diff --git a/proto/data.proto b/proto/data.proto
index 9bb15ebcc8d62..cdafd78f2f9a6 100644
--- a/proto/data.proto
+++ b/proto/data.proto
@@ -69,6 +69,10 @@ message DataType {
   repeated DataType field_type = 6;
   // Name of the fields if it is a struct type. For other types it will be empty.
   repeated string field_names = 7;
+  // Optional name of custom type.
+  // Informative-only and populated at best effort.
+  // NOT to be used for comparison or lookup.
+  optional string unqualified_name = 8;
 }
 
 message StructArrayData {
diff --git a/src/common/src/types/struct_type.rs b/src/common/src/types/struct_type.rs
index d649ca665df42..916b23ee4c0e0 100644
--- a/src/common/src/types/struct_type.rs
+++ b/src/common/src/types/struct_type.rs
@@ -35,7 +35,8 @@ impl Debug for StructType {
     }
 }
 
-#[derive(Debug, PartialEq, Eq, PartialOrd, Ord, Hash)]
+#[derive(Debug, educe::Educe)]
+#[educe(PartialEq, Eq, PartialOrd, Ord, Hash)]
 struct StructTypeInner {
     /// Details about a struct type. There are 2 cases for a struct:
     /// 1. `field_names.len() == field_types.len()`: it represents a struct with named fields,
@@ -44,6 +45,10 @@ struct StructTypeInner {
     ///     e.g. `ROW(1, 2)`.
     field_names: Box<[String]>,
     field_types: Box<[DataType]>,
+    #[educe(PartialEq(ignore))]
+    #[educe(Ord(ignore))]
+    #[educe(Hash(ignore))]
+    unqualified_name: Option<Box<str>>,
 }
 
 impl StructType {
@@ -59,6 +64,7 @@ impl StructType {
         Self(Arc::new(StructTypeInner {
             field_types: field_types.into(),
             field_names: field_names.into(),
+            unqualified_name: None,
         }))
     }
 
@@ -68,6 +74,7 @@ impl StructType {
         Self(Arc::new(StructTypeInner {
             field_types: Box::new([]),
             field_names: Box::new([]),
+            unqualified_name: None,
         }))
     }
 
@@ -76,6 +83,7 @@ impl StructType {
         Self(Arc::new(StructTypeInner {
             field_types: fields.into(),
             field_names: Box::new([]),
+            unqualified_name: None,
         }))
     }
 
@@ -164,6 +172,7 @@ impl FromStr for StructType {
         Ok(Self(Arc::new(StructTypeInner {
             field_types: field_types.into(),
             field_names: field_names.into(),
+            unqualified_name: None,
         })))
     }
 }
diff --git a/src/prost/src/lib.rs b/src/prost/src/lib.rs
index 0ebd4d5f4a096..617b517103ffc 100644
--- a/src/prost/src/lib.rs
+++ b/src/prost/src/lib.rs
@@ -410,6 +410,7 @@ impl std::fmt::Debug for data::DataType {
             type_name,
             // currently all data types are nullable
             is_nullable: _,
+            unqualified_name,
         } = self;
 
         let type_name = data::data_type::TypeName::try_from(*type_name)
@@ -417,6 +418,9 @@ impl std::fmt::Debug for data::DataType {
             .unwrap_or("Unknown");
 
         let mut s = f.debug_struct(type_name);
+        if let Some(unqualified_name) = unqualified_name {
+            s.field("unqualified_name", unqualified_name);
+        }
         if self.precision != 0 {
             s.field("precision", precision);
         }