[GitHub] [arrow-datafusion] Dandandan commented on a change in pull request #569: Use repartition in window functions to speed up

[GitBox <gi...@apache.org>]

Dandandan commented on a change in pull request #569:
URL: https://github.com/apache/arrow-datafusion/pull/569#discussion_r656508927



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File path: datafusion/src/physical_plan/windows.rs
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@@ -412,11 +412,14 @@ impl ExecutionPlan for WindowAggExec {
 
     /// Get the output partitioning of this plan
     fn output_partitioning(&self) -> Partitioning {
-        Partitioning::UnknownPartitioning(1)
+        // because we can have repartitioning using the partition keys
+        // this would be either 1 or more than 1 depending on the presense of
+        // repartitioning
+        self.input.output_partitioning()
     }
 
     fn required_child_distribution(&self) -> Distribution {
-        Distribution::SinglePartition
+        Distribution::UnspecifiedDistribution

Review comment:
       Would this be correct with a window without any `partition by` clause?
   
   In that case I think the required partitions should be 1, as the aggregate function can not be computed only over a part of the data.




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