Let us have a look at a few known limitations of data dictionary:
- Individual MyISAM tables for backup and restore are not supported by merely copying the files.
- Manually created directories for databases are not supported by MySQL 8. For instance, using mkdir would have no impact on MySQL server data dictionary.
- DDL operations would take more time than expected because such operations are written to storage, undo logs and redo instead of .frm files as what we would have seen in prior versions of MySQL.