Use of Rollback

Question

Good morning.
I need to know if sentences like "CREATE TABLE AS SELECT..." or "INSERT /*+APPEND*/ INTO..." use the rollback segment or not.
I need to find any form to create and load tables without using the rollback segment.
Coul you help me?
Thank you very much for your help.

Answer 1

Do you want to minimize Redo logging or Undo
(rollback)?
INSERT /*+ APPEND */ is a method to minimize
redo logging. It uses undo like any other
insert statement and can be rolled back.The above statement is "Not true!".
APPEND means "use direct insert". This means UNDO will not be logged. This has no direct effect on redo. If the table you are inserting into has USER_TABLES.LOGGING='N', then in addition to undo not being logged, redo will also not be logged. Also, other operations can specify nologging on the command line, such as CTAS or index creates and rebuilds, but those operations, by their very nature, are direct path loads.
Bottom line is this:
If you're not doing direct path, nologging has no effect. The only place that nologging has any effect is direct path loads. Direct path loads, by definition, avoid writing undo.
Further, in a noarchivelog mode database, direct path load implies nologging. On an archivelog mode database, if you want to avoid redo generation on a direct path load, you have to ask for it explicitly. But, undo is always avoided for direct path loads.
Hope thats clear,
-Mark