red. Your markup appears to have been stripped. > > James > > On Tue, Sep 22, 2020 at 9:05 PM Danny Chan <yuzhao....@gmail.com> wrote: > > > Hi, fellows, long time no see on the mailing ~ > > > > Here I want to have a discussion on the join syntax of our recently > > introduced window table function ~ > > > > For example, we can define a tumbling window function of 5 minutes size > as: > > > > Tumble(table T, descriptor(T.ts), INTERVAL ‘5’ MINUTE) > > > > The we can select from it, and moreover, I want to support 2 window > > function join for the streaming query recently. > > > > The semantics of the windowed stream join is: > > > > • The 2 window inputs should have the same window arguments (except for > > the table name), e.g. for TUMBLE the size should be equal, for HOP, both > > the side interval and size should be equal > > • We first window the input stream then join the both window data set of > > the same TimeWindow > > • The Join action is triggered by the watermark of the stream > > • The join does not produce retractions of the stream, the mainly > > difference with normal two-stream join > > > > And I want to propose a join syntax as: > > > > Select L.f0, R.f2, L.window_start, L.window_end > > FROM > > Tumble(table T1, descriptor(T1.ts), INTERVAL ‘5’ MINUTE) L > > JOIN > > Tumble(table T2, descriptor(T2.ts), INTERVAL ‘5’ MINUTE) R > > ON > > L.f0 = R.f0 AND L.window_start = R.window_start AND L.window_end = > > R.window_end > > > > The red syntax part is what I want to discuss, the condition seems too > > verbose because > > user need to declare it every time. > > > > > > • Should we make it optional ? > > • Is there better syntax to describe this window join semantics ? > > > > > > Best, > > Danny Chan > > >
