On a Drupal installation with a large number of configuration files (I have one with over 1,900), It is not possible to update Drupal core to 9.3.0. When the update gets to the "sort_all_config" post-update hook, that hook fails with allowed memory exhausted.
The function system_post_update_sort_all_config() in system.post_update.php attempts to update all configuration files in a single execution. This should be converted to a batch process.
Review the patch file provided in this issue.
TBD
Fixed
9.3
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