The OVER windows have been implemented by several contributors.
We should do a post pass over the contributed code and improve a few things.
- Currently every time attribute is allowed as ORDER BY attribute. We must check that this is actually a time indicator (procTime(), rowTime()) and that the order is ASCENDING.
- Add documentation for OVER windows
- Code style
- Consistent naming of ProcessFunctions and methods
- Move the OVER window tests out of SqlITCase into a dedicated class
- Move the OVER window tests out of WindowAggregateTest into a dedicated class
- Add tests based on the test harness for all ProcessFunctions similar to BoundedProcessingOverRangeProcessFunction. The tests should include exact boundary checks for range windows and check for proper parallelization with multiple keys.