系统表空间是在创建数据库时一同创建的,它用于存储数据字典对象,并且包含系统回滚段(System Undo Segment)。
什么是UNDO操作和REDO操作?为什么要这样设置?
Which method would you use to undo the changes made by a particular transaction without affecting the changes made by other transactions?()
View the Exhibit and examine the attributes of an undo tablespace. In an OLTP system, the user SCOTT has started a query on a large table in the peak transactional hourthat performs bulk inserts. The query runs for more than 15 minutes and then SCOTT receives thefollowing error: ORA-01555: snapshot too old What could be the reason for this error()
Which of the following Oracle features utilize the undo tablespace?()
Your database instance is configured with automatic undo management and the UNDO_RETENTIONparameter 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 onthe database()
You set the undo pool resource plan directive for the consumer group named DSS_USERS that is assigned to the DAY_SHIFT plan. The database users, SCOTT and BLAKE, belong to the DSS_USERS resource group. The user, SCOTT, initiates a database session and executes a batch operation that inserts millions of rows into the HISTORY table. Which two options are true if the total undo space allocated to the DSS_USERS group exceeds the value specified in the undo pool resource plan directive?()
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()
You have a long-running process you want to assign to a specific UNDO segment brought online for that express purpose. You are not using automatic UNDO management. What statement can be used for this task? ()
系统表空间是在创建数据库时一同创建的,它用于存储数据字典对象,并且包含系统回滚段(System Undo Segment)。