該參數是Oracle 11g新增的參數。
DB_ULTRA_SAFE參數整合了DB_BLOCK_CHECKING, DB_BLOCK_CHECKSUM, 和 DB_LOST_WRITE_PROTECT三個參數。
DB_ULTRA_SAFE ={ OFF | DATA_ONLY | DATA_AND_INDEX },默認值爲OFF。
當DB_ULTRA_SAFE 設置爲:
(1)OFF:
When any of DB_BLOCK_CHECKING, DB_BLOCK_CHECKSUM, or DB_LOST_WRITE_PROTECT areexplicitly set, no changes are made.
--不改變這三個參數的值。
(2)DATA_ONLY:
三個參數會按照如下方式進行修改:
DB_BLOCK_CHECKING will be set to MEDIUM.
DB_LOST_WRITE_PROTECT will be set to TYPICAL.
DB_BLOCK_CHECKSUM will be set to FULL.
(3)DATA_AND_INDEX:
三個參數會按照如下方式進行修改:
DB_BLOCK_CHECKING will be set to FULL.
DB_LOST_WRITE_PROTECT will be set to TYPICAL.
DB_BLOCK_CHECKSUM will be set to FULL.
查看db_ultra_safe 參數:show parameter db_ultra_safe
修改db_ultra_safe 爲data_only:
alter system setdb_ultra_safe=data_only scope=spfile; --需要重啓實例