Hi guys , I am bit confused about how a delete mload would work. I know there would not be any acquisition phase and data would be directly deleted from target tables .also no transient journal would be created. So if delete mload is aborted abruptly what would happen to the data?. How would it be recovered or rolled back?
It will not be recovered or rolled back. All forms of mload are designed to be restartable. It is expected that the mload would be restarted after the failure and would be allowed to complete. Recovery processes should be designed to restart and complete mload processes.
Like any other mload, if the mload is not completed, then the table is left in an inconsistent state which only allows full table reads or drop table operations. The base data is in an uncertain state with part of the operation performed and part not. Indexes are unlikely to be consistent with base data. Fallback is unlikely to be consistent with base data. It is allowed to read the data so that it can be copied to a new table to recover the base data and rebuild the dependent structures. Further operations will probably be required to complete or remove the operation to return the base data to a consistent state.
Again, recovery should be designed to restart and complete an mload that is interrupted.