diff --git a/src/gausskernel/dbmind/kernel/index_advisor.cpp b/src/gausskernel/dbmind/kernel/index_advisor.cpp
index 61f9d5659..6e09ce67d 100644
--- a/src/gausskernel/dbmind/kernel/index_advisor.cpp
+++ b/src/gausskernel/dbmind/kernel/index_advisor.cpp
@@ -1011,9 +1011,10 @@ void parse_field_expr(List *field, List *op, List *lfield_values)
         index->index_name = index_name;
         index->cardinality = cardinality;
         index->op = op_type;
-        index->field_expr = field_expr.data;
+        index->field_expr = pstrdup(field_expr.data);
         add_index_from_field(table_name, index);
     }
+    pfree_ext(field_expr.data);
 }
 
 inline uint4 tuple_to_uint(List *tuples)