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 <[email protected]> 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 >
