diff --git a/core/modules/system/system.install b/core/modules/system/system.install
index 292882776a..2b1a2a59b3 100644
--- a/core/modules/system/system.install
+++ b/core/modules/system/system.install
@@ -1447,13 +1447,3 @@ function system_update_8901() {
     }
   }
 }
-
-/**
- * Drop the 'all' index on the 'key_value_expire' table.
- */
-function system_post_update_9201() {
-  $schema = \Drupal::database()->schema();
-  if ($schema->tableExists('key_value_expire')) {
-    $schema->dropIndex('key_value_expire', 'all');
-  }
-}
diff --git a/core/modules/system/system.post_update.php b/core/modules/system/system.post_update.php
index 14391c15e9..6d09e99c0b 100644
--- a/core/modules/system/system.post_update.php
+++ b/core/modules/system/system.post_update.php
@@ -179,3 +179,13 @@ function system_post_update_delete_rss_settings() {
     ->clear('langcode')
     ->save();
 }
+
+/**
+ * Drop the 'all' index on the 'key_value_expire' table.
+ */
+function system_post_update_remove_key_value_expire_all_index() {
+  $schema = \Drupal::database()->schema();
+  if ($schema->tableExists('key_value_expire')) {
+    $schema->dropIndex('key_value_expire', 'all');
+  }
+}
diff --git a/core/modules/system/tests/src/Functional/Update/DropIndexAllOnKeyValueExpireTableUpdateTest.php b/core/modules/system/tests/src/Functional/Update/DropIndexAllOnKeyValueExpireTableUpdateTest.php
index 847016b6e9..1fe071ba34 100644
--- a/core/modules/system/tests/src/Functional/Update/DropIndexAllOnKeyValueExpireTableUpdateTest.php
+++ b/core/modules/system/tests/src/Functional/Update/DropIndexAllOnKeyValueExpireTableUpdateTest.php
@@ -8,7 +8,7 @@
  * Tests that 'all' index is dropped from the 'key_value_expire' table.
  *
  * @group Update
- * @see system_post_update_9201
+ * @see system_post_update_remove_key_value_expire_all_index()
  */
 class DropIndexAllOnKeyValueExpireTableUpdateTest extends UpdatePathTestBase {