Dandandan commented on a change in pull request #9806:
URL: https://github.com/apache/arrow/pull/9806#discussion_r606779504



##########
File path: rust/datafusion/src/physical_plan/union.rs
##########
@@ -60,15 +60,31 @@ impl ExecutionPlan for UnionExec {
 
     /// Output of the union is the combination of all output partitions of the 
inputs
     fn output_partitioning(&self) -> Partitioning {
-        // Sums all the output partitions
-        let num_partitions = self
-            .inputs
+        let intial: Option<Partitioning> = None;
+        self.inputs
             .iter()
-            .map(|plan| plan.output_partitioning().partition_count())
-            .sum();
-        // TODO: this loses partitioning info in case of same partitioning 
scheme (for example `Partitioning::Hash`)
-        // https://issues.apache.org/jira/browse/ARROW-11991
-        Partitioning::UnknownPartitioning(num_partitions)
+            .fold(intial, |acc, input| {
+                match (acc, input.output_partitioning()) {
+                    (None, partition) => Some(partition),
+                    (
+                        Some(Partitioning::Hash(mut vector_acc, size_acc)),
+                        Partitioning::Hash(vector, size),
+                    ) => {
+                        vector_acc.append(&mut vector.clone());
+                        Some(Partitioning::Hash(vector_acc, size_acc + size))
+                    }
+                    (
+                        Some(Partitioning::RoundRobinBatch(size_acc)),
+                        Partitioning::RoundRobinBatch(size),
+                    ) => Some(Partitioning::RoundRobinBatch(size_acc + size)),

Review comment:
       `RoundRobinBatch(1000)` means  it still has 1000 partitions as output 
after repartitioning with round robin.




-- 
This is an automated message from the Apache Git Service.
To respond to the message, please log on to GitHub and use the
URL above to go to the specific comment.

For queries about this service, please contact Infrastructure at:
[email protected]


Reply via email to