042题库.docx

1. Because of a power outage,instance failure has occurred. From what point in the redo log does recovery begin and where does it end?A. Current redo log and inactive redo logB. Checkpoint position to end of redo logC. Beginning of redo log to end of redo logD. All redo logs before the point of last commitE. Beginning of redo log to checkpoint position.答案B. Checkpoint 之前的数据已经写入到数据文件。 所以用restore 就可以恢复。 而checkpoint之后的数据没有写入到数据文件，所以需要进行recovery。 Recovery时，对于已经commit的数据，前滚写入到数据文件。 没有commit的数据，进行回滚。2. Which two operations can be flashed back using the flashback technology? (choose two)A. Drop user smith;B. Drop table employees;C. Drop tablespace users;D. Alter table sales_rep drop partition p1;E. Alter table employees drop column desig_id;答案：AB。Oracle Flashback 技术 总结/tianlesoftware/archive/2009/10/16/4677378.aspx/tianlesoftware/archive/2009/10/16/4677378.aspx3. You have to shut down the database instance with the abort option because of a hardware failure. Which statement is true about the subsequent opening of the database?A. The database would open normally.B. The database would not open,and it would stop at mount stage.C. The database would open alter automatically performing instance recovery.D. The database would not open, and have to perform database recovery to open it.答案： C. 如果实例异常关闭（宕机，shutdown abort），并且数据文件，控制文件，联机日志都没有丢失。在下次启动时，要利用联机日志的内容进行恢复，这种恢复就是实例恢复（Instance Recovery）。Instance Recovery 主要包括3个阶段：1） 根据联机日志内容进行Rollover。2） 打开数据库，提供服务3） SMON 或者用户进程进行Rollback。具体参考 Oracle 备份与恢复概述 中的 3.2 节 恢复种类/tianlesoftware/archive/2010/04/16/5490733.aspx/tianlesoftware/archive/2010/04/16/5490733.aspx4. You backed up the control file to trace. Which statement is true about the trace file generated?A. The trace file is in binary format.B. The trace file has a SQL scripts to re-create the control file.C. The trace file is a backup set created during the backup of the control file.D. The trace file contains the instructions to manually re-create the control file.E. The trace file i