diff --git b/core/lib/Drupal/Core/Entity/Sql/SqlContentEntityStorageSchema.php a/core/lib/Drupal/Core/Entity/Sql/SqlContentEntityStorageSchema.php
index 29c6aebb41..6763aad83b 100644
--- b/core/lib/Drupal/Core/Entity/Sql/SqlContentEntityStorageSchema.php
+++ a/core/lib/Drupal/Core/Entity/Sql/SqlContentEntityStorageSchema.php
@@ -1668,15 +1668,10 @@ protected function updateSharedTableSchema(FieldStorageDefinitionInterface $stor
               }
             }
             // Create new primary key, indexes and unique keys.
-            // The entity schema needs to be checked because the field schema is
-            // potentially incomplete.
-            // @todo Remove this in
-            //   https://www.drupal.org/project/drupal/issues/2929120
-            $entity_schema = $this->getEntitySchema($this->entityType);
             foreach ($schema[$table_name]['fields'] as $name => $specifier) {
               // Check if the field is part of the primary keys.
-              if (isset($entity_schema[$table_name]['primary key']) && array_intersect($column_names, $entity_schema[$table_name]['primary key'])) {
-                $schema_handler->addPrimaryKey($table_name, $entity_schema[$table_name]['primary key']);
+              if (isset($schema[$table_name]['primary key']) && array_intersect($column_names, $schema[$table_name]['primary key'])) {
+                $schema_handler->addPrimaryKey($table_name, $schema[$table_name]['primary key']);
 
                 // If the field being updated is a serial field, it will have
                 // been changed to an integer field by