create tablespace 中的logging模式

from_now

LOGGING| NOLOGGING specifies the default logging attributes of all tables, indexes, and partitions within the tablespace. LOGGING is the default.  

The tablespace-level logging attribute can be overridden by logging specifications at the table, index, and partition levels. 

Only the following operations support the NOLOGGING mode: 

DML: direct-load INSERT (serial or parallel), Direct Loader (SQL*Loader) 

DDL: CREATE TABLE ... AS SELECT, CREATE INDEX, ALTER INDEX ... REBUILD, ALTER INDEX ... REBUILD PARTITION, ALTER INDEX ... SPLIT PARTITION, ALTER TABLE ... SPLIT PARTITION, and ALTER TABLE ... MOVE PARTITION  

In NOLOGGING mode, data is modified with minimal logging (to mark new extents INVALID and to record dictionary changes). When applied during media recovery, the extent invalidation records mark a range of blocks as logically corrupt, because the redo data is not logged. Therefore, if you cannot afford to lose the object, you should take a backup after the NOLOGGING operation.