UNION to UNION ALL for efficiency (#226)

vega · Jan 16, 2023 · cd0eca3 · cd0eca3
1 parent f798f74
commit cd0eca3
Showing 1 changed file with 1 addition and 1 deletion.
diff --git a/vegafusion-rt-datafusion/src/transform/fold.rs b/vegafusion-rt-datafusion/src/transform/fold.rs
@@ -91,7 +91,7 @@ impl TransformTrait for Fold {
             })
             .collect::<Result<Vec<_>>>()?;
 
-        let union_subquery = subqueries.join(" UNION ");
+        let union_subquery = subqueries.join(" UNION ALL ");
         let union_subquery_name = "_union";
 
         let mut selections = input_selection.clone();