diff --git a/iotdb-core/datanode/src/main/java/org/apache/iotdb/db/queryengine/plan/planner/plan/node/process/join/FullOuterTimeJoinNode.java b/iotdb-core/datanode/src/main/java/org/apache/iotdb/db/queryengine/plan/planner/plan/node/process/join/FullOuterTimeJoinNode.java
index f692e0867ff1..936be8f6a6e6 100644
--- a/iotdb-core/datanode/src/main/java/org/apache/iotdb/db/queryengine/plan/planner/plan/node/process/join/FullOuterTimeJoinNode.java
+++ b/iotdb-core/datanode/src/main/java/org/apache/iotdb/db/queryengine/plan/planner/plan/node/process/join/FullOuterTimeJoinNode.java
@@ -131,11 +131,30 @@ public boolean equals(Object o) {
     if (o == null || getClass() != o.getClass()) {
       return false;
     }
-    if (!super.equals(o)) {
+    // Don't call super.equals() to avoid order-sensitive children comparison
+    FullOuterTimeJoinNode that = (FullOuterTimeJoinNode) o;
+    // For FullOuterTimeJoinNode, the order of children doesn't matter semantically
+    // since all children are merged based on timestamps. Compare children as sets.
+    if (mergeOrder != that.mergeOrder
+        || !Objects.equals(this.getPlanNodeId(), that.getPlanNodeId())
+        || this.children.size() != that.children.size()) {
       return false;
     }
-    FullOuterTimeJoinNode that = (FullOuterTimeJoinNode) o;
-    return mergeOrder == that.mergeOrder;
+    // Compare children in an order-independent way by checking if each child in this
+    // has a corresponding equal child in that
+    for (PlanNode child : this.children) {
+      boolean found = false;
+      for (PlanNode thatChild : that.children) {
+        if (Objects.equals(child, thatChild)) {
+          found = true;
+          break;
+        }
+      }
+      if (!found) {
+        return false;
+      }
+    }
+    return true;
   }
 
   @Override
diff --git a/iotdb-core/datanode/src/test/java/org/apache/iotdb/db/queryengine/plan/optimization/ColumnInjectionPushDownTest.java b/iotdb-core/datanode/src/test/java/org/apache/iotdb/db/queryengine/plan/optimization/ColumnInjectionPushDownTest.java
index 06140fddafcf..e69a2d24a1ba 100644
--- a/iotdb-core/datanode/src/test/java/org/apache/iotdb/db/queryengine/plan/optimization/ColumnInjectionPushDownTest.java
+++ b/iotdb-core/datanode/src/test/java/org/apache/iotdb/db/queryengine/plan/optimization/ColumnInjectionPushDownTest.java
@@ -31,7 +31,6 @@
 
 import java.util.Arrays;
 import java.util.Collections;
-import java.util.HashMap;
 import java.util.LinkedHashMap;
 import java.util.List;
 import java.util.Map;
@@ -295,7 +294,7 @@ public void testPushDownAggregationSourceAlignByDevice() {
 
     List<String> outputColumnNames = Arrays.asList("Device", "__endTime", "count(s1)");
     List<String> devices = Arrays.asList("root.sg.d1", "root.sg.d2.a");
-    Map<String, List<Integer>> deviceToMeasurementIndexesMap = new HashMap<>();
+    Map<String, List<Integer>> deviceToMeasurementIndexesMap = new LinkedHashMap<>();
     deviceToMeasurementIndexesMap.put("root.sg.d1", Arrays.asList(1, 2));
     deviceToMeasurementIndexesMap.put("root.sg.d2.a", Arrays.asList(1, 2));
 
@@ -373,7 +372,7 @@ public void testPushDownSlidingWindowAlignByDevice() {
 
     List<String> outputColumnNames = Arrays.asList("Device", "__endTime", "count(s1)");
     List<String> devices = Arrays.asList("root.sg.d1", "root.sg.d2.a");
-    Map<String, List<Integer>> deviceToMeasurementIndexesMap = new HashMap<>();
+    Map<String, List<Integer>> deviceToMeasurementIndexesMap = new LinkedHashMap<>();
     deviceToMeasurementIndexesMap.put("root.sg.d1", Arrays.asList(1, 2));
     deviceToMeasurementIndexesMap.put("root.sg.d2.a", Arrays.asList(1, 2));
 
@@ -453,7 +452,7 @@ public void testPushDownRawDataAggregationAlignByDevice() {
 
     List<String> outputColumnNames = Arrays.asList("Device", "__endTime", "count(s1)");
     List<String> devices = Arrays.asList("root.sg.d1", "root.sg.d2.a");
-    Map<String, List<Integer>> deviceToMeasurementIndexesMap = new HashMap<>();
+    Map<String, List<Integer>> deviceToMeasurementIndexesMap = new LinkedHashMap<>();
     deviceToMeasurementIndexesMap.put("root.sg.d1", Arrays.asList(1, 2));
     deviceToMeasurementIndexesMap.put("root.sg.d2.a", Arrays.asList(1, 2));
 
diff --git a/iotdb-core/datanode/src/test/java/org/apache/iotdb/db/queryengine/plan/optimization/OptimizationTestUtil.java b/iotdb-core/datanode/src/test/java/org/apache/iotdb/db/queryengine/plan/optimization/OptimizationTestUtil.java
index b2e13e277741..e94145853040 100644
--- a/iotdb-core/datanode/src/test/java/org/apache/iotdb/db/queryengine/plan/optimization/OptimizationTestUtil.java
+++ b/iotdb-core/datanode/src/test/java/org/apache/iotdb/db/queryengine/plan/optimization/OptimizationTestUtil.java
@@ -44,7 +44,7 @@
 import java.time.ZonedDateTime;
 import java.util.Arrays;
 import java.util.Collections;
-import java.util.HashMap;
+import java.util.LinkedHashMap;
 import java.util.List;
 import java.util.Map;
 
@@ -54,7 +54,7 @@ private OptimizationTestUtil() {
     // util class
   }
 
-  public static final Map<String, PartialPath> schemaMap = new HashMap<>();
+  public static final Map<String, PartialPath> schemaMap = new LinkedHashMap<>();
 
   static {
     try {
@@ -159,6 +159,6 @@ public static AggregationDescriptor getAggregationDescriptor(AggregationStep ste
         TAggregationType.COUNT.name().toLowerCase(),
         step,
         Collections.singletonList(new TimeSeriesOperand(schemaMap.get(path))),
-        new HashMap<>());
+        new LinkedHashMap<>());
   }
 }
diff --git a/iotdb-core/datanode/src/test/java/org/apache/iotdb/db/queryengine/plan/optimization/TestPlanBuilder.java b/iotdb-core/datanode/src/test/java/org/apache/iotdb/db/queryengine/plan/optimization/TestPlanBuilder.java
index 9b25ae7787fe..7ad0bc49f66b 100644
--- a/iotdb-core/datanode/src/test/java/org/apache/iotdb/db/queryengine/plan/optimization/TestPlanBuilder.java
+++ b/iotdb-core/datanode/src/test/java/org/apache/iotdb/db/queryengine/plan/optimization/TestPlanBuilder.java
@@ -62,7 +62,7 @@
 import java.util.ArrayList;
 import java.util.Arrays;
 import java.util.Collections;
-import java.util.HashMap;
+import java.util.LinkedHashMap;
 import java.util.List;
 import java.util.Map;
 import java.util.stream.Collectors;
@@ -353,7 +353,7 @@ public TestPlanBuilder fill(String id, String intValue) {
 
   public TestPlanBuilder singleDeviceView(String id, String device, String measurement) {
     IDeviceID deviceID = IDeviceID.Factory.DEFAULT_FACTORY.create(device);
-    Map<IDeviceID, List<Integer>> deviceToMeasurementIndexesMap = new HashMap<>();
+    Map<IDeviceID, List<Integer>> deviceToMeasurementIndexesMap = new LinkedHashMap<>();
     deviceToMeasurementIndexesMap.put(deviceID, Collections.singletonList(1));
     DeviceViewNode deviceViewNode =
         new DeviceViewNode(
@@ -389,7 +389,7 @@ public TestPlanBuilder topK(
   public TestPlanBuilder singleOrderedDeviceView(
       String id, String device, OrderByParameter orderByParameter, String... measurement) {
     IDeviceID deviceID = IDeviceID.Factory.DEFAULT_FACTORY.create(device);
-    Map<IDeviceID, List<Integer>> deviceToMeasurementIndexesMap = new HashMap<>();
+    Map<IDeviceID, List<Integer>> deviceToMeasurementIndexesMap = new LinkedHashMap<>();
     deviceToMeasurementIndexesMap.put(
         deviceID, measurement.length == 1 ? Collections.singletonList(1) : Arrays.asList(1, 2));
     DeviceViewNode deviceViewNode =
@@ -456,7 +456,7 @@ public TestPlanBuilder deviceView(
       List<String> devices,
       Map<String, List<Integer>> deviceToMeasurementIndexesMap,
       List<PlanNode> children) {
-    Map<IDeviceID, List<Integer>> map = new HashMap<>();
+    Map<IDeviceID, List<Integer>> map = new LinkedHashMap<>();
     deviceToMeasurementIndexesMap.forEach(
         (key, value) -> map.put(IDeviceID.Factory.DEFAULT_FACTORY.create(key), value));
     DeviceViewNode deviceViewNode =