Hi, Julian, Great! I am looking forward to it. Could you help to answer my question regarding to the sliding windows in the previous email?
Thanks a lot! -Yi On Tue, May 5, 2015 at 10:46 AM, Julian Hyde <jul...@hydromatic.net> wrote: > > On May 4, 2015, at 10:52 AM, Yi Pan <nickpa...@gmail.com> wrote: > > > Just one observation that I wanted to add in: I noted that actually any > > range-based query clause on an ordered stream essentially means the need > > for a windowing method in the ordered stream scan. Is it possible to > > identify a common syntax expression from the query parser in Calcite for > > any range-based clauses on a StreamScan operator and extract the window > > spec like: > > LogicalProject(...) > > StreamScan(table=[[STREAMS, ORDERS]], fields=[[0,1,2,3]]) > > > > To: > > LogicalProject(...) > > LogicalWindow(<WindowSpec from the range defining expression in > > LogicalProject>) > > StreamScan(table=[[STREAMS, ORDERS]], fields=[[0,1,2,3]]) > > Yes, I plan to do this. > > Calcite treats LogicalWindow is a bit differently from the other logical > operators. A query that contains a windowed aggregate such as “SUM(units) > OVER <window>” is first translated to a LogicalProject that contains > windowed aggregates as if they were ordinary function calls, then > ProjectToWindowRule converts that LogicalProject to a LogicalWindow. > > But by the time Samza sees the relational expressions you can assume that > all windowed aggregates have been moved into a LogicalWindow. > > I have logged https://issues.apache.org/jira/browse/CALCITE-713. > > Julian > >
