mustafasrepo opened a new pull request, #6665:
URL: https://github.com/apache/arrow-datafusion/pull/6665
# Which issue does this PR close?
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Closes #.
# Rationale for this change
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# What changes are included in this PR?
This PR implements the proposal in the
[#PR12](https://github.com/alamb/arrow-datafusion/pull/12)
- `evaluate_stateful` and `evaluate_inside_range` are combined under single
`evaluate` methods
- `uses_window_frame` and `supports_bounded_execution` methods are moved
from `BoundedWindowFunctionExpr` to `PartitionEvaluator`.
With the changes in this PR new Evaluators can be implemented according to
table below.
|uses_window_frame|supports_bounded_execution|function_to_implement|
|---|---|----|
|false|false|`evaluate_all` (if we were to implement `PERCENT_RANK` it would
end up in this quadrant, we cannot produce any result without seeing whole
data)|
|false|true|`evaluate` (optionally can also implement `evaluate_all` for
more optimized implementation. However, there will be default implementation
that is suboptimal) . If we were to implement `ROW_NUMBER` it will end up in
this quadrant. Example `OddRowNumber` showcases this use case|
|true|false|`evaluate` (I think as long as `uses_window_frame` is `true`.
There is no way for `supports_bounded_execution` to be false). I couldn't come
up with any example for this quadrant |
|true|true|`evaluate`. If we were to implement `FIRST_VALUE`, it would end
up in this quadrant|.
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# Are there any user-facing changes?
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