Here a very good overview about the combinations when Redo-Log is generated or not for inserts with and without logging/append-hint/archive-log-mode. Found by asktom.
Check DB for archive-log-mode turned on or off:
select log_mode from v$database;
Check for logging-mode for table:
select logging from all_tables
where owner = '<USER>'
and table_name = '<TABLE_NAME>';
Example for Direct-Path-Insert with append-hint:
insert into '<TABLE_NAME>' /*+ append */
select * from all_objects;
TableMode Insert Mode ArchiveLogMode result
---------- ----------- --------------- ----------
LOGGING APPEND ARCHIVE LOG redogenerated
NOLOGGING APPEND ARCHIVE LOG no redo
LOGGING no append "" redogenerated
NOLOGGING no append "" redogenerated
LOGGING APPEND noarchive no redo
NOLOGGING APPEND noarchive no redo
LOGGING no append noarchive redogenerated
NOLOGGING no append noarchive redogenerated
If „FORCE LOGGING“ is used, than of course redo is generated!