Performance Fix for Large Catalogs

Refer to this thread for the full issue.
magento/magento2#278

We confirmed this issue Exists in Magento EE 1.13 Where for large
catalogs we were experiencing out of memory issues due to this function
_loadSkuSuperAttributeValues()

This patch will help those stores with large amounts of configurable
products process large imports with hundreds of thousands of rows
without hitting this issue as a
bottleneck

src/app/code/community/AvS/FastSimpleImport/Model/Import/Entity/Product/Type/Configurable.php

@@ -125,6 +125,47 @@ protected function _isSkuNew($sku)
         return !isset($oldSkus[$sku]);
     }
 
+    /**
+     * Array of SKU to array of super attribute values for all products.
+     *
+     * @return Mage_ImportExport_Model_Import_Entity_Product_Type_Configurable
+     */
+    protected function _loadSkuSuperAttributeValues($bunch, $newSku, $oldSku)
+    {
+        if ($this->_superAttributes) {
+            $attrSetIdToName   = $this->_entityModel->getAttrSetIdToName();
+            $allowProductTypes = array();
+
+            foreach ($bunch as $rowData){
+                if (!empty($rowData['_super_products_sku'])) {
+                    if (isset($newSku[$rowData['_super_products_sku']])) {
+                        $productIdArray[] = $newSku[$rowData['_super_products_sku']];
+                    } elseif (isset($oldSku[$rowData['_super_products_sku']])) {
+                        $productIdArray[] = $oldSku[$rowData['_super_products_sku']];
+                    }
+                }
+            }
+            foreach (Mage::getConfig()
+                    ->getNode('global/catalog/product/type/configurable/allow_product_types')->children() as $type) {
+                $allowProductTypes[] = $type->getName();
+            }
+            foreach (Mage::getResourceModel('catalog/product_collection')
+                        ->addFieldToFilter('type_id', $allowProductTypes)
+                        ->addFieldToFilter ('entity_id', array('in' => $productIdArray))
+                        ->addAttributeToSelect(array_keys($this->_superAttributes)) as $product) {
+                $attrSetName = $attrSetIdToName[$product->getAttributeSetId()];
+                $data = array_intersect_key(
+                    $product->getData(),
+                    $this->_superAttributes
+                );
+                foreach ($data as $attrCode => $value) {
+                    $attrId = $this->_superAttributes[$attrCode]['id'];
+                    $this->_skuSuperAttributeValues[$attrSetName][$product->getId()][$attrId] = $value;
+                }
+            }
+        }
+        return $this;
+    }
 
     /**
      * Save product type specific data.
@@ -149,7 +190,6 @@ public function saveData()
         if ($this->_entityModel->getBehavior() == Mage_ImportExport_Model_Import::BEHAVIOR_APPEND) {
             $this->_loadSkuSuperData();
         }
-        $this->_loadSkuSuperAttributeValues();
 
         while ($bunch = $this->_entityModel->getNextBunch()) {
             $superAttributes = array(
@@ -159,6 +199,9 @@ public function saveData()
                 'super_link' => array(),
                 'relation'   => array()
             );
+
+            $this->_loadSkuSuperAttributeValues($bunch, $newSku, $oldSku);
+
             foreach ($bunch as $rowNum => $rowData) {
                 if (!$this->_entityModel->isRowAllowedToImport($rowData, $rowNum)) {
                     continue;