[fix](Nereids) merge request properties map of group should compare c…

…ost (#40819)

pick from master #40819

when do merge, we should update target requestPropertiesMap ONLY IF the
cost of source's request property lower than target one. Otherwise, the
requestPropertiesMap will not sync with lowestCostTable. Then, we will
get wrong output property when get the final plan.

fe/fe-core/src/main/java/org/apache/doris/nereids/memo/GroupExpression.java

@@ -276,7 +276,27 @@ public void mergeToNotOwnerRemove(GroupExpression target) {
         this.getLowestCostTable()
                 .forEach((properties, pair) -> target.updateLowestCostTable(properties, pair.second, pair.first));
         // requestPropertiesMap
-        target.requestPropertiesMap.putAll(this.requestPropertiesMap);
+        // ATTN: when do merge, we should update target requestPropertiesMap
+        //   ONLY IF the cost of source's request property lower than target one.
+        //   Otherwise, the requestPropertiesMap will not sync with lowestCostTable.
+        //   Then, we will get wrong output property when get the final plan.
+        for (Map.Entry<PhysicalProperties, PhysicalProperties> entry : requestPropertiesMap.entrySet()) {
+            PhysicalProperties request = entry.getKey();
+            if (!target.requestPropertiesMap.containsKey(request)) {
+                target.requestPropertiesMap.put(entry.getKey(), entry.getValue());
+            } else {
+                PhysicalProperties sourceOutput = entry.getValue();
+                PhysicalProperties targetOutput = target.getRequestPropertiesMap().get(request);
+                if (this.getLowestCostTable().containsKey(sourceOutput)
+                        && target.getLowestCostTable().containsKey(targetOutput)) {
+                    Cost sourceCost = this.getLowestCostTable().get(sourceOutput).first;
+                    Cost targetCost = target.getLowestCostTable().get(targetOutput).first;
+                    if (sourceCost.getValue() < targetCost.getValue()) {
+                        target.requestPropertiesMap.put(entry.getKey(), entry.getValue());
+                    }
+                }
+            }
+        }
         // ruleMasks
         target.ruleMasks.or(this.ruleMasks);
 

fe/fe-core/src/test/java/org/apache/doris/nereids/memo/GroupExpressionTest.java

@@ -0,0 +1,61 @@
+// 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.
+
+package org.apache.doris.nereids.memo;
+
+import org.apache.doris.nereids.cost.Cost;
+import org.apache.doris.nereids.properties.PhysicalProperties;
+import org.apache.doris.nereids.trees.plans.FakePlan;
+
+import com.google.common.collect.Lists;
+import org.junit.jupiter.api.Assertions;
+import org.junit.jupiter.api.Test;
+
+public class GroupExpressionTest {
+
+    @Test
+    public void testMergeToNotOwnerRemoveWhenTargetWithLowerCost() {
+        GroupExpression source = new GroupExpression(new FakePlan());
+        source.updateLowestCostTable(PhysicalProperties.GATHER, Lists.newArrayList(), Cost.infinite());
+        source.putOutputPropertiesMap(PhysicalProperties.GATHER, PhysicalProperties.ANY);
+
+        GroupExpression target = new GroupExpression(new FakePlan());
+        target.updateLowestCostTable(PhysicalProperties.ANY, Lists.newArrayList(), Cost.zero());
+        target.putOutputPropertiesMap(PhysicalProperties.ANY, PhysicalProperties.ANY);
+
+        source.mergeToNotOwnerRemove(target);
+        Assertions.assertTrue(target.getLowestCostTable().containsKey(PhysicalProperties.ANY));
+        Assertions.assertTrue(target.getLowestCostTable().containsKey(PhysicalProperties.GATHER));
+        Assertions.assertEquals(PhysicalProperties.ANY, target.getOutputProperties(PhysicalProperties.ANY));
+    }
+
+    @Test
+    public void testMergeToNotOwnerRemoveWhenSourceWithLowerCost() {
+        GroupExpression source = new GroupExpression(new FakePlan());
+        source.updateLowestCostTable(PhysicalProperties.GATHER, Lists.newArrayList(), Cost.zero());
+        source.putOutputPropertiesMap(PhysicalProperties.GATHER, PhysicalProperties.ANY);
+
+        GroupExpression target = new GroupExpression(new FakePlan());
+        target.updateLowestCostTable(PhysicalProperties.ANY, Lists.newArrayList(), Cost.infinite());
+        target.putOutputPropertiesMap(PhysicalProperties.ANY, PhysicalProperties.ANY);
+
+        source.mergeToNotOwnerRemove(target);
+        Assertions.assertTrue(target.getLowestCostTable().containsKey(PhysicalProperties.ANY));
+        Assertions.assertTrue(target.getLowestCostTable().containsKey(PhysicalProperties.GATHER));
+        Assertions.assertEquals(PhysicalProperties.GATHER, target.getOutputProperties(PhysicalProperties.ANY));
+    }
+}