单项选择题
Your database instance is configured with automatic undo management and the UNDO_RETENTION parameter is set to 900 seconds. You executed the following command to enable retention guarantee： SQL> ALTER TABLESPACE undotbs1 RETENTION GUARANTEE； What effect would this command have on the database（）
A.The extents in the undo tablespace retain data until the next full database backup.
B.The extents containing committed undo in the undo tablespace are not overwritten for at least 15minutes.
C.The extents containing committed data in the undo tablespace are not overwritten until the instance isshut down.
D.The extents containing committed undo in the undo tablespace are transferred to Flash Recovery Areabefore being overwritten.
相关考题
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单项选择题
View the Exhibit and examine the undo tablespace attributes. Your database instance is experiencing a large volume of transactions from non-DBA users in the last onehour. The undo tablespace UNDOTBS1 is full with transactions and no transaction was committed morethan one hour ago. The database has two more undo tablespaces. What happens to the new DML operations in this scenario（）
A.The DML commands will fail.
B.The undo data generated by the DML is stored in one of the two other undo tablespaces.
C.The undo data generated by the DML will overwrite the extents that contain committed undo data.
D.The undo data generated by the DML is stored in the SYSTEM undo segment of the SYSTEM -
多项选择题
Whichtwostatementsaretrueregardingundotablespaces（）
A.The database can have more than one undo tablespace.
B.The UNDO_TABLESPACE parameter is valid in both automatic andmanualundo management.
C.Undo segments automatically grow and shrink as needed， acting as circular storage buffer for their assigned transactions.
D.An undotablespaceis automatically created if the UNDO_TABLESPACEparameter is not set and the UNDO_MANAGEMENT parameter is set to AUTO during the database instance start up. -
多项选择题
Whichthreeoperationsrequireundodata（）
A.committing a transaction
B.flashing back a transaction
C.recovering a failed transaction
D.running a read-consistent query
E.changing a tablespace status from READ ONLY to READ WRITE
