tweaks

datafusion/physical-plan/src/aggregates/row_hash.rs

@@ -62,10 +62,12 @@ pub(crate) enum ExecutionState {
     /// When producing output, the remaining rows to output are stored
     /// here and are sliced off as needed in batch_size chunks
     ProducingOutput(RecordBatch),
-    /// Indicates that GroupedHashAggregateStream should produce
-    /// intermediate aggregate state for each input rows without
-    /// their aggregation
+    /// Produce intermediate aggregate state for each input row without
+    /// aggregation.
+    ///
+    /// See "partial aggregation" discussion on [`GroupedHashAggregateStream`]
     SkippingAggregation,
+    /// All input has been consumed and all groups have been emitted
     Done,
 }