fix

fe/fe-core/src/main/java/org/apache/doris/nereids/cost/CostModelV1.java

@@ -227,7 +227,7 @@ public Cost visitPhysicalDistribute(
         }
 
         // any
-        // cost of randome shuffle is lower than hash shuffle.
+        // cost of random shuffle is lower than hash shuffle.
         return CostV1.of(
                 0,
                 0,

fe/fe-core/src/main/java/org/apache/doris/nereids/properties/ChildrenPropertiesRegulator.java

@@ -121,7 +121,6 @@ public Boolean visitPhysicalHashAggregate(PhysicalHashAggregate<? extends Plan>
         // no matter x.ndv is high or not, it is not worthwhile to shuffle A and B by x
         // and hence we forbid one phase agg
         if (agg.getAggMode() == AggMode.INPUT_TO_RESULT
-                && requiredProperties.get(0).getDistributionSpec() instanceof DistributionSpecHash
                 && children.get(0).getPlan() instanceof PhysicalUnion
                 && !((PhysicalUnion) children.get(0).getPlan()).isDistinct()) {
             return false;

regression-test/suites/nereids_p0/aggregate/agg_union_random.groovy

@@ -0,0 +1,54 @@
+/*
+ * Licensed to the Apache Software Foundation (ASF) under one
+ * or more contributor license agreements.  See the NOTICE file
+ * distributed with this work for additional information
+ * regarding copyright ownership.  The ASF licenses this file
+ * to you under the Apache License, Version 2.0 (the
+ * "License"); you may not use this file except in compliance
+ * with the License.  You may obtain a copy of the License at
+ *
+ *  http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing,
+ * software distributed under the License is distributed on an
+ * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
+ * KIND, either express or implied.  See the License for the
+ * specific language governing permissions and limitations
+ * under the License.
+ */
+
+suite("agg_union_random") {
+    sql "SET enable_nereids_planner=true"
+    sql "SET enable_fallback_to_original_planner=false"
+    sql "DROP TABLE IF EXISTS test_random;"
+    sql """
+        create table test_random
+        (
+            a varchar(100) null,
+            b decimalv3(18,10) null
+        ) ENGINE=OLAP
+        DUPLICATE KEY(`a`)
+        DISTRIBUTED BY HASH(`a`) BUCKETS 1
+        PROPERTIES (
+        "replication_allocation" = "tag.location.default: 1"
+        );
+    """
+
+    explain{
+        sql "select a from (select * from test_random union all (select * from test_random))t group by a"
+            /**
+            STREAM DATA SINK
+                EXCHANGE ID: 258
+                RANDOM
+
+            252:VOlapScanNode
+                TABLE: default_cluster:regression_test_nereids_p0_aggregate.test_random(test_random), PREAGGREGATION: ON
+                partitions=0/1, tablets=0/0, tabletList=
+                cardinality=1, avgRowSize=0.0, numNodes=1
+                pushAggOp=NONE
+            **/
+        contains "RANDOM"
+    }
+
+    sql "DROP TABLE IF EXISTS test_random;"
+}