The goal of this issue is to add support for OVER ROW aggregations on processing time streams to the SQL interface.
Queries similar to the following should be supported:
The following restrictions should initially apply:
- All OVER clauses in the same SELECT clause must be exactly the same.
- The PARTITION BY clause is optional (no partitioning results in single threaded execution).
- The ORDER BY clause may only have procTime() as parameter. procTime() is a parameterless scalar function that just indicates processing time mode.
- x PRECEDING is not supported (see
- FOLLOWING is not supported.
The restrictions will be resolved in follow up issues. If we find that some of the restrictions are trivial to address, we can add the functionality in this issue as well.
This issue includes:
- Design of the DataStream operator to compute OVER ROW aggregates
- Translation from Calcite's RelNode representation (LogicalProject with RexOver expression).