fix: preserve field metadata from right side of union

apache · Oct 3, 2024 · 0a18ba4 · 0a18ba4
1 parent 31cbfbd
commit 0a18ba4
Show file tree

Hide file tree

Showing 2 changed files with 13 additions and 2 deletions.
diff --git a/datafusion/physical-plan/src/union.rs b/datafusion/physical-plan/src/union.rs
@@ -474,7 +474,12 @@ fn union_schema(inputs: &[Arc<dyn ExecutionPlan>]) -> SchemaRef {
                 .iter()
                 .filter_map(|input| {
                     if input.schema().fields().len() > i {
-                        Some(input.schema().field(i).clone())
+                        let field = input.schema().field(i).clone();
+                        let right_hand_metdata =
+                            inputs[1].schema().field(i).metadata().clone();
+                        let mut metadata = field.metadata().clone();
+                        metadata.extend(right_hand_metdata);
+                        Some(field.with_metadata(metadata))
                     } else {
                         None
                     }

diff --git a/datafusion/sqllogictest/test_files/metadata.slt b/datafusion/sqllogictest/test_files/metadata.slt
@@ -111,11 +111,17 @@ FROM
 6
 
 # Regression test: missing field metadata, from the NULL field on the left side of the union
-statement error DataFusion error: Internal error: Physical input schema should be the same as the one converted from logical input schema..
+query ITT
 (SELECT id, NULL::string as name, l_name FROM "table_with_metadata")
   UNION
 (SELECT id, name, NULL::string as l_name FROM "table_with_metadata")
 ORDER BY id, name, l_name;
+----
+1 NULL NULL
+3 baz NULL
+3 NULL l_baz
+NULL bar NULL
+NULL NULL l_bar