#40216-Replacing nested foreach with array union (+) to reduce time complexity

app/code/Magento/Eav/Model/Entity/Collection/AbstractCollection.php

@@ -1,6 +1,6 @@
 <?php
 /**
- * Copyright 2013 Adobe
+ * Copyright 2025 Adobe
  * All Rights Reserved.
  */
 
@@ -1233,8 +1233,27 @@ public function _loadAttributes($printQuery = false, $logQuery = false)
                     throw $e;
                 }
 
+                $attributeCode = $data = [];
+                $entityIdField = $entity->getEntityIdField();
+
                 foreach ($values as $value) {
-                    $this->_setItemAttributeValue($value);
+                    $entityId = $value[$entityIdField];
+                    $attributeId = $value['attribute_id'];
+                    if (!isset($attributeCode[$attributeId])) {
+                        $attributeCode[$attributeId] = array_search($attributeId, $this->_selectAttributes);
+                        if (!$attributeCode[$attributeId]) {
+                            $attribute = $this->_eavConfig->getAttribute(
+                                $this->getEntity()->getType(),
+                                $attributeId
+                            );
+                            $attributeCode[$attributeId] = $attribute->getAttributeCode();
+                        }
+                    }
+                    $data[$entityId][$attributeCode[$attributeId]] = $value['value'];
+                }
+
+                if ($data) {
+                    $this->_setItemAttributeValues($data);
                 }
             }
         }
@@ -1305,6 +1324,9 @@ protected function _addLoadAttributesSelectValues($select, $table, $type)
      *
      * Parameter $valueInfo is _getLoadAttributesSelect fetch result row
      *
+     * @deprecated Batch process of attribute values is introduced to reduce time complexity.
+     * @see _setItemAttributeValues($entityAttributeMap) uses array union (+) to acheive O(n) complexity.
+     *
      * @param array $valueInfo
      * @return $this
      * @throws LocalizedException
@@ -1334,6 +1356,33 @@ protected function _setItemAttributeValue($valueInfo)
         return $this;
     }
 
+    /**
+     * Initialize entity object property value
+     *
+     * Parameter $entityAttributeMap is [entity_id => [attribute_code => value, ...]]
+     *
+     * @param array $entityAttributeMap
+     * @return $this
+     * @throws LocalizedException
+     */
+    protected function _setItemAttributeValues(array $entityAttributeMap)
+    {
+        foreach ($entityAttributeMap as $entityId => $attributeValues) {
+            if (!isset($this->_itemsById[$entityId])) {
+                throw new LocalizedException(
+                    __('A header row is missing for an attribute. Verify the header row and try again.')
+                );
+            }
+            // _itemsById[$entityId] is always an array (typically with one element)
+            // foreach handles edge cases where multiple objects share the same entity ID
+            foreach ($this->_itemsById[$entityId] as $object) {
+                $object->setData($object->getData()+$attributeValues);
+            }
+
+        }
+        return $this;
+    }
+
     /**
      * Get alias for attribute value table
      *