13. Size of a Table File

• innodb_file_per_table determines whether InnoDB stores data for each table in an independent file
• What happens when a row is deleted:
  • InnoDB marks a slot as deleted and ready for reuse, rather than really moving its positions on disk
  • Thus, deleting data too frequently may result in disk fragmentation
• Rebuild a table using ALTER TABLE ... could reduce disk fragmentation
• An online DDL must be an in-place operation, an in-place operation may not be online