MC-22212: 1213 Deadlock found when trying to get lock

Author: dhorytskyi

app/code/Magento/Indexer/Model/ResourceModel/AbstractResource.php

@@ -141,7 +141,9 @@ public function insertFromSelect($select, $destTable, array $columns, $readToInd
 
         if ($from === $to) {
             $query = $select->insertFromSelect($destTable, $columns);
-            $to->query('SET TRANSACTION ISOLATION LEVEL READ COMMITTED;');
+            if ($to->getTransactionLevel() === 0) {
+                $to->query('SET TRANSACTION ISOLATION LEVEL READ COMMITTED;');
+            }
             $to->query($query);
         } else {
             $stmt = $from->query($select);