Oracle OCP认证考试题库

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1、Oracle OCP认证考试题库Oracle OCP认证考试题库Oracle开发的关系数据库产品因性能卓越而著名，Oracle数据库产品为财宝排行榜上的前1000家公司所采纳，很多大型网站也选用了Oracle系统，是世界最好的数据库产品。以下是我整理的关于Oracle OCP认证考试题库，希望大家仔细阅读!QUESTION 1You notice that the performance of the database has degraded because of frequent checkpoints.Which two actions resolve the issue? (Choos

2、e two.)A. Disable automatic checkpoint tuningB. Check the size of the redo log file size and increase the size if it is smallC. Set the FAST_START_MTTR_TARGET parameter as per the advice given by the MTTR AdvisorD. Decrease the number of redo log members if there are more than one redo log members a

3、vailable in each redo log groupCorrect Answer: BCExplanation/Reference:检查点进程:The checkpoint process (CKPT) updates the control file and data file headers with checkpoint information and signals DBWn to write blocks to disk. Checkpoint information includes the checkpoint position, SCN, location in on

4、line redo log to begin recovery, and so on. CKPT does not write data blocks to data files or redo blocks to online redo log files.检查点作用:(1)定期促进DBWn进程把内存的脏块写回到数据文件,数据库故障时不会丢数据(2)削减实例复原的时间(3)确保全部已提交的数据在一样性关闭期间会被写入数据文件实例复原时间:指的是将数据文件的最终一个检查点(检查点位置)推动到限制文件中记录的最新SCN所需的.时间.管理员可以通过设置MTTR 目标以及调整重做日志组的大小来限制该

5、时间.MTTR:Mean Time To Repair,即平均修复时间.是指可修复产品的平均修复时间,就是从出现故障到修复中间的这段时间.MTTR越短表示易复原性越好.在数据库中可以通过设置参数FAST_START_MTTR_TARGET(单位为秒),限制数据库对单个实例执行崩溃复原所花费的时间.FAST_START_MTTR_TARGE=非0值, 启用快速启动检查点功能,自动限制发检查点速度.FAST_START_MTTR_TARGE=0,禁用快速启动检查点功能.假如重做日志文件的size太小,会频繁切换日志,即会频繁发生检查点,故可以增大重做日志文件的size削减检查点发生频率.FAST_

6、START_MTTR_TARGET假如设置的太小,为了要限制数据库单实例的实例复原时间，则必需频繁发生检查点,确保内存中已修改的数据块能够定期写入到磁盘,故可以运用MTTR Advisor来设置举荐的值.QUESTION 2Identify the memory component from which memory may be allocated for:Session memory for the shared server, Buffers for I/O slaves Oracle Database Recovery Manager (RMAN) backup and restore

7、 operationsA. Large PoolB. Redo Log BufferC. Database Buffer CacheD. Program Global Area (PGA)Correct Answer: AExplanation/Reference:Large PoolThe large pool is an optional memory area intended for memory allocations that are larger than is appropriate for the shared pool. The large pool can provide

8、 large memory allocations for the following:UGA for the shared server and the Oracle XA interface (used where transactions interact with multiple databases)Message buffers used in the parallel execution of statementsBuffers for Recovery Manager (RMAN) I/O slavesBy allocating session memory from the

9、large pool for shared SQL, the database avoids performance overhead caused by shrinking the shared SQL cache. By allocating memory in large buffers for RMAN operations, I/O server processes, and parallel buffers, the large pool can satisfy large memory requests better than the shared pool.QUESTION 3

10、You executed the following command to create a tablespace called SALES_DATA:SQL> CREATE TABLESPACE sales_dataDATAFILE SIZE 100MSEGMENT SPACE MANAGEMENT AUTO;Which two statements are true about the SALES_DATA tablespace? (Choose two)A. The database automatically determines the extent-sizing policy

11、 for the tablespace.B. The segments are automatically shrunk when the contents are removed from them.C. The allocation of extents within the tablespace is managed through the dictionary tables.D. The space utilization description of the data blocks in segments is recorded in bitmap blocks.E. The spa

12、ce utilization description of the data blocks in segments is managed through free lists.Correct Answer: ADExplanation/Reference:段空间管理: 本地管理的表空间中的段空间管理方式可指定为:自动:Oracle DB 运用位图管理段中的空闲空间.位图描述了段中每个数据块的状态,该状态与可插入行的块中的空间量有关.当数据块中可用空间增多或削减时,位图中会反映数据块的新状态.通过运用位图,Oracle DB 可以提高管理空闲空间的自动化程度.因此,这种空间管理方式称为"

13、;自动段空间管理(ASSM)".手动:此方法指定要运用空闲列表来管理段中的空闲空间.空闲列表是由一些数据块组成的列表,这些数据块中有可插入行的空间.由于这种管理段空间的方式须要为在表空间中创建的方案对象指定并优化PCTUSED、FREELISTS和FREELIST GROUPS存储参数,因此这种方式称为"手动段空间管理".支持运用此方法是为了向后兼容,建议运用ASSM.可通过dba_tablespaces查看分区和段空间管理方式:SYSENMOEDU> select tablespace_name,extent_management,segment_spac

14、e_management from dba_tablespaces;TABLESPACE_NAME EXTENT_MAN SEGMENSYSTEM LOCAL MANUALSYSAUX LOCAL AUTOTEMP LOCAL MANUALUSERS LOCAL AUTOEXAMPLE LOCAL AUTOUNDOTBS1 LOCAL MANUALQUESTION 4In which of the scenario will the DBA perform recovery? (Choose all that apply.)A. The alert log file is corruptedB

15、. A tablespace is accidentally droppedC. One of the redo log members is corruptedD. A database user terminates the session abnormallyE. The hard disk on which the data files is stored is corruptedCorrect Answer: BEExplanation/Reference:DBA一般在数据库出现介质损坏的时候执行复原操作.A: 错误,alert日志损坏数据库不会丢失数据,不须要复原.B: 正确,表空间在操作系统改名须要执行复原,数据库找不到表空间对应的数据文件.C: 错误,丢失redo成员,不会丢失数据,不须要执行复原操作.D: 错误,会话异样终止不会丢失数据,不须要复原,数据库会释放异样会话占用的资源.E: 正确,磁盘损坏会导致在该磁盘的数据文件损坏,须要执行复原操作.本文来源：网络收集与整理，如有侵权，请联系作者删除，谢谢！第1页 共1