Improve attribute checking

On a store with a large number of attribute sets, a lot of repeated checking is done for the same attributes.
So instead we can keep track of the attributes we already checked, and skip them the next time.

Author: Freek Vandeursen

app/code/Magento/CatalogImportExport/Model/Import/Product/Type/AbstractType.php

@@ -28,6 +28,13 @@ abstract class AbstractType
      */
     public static $commonAttributesCache = [];
 
+    /**
+     * Maintain a list of invisible attributes
+     *
+     * @var array
+     */
+    public static $invisibleAttributesCache = [];
+
     /**
      * Attribute Code to Id cache
      *
@@ -278,7 +285,10 @@ protected function _initAttributes()
             }
         }
         foreach ($absentKeys as $attributeSetName => $attributeIds) {
-            $this->attachAttributesById($attributeSetName, $attributeIds);
+            $unknownAttributeIds = array_diff($attributeIds, array_keys(self::$commonAttributesCache), self::$invisibleAttributesCache);
+            if ($unknownAttributeIds) {
+                $this->attachAttributesById($attributeSetName, $attributeIds);
+            }
         }
         foreach ($entityAttributes as $attributeRow) {
             if (isset(self::$commonAttributesCache[$attributeRow['attribute_id']])) {
@@ -310,30 +320,35 @@ protected function attachAttributesById($attributeSetName, $attributeIds)
             $attributeId = $attribute->getId();
 
             if ($attribute->getIsVisible() || in_array($attributeCode, $this->_forcedAttributesCodes)) {
-                self::$commonAttributesCache[$attributeId] = [
-                    'id' => $attributeId,
-                    'code' => $attributeCode,
-                    'is_global' => $attribute->getIsGlobal(),
-                    'is_required' => $attribute->getIsRequired(),
-                    'is_unique' => $attribute->getIsUnique(),
-                    'frontend_label' => $attribute->getFrontendLabel(),
-                    'is_static' => $attribute->isStatic(),
-                    'apply_to' => $attribute->getApplyTo(),
-                    'type' => \Magento\ImportExport\Model\Import::getAttributeType($attribute),
-                    'default_value' => strlen(
-                        $attribute->getDefaultValue()
-                    ) ? $attribute->getDefaultValue() : null,
-                    'options' => $this->_entityModel->getAttributeOptions(
-                        $attribute,
-                        $this->_indexValueAttributes
-                    ),
-                ];
+                if (!isset(self::$commonAttributesCache[$attributeId])) {
+                    self::$commonAttributesCache[$attributeId] = [
+                        'id' => $attributeId,
+                        'code' => $attributeCode,
+                        'is_global' => $attribute->getIsGlobal(),
+                        'is_required' => $attribute->getIsRequired(),
+                        'is_unique' => $attribute->getIsUnique(),
+                        'frontend_label' => $attribute->getFrontendLabel(),
+                        'is_static' => $attribute->isStatic(),
+                        'apply_to' => $attribute->getApplyTo(),
+                        'type' => \Magento\ImportExport\Model\Import::getAttributeType($attribute),
+                        'default_value' => strlen(
+                            $attribute->getDefaultValue()
+                        ) ? $attribute->getDefaultValue() : null,
+                        'options' => $this->_entityModel->getAttributeOptions(
+                            $attribute,
+                            $this->_indexValueAttributes
+                        ),
+                    ];
+                }
+
                 self::$attributeCodeToId[$attributeCode] = $attributeId;
                 $this->_addAttributeParams(
                     $attributeSetName,
                     self::$commonAttributesCache[$attributeId],
                     $attribute
                 );
+            } else {
+                self::$invisibleAttributesCache[] = $attributeId;
             }
         }
     }