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
