Complete database recovery from disk failure is possible only i
n ARCHIVELOG mode.
Online database backup is possible only in ARCHIVELOG mode.
The point at which ORACLE ends writing to one online redo log file and begins writing to another is called a log switch.
Rolling forward to recover data that has not been recorded in data files, yet has been recorded in the on-line redo log, including the contents of rollback segments.
Rolling back transactions that have been explicitly rolled back or have not been committed as indicated by the rollback segments regenerated in step a.
Releasing any resources (locks) held by transactions in process at the time of the failure.
Resolving any pending distributed transactions undergoing a two-phase commit at the time of the instance failure.
DDL IS A AUTO COMMIT, YOU DON􀂶T NEED TO COMMIT AGAIN
USING COMMENT LINES WITH (+) SIGN YOU CAN PASS THE HINTS TO SQL ENGINE
/* +PARALLEL( ) */