The InnoDB system tablespace is an opaque entity that contains essential system data, such as the transaction system state (undo logs could also be in separate tablespaces) and part of the data dictionary information.

Tablespaces cannot shrink in InnoDB, and the system tablespace cannot be reinitialized. If the system tablespace grows (for example, someone accidentally creates a huge table in it, or accidentally forgets to commit a transaction, causing undo logs to grow, or the change buffer grows for some reason), there is no other remedy than importing or loading the data to a newly initialized innoDB instance.

Similarly, if the system tablespace gets corrupted, it is ‘game over’.

This is an umbrella task consisting of subtasks to replace the various system objects stored in the InnoDB system tablespace. The actual work will be done in the subtasks.