Return comparable LinkedHashMap in valueForCalcite() of ExprTupleValue

core/src/main/java/org/opensearch/sql/data/model/ExprTupleValue.java

@@ -14,6 +14,7 @@
 import lombok.RequiredArgsConstructor;
 import org.opensearch.sql.data.type.ExprCoreType;
 import org.opensearch.sql.data.type.ExprType;
+import org.opensearch.sql.data.utils.ComparableLinkedHashMap;
 import org.opensearch.sql.storage.bindingtuple.BindingTuple;
 import org.opensearch.sql.storage.bindingtuple.LazyBindingTuple;
 
@@ -44,7 +45,7 @@ public Object value() {
 
   @Override
   public Object valueForCalcite() {
-    LinkedHashMap<String, Object> resultMap = new LinkedHashMap<>();
+    ComparableLinkedHashMap<String, Object> resultMap = new ComparableLinkedHashMap<>();
     for (Entry<String, ExprValue> entry : valueMap.entrySet()) {
       resultMap.put(entry.getKey(), entry.getValue().valueForCalcite());
     }

core/src/main/java/org/opensearch/sql/data/utils/ComparableLinkedHashMap.java

@@ -0,0 +1,46 @@
+/*
+ * Copyright OpenSearch Contributors
+ * SPDX-License-Identifier: Apache-2.0
+ */
+
+package org.opensearch.sql.data.utils;
+
+import java.util.LinkedHashMap;
+
+public class ComparableLinkedHashMap<K, V> extends LinkedHashMap<K, V>
+    implements Comparable<ComparableLinkedHashMap<K, V>> {
+
+  public ComparableLinkedHashMap() {
+    super();
+  }
+
+  public ComparableLinkedHashMap(int initialCapacity) {
+    super(initialCapacity);
+  }
+
+  public ComparableLinkedHashMap(int initialCapacity, float loadFactor) {
+    super(initialCapacity, loadFactor);
+  }
+
+  @Override
+  public int compareTo(ComparableLinkedHashMap<K, V> other) {
+    if (this.isEmpty() && other.isEmpty()) {
+      return 0;
+    }
+    if (this.isEmpty()) {
+      return -1;
+    }
+    if (other.isEmpty()) {
+      return 1;
+    }
+
+    V thisFirstValue = this.values().iterator().next();
+    V otherFirstValue = other.values().iterator().next();
+
+    if (thisFirstValue instanceof Comparable) {
+      return ((Comparable) thisFirstValue).compareTo(otherFirstValue);
+    }
+
+    return thisFirstValue.toString().compareTo(otherFirstValue.toString());
+  }
+}

integ-test/src/yamlRestTest/resources/rest-api-spec/test/issues/4339.yml

@@ -0,0 +1,80 @@
+setup:
+  - do:
+      indices.create:
+        index: test
+        body:
+          settings:
+            number_of_shards: 1
+            number_of_replicas: 0
+          mappings:
+            properties:
+              log:
+                properties:
+                  url:
+                    properties:
+                      message:
+                        type: text
+                        fields:
+                          keyword:
+                            type: keyword
+                            ignore_above: 256
+                      time:
+                        type: long
+              message_alias:
+                type: alias
+                path: log.url.message
+              time_alias:
+                type: alias
+                path: log.url.time
+
+  - do:
+      query.settings:
+        body:
+          transient:
+            plugins.calcite.enabled : true
+
+---
+teardown:
+  - do:
+      query.settings:
+        body:
+          transient:
+            plugins.calcite.enabled : false
+
+---
+"dedup struct field":
+  - skip:
+      features:
+        - headers
+  - do:
+      bulk:
+        index: test
+        refresh: true
+        body:
+          - '{"index": {}}'
+          - '{"log": {"url": {"message": "/e2e/h/zap", "time": 1} } }'
+          - '{"index": {}}'
+          - '{"log": {"url": {"message": "/e2e/h/zap", "time": 1} } }'
+          - '{"index": {}}'
+          - '{"log": {"url": {"message": "/e2e/h/zap", "time": 2} } }'
+          - '{"index": {}}'
+          - '{"log": {"url": {"message": "/e2e/h/zap", "time": 2} } }'
+          - '{"index": {}}'
+          - '{"log": {"url": {"message": "/e2e/h/aap", "time": 1} } }'
+          - '{"index": {}}'
+          - '{"log": {"url": {"message": "/e2e/h/aap", "time": 1} } }'
+          - '{"index": {}}'
+          - '{"log": {"url": {"time": 1} } }'
+          - '{"index": {}}'
+          - '{"log": {"url": {"time": 1} } }'
+          - '{"index": {}}'
+          - '{"log": {"url": {"time": 2} } }'
+          - '{"index": {}}'
+          - '{"log": {"url": {"time": 2} } }'
+  - do:
+      headers:
+        Content-Type: 'application/json'
+      ppl:
+        body:
+          query: 'source=test | dedup log'
+  - match: {"total": 5}