From affecea882bbaaf47bd15649cc807b01672bfa3b Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?=C5=81ukasz=20Bajsarowicz?= <lukasz@lbajsarowicz.me>
Date: Thu, 6 Aug 2026 01:23:57 +0200
Subject: [PATCH] Build flat table column and index maps in one array_merge
 call

getFlatColumns() and getFlatIndexes() merged every attribute's contribution
into the accumulated map on each iteration, so each iteration copied the whole
map built so far. Both loops run once per flat attribute, which makes the cost
grow with the square of the attribute count.

Collect the per-attribute maps and merge them once with argument unpacking. The
merge order is unchanged, so a later attribute still overrides an earlier key
exactly as before, and the phpcs:ignore annotations for
Magento2.Performance.ForeachArrayMerge are no longer needed.
---
 .../Magento/Catalog/Helper/Product/Flat/Indexer.php   | 11 ++++++-----
 1 file changed, 6 insertions(+), 5 deletions(-)

diff --git a/app/code/Magento/Catalog/Helper/Product/Flat/Indexer.php b/app/code/Magento/Catalog/Helper/Product/Flat/Indexer.php
index 040200f536243..9ae1ca79d839d 100644
--- a/app/code/Magento/Catalog/Helper/Product/Flat/Indexer.php
+++ b/app/code/Magento/Catalog/Helper/Product/Flat/Indexer.php
@@ -246,7 +246,7 @@ public function isAddChildData()
     public function getFlatColumns()
     {
         if ($this->_columns === null) {
-            $this->_columns = $this->getFlatColumnsDdlDefinition();
+            $columnsPerAttribute = [$this->getFlatColumnsDdlDefinition()];
             foreach ($this->getAttributes() as $attribute) {
                 /** @var $attribute \Magento\Eav\Model\Entity\Attribute\AbstractAttribute */
                 $columns = $attribute->setFlatAddFilterableAttributes(
@@ -255,10 +255,10 @@ public function getFlatColumns()
                     $this->isAddChildData()
                 )->getFlatColumns();
                 if ($columns !== null) {
-                    // phpcs:ignore Magento2.Performance.ForeachArrayMerge
-                    $this->_columns = array_merge($this->_columns, $columns);
+                    $columnsPerAttribute[] = $columns;
                 }
             }
+            $this->_columns = array_merge(...$columnsPerAttribute);
         }
         return $this->_columns;
     }
@@ -409,6 +409,7 @@ public function getFlatIndexes()
                 'fields' => ['attribute_set_id'],
             ];
 
+            $indexesPerAttribute = [$this->_indexes];
             foreach ($this->getAttributes() as $attribute) {
                 /** @var $attribute \Magento\Eav\Model\Entity\Attribute */
                 $indexes = $attribute->setFlatAddFilterableAttributes(
@@ -417,10 +418,10 @@ public function getFlatIndexes()
                     $this->isAddChildData()
                 )->getFlatIndexes();
                 if ($indexes !== null) {
-                    // phpcs:ignore Magento2.Performance.ForeachArrayMerge
-                    $this->_indexes = array_merge($this->_indexes, $indexes);
+                    $indexesPerAttribute[] = $indexes;
                 }
             }
+            $this->_indexes = array_merge(...$indexesPerAttribute);
         }
         return $this->_indexes;
     }