diff --git a/datafusion/physical-plan/src/aggregates/mod.rs b/datafusion/physical-plan/src/aggregates/mod.rs
index 921de96252f0..f779322456ca 100644
--- a/datafusion/physical-plan/src/aggregates/mod.rs
+++ b/datafusion/physical-plan/src/aggregates/mod.rs
@@ -101,34 +101,6 @@ impl AggregateMode {
     }
 }
 
-/// Group By expression modes
-///
-/// `PartiallyOrdered` and `FullyOrdered` are used to reason about
-/// when certain group by keys will never again be seen (and thus can
-/// be emitted by the grouping operator).
-///
-/// Specifically, each distinct combination of the relevant columns
-/// are contiguous in the input, and once a new combination is seen
-/// previous combinations are guaranteed never to appear again
-#[derive(Debug, Clone, Copy, PartialEq, Eq)]
-pub enum GroupByOrderMode {
-    /// The input is known to be ordered by a preset (prefix but
-    /// possibly reordered) of the expressions in the `GROUP BY` clause.
-    ///
-    /// For example, if the input is ordered by `a, b, c` and we group
-    /// by `b, a, d`, `PartiallyOrdered` means a subset of group `b,
-    /// a, d` defines a preset for the existing ordering, in this case
-    /// `a, b`.
-    PartiallyOrdered,
-    /// The input is known to be ordered by *all* the expressions in the
-    /// `GROUP BY` clause.
-    ///
-    /// For example, if the input is ordered by `a, b, c, d` and we group by b, a,
-    /// `Ordered` means that all of the of group by expressions appear
-    ///  as a preset for the existing ordering, in this case `a, b`.
-    FullyOrdered,
-}
-
 /// Represents `GROUP BY` clause in the plan (including the more general GROUPING SET)
 /// In the case of a simple `GROUP BY a, b` clause, this will contain the expression [a, b]
 /// and a single group [false, false].