多选题Which two statements are true about checkpointing（）AThe checkpoint frequency decreases with the smaller redo log file size.BIt ensures that all committed data is written to the data files during normal shutdown.CThe frequent full checkpoint in a databa

题目
多选题
Which two statements are true about checkpointing（）
A

The checkpoint frequency decreases with the smaller redo log file size.

B

It ensures that all committed data is written to the data files during normal shutdown.

C

The frequent full checkpoint in a database can cause the overall degradation of the database performance.

D

It prompts the Checkpoint （CKPT） process to write data to the data files and redo information to the online redo log files.

相似考题

1.You performed the RMAN database backup with the KEEP option.Which two statements are true about this backup?() (Choose two)A. The KEEP option overrides the configured retention policyB. The KEEP option is an attribute of an individual backup pieceC. The backup contains only data files and archived redo log filesD. The backup contains data files, the server parameter file and the control file even if the control file auto backup is disabled

2. The instance abnormally terminates because of a power outage.  Which statement is true about redo log filesduring instance recovery（）A、Inactive and current redo log files are required to accomplish recovery.B、Online and archived redo log files are required to accomplish instance recovery.C、All redo log entries after the last checkpoint are applied from redo log files to data files.D、All redo log entries recorded in the current redo log file until the checkpoint position are applied to data files

3.Which statement is true regarding the Archiver （ARCn） process，archived log files，and recovery？ （）A、A database backup, combined with archived redo log files, guarantees that all committed data can be recovered to the point of failure. B、During recovery the ARCn background process copies its redo entries identified for recovery by the control file to the data files. C、After each write to an archived log, the mandatory background process ARCn writes its log sequence number and the first and last SCN number within the log sequence to the control file. D、At database recover time, and archived redo log is uniquely identified for recovery use by its redo thread number and destination ID number retrieved from the control file.

4.Examine the following scenario:The target database instance is running. The most recent backup available for the target database was taken two days ago. Log files switches have occurred in last two days. The target database is duplicated on the same host, using the Recovery Manager (RMAN) duplicate command as follows:Which statement is true about the duplicate database in this scenario?（）A. It contains data till the last backupB. It contains all data from target database until the current timeC. It contains all data from only the committed transactions in the target databaseD. It contains all data except that which is used by the transactions in the current online redo file of target database

更多“多选题Which two statements are true about checkpointing（）AThe checkpoint frequency decreases with the smaller redo log file size.BIt ensures that all committed data is written to the data files during normal shutdown.CThe frequent full checkpoint in a databa”相关问题

  • 第1题：

    Which  statements are true about checkpointing（）

    • A、The checkpoint frequency decreases with the smaller redo log file size.
    • B、It ensures that all committed data is written to the data files during normal shutdown.
    • C、The frequent full checkpoint in a database can cause the overall degradation of the database performance.
    • D、It prompts the Checkpoint （CKPT） process to write data to the data files and redo information to the onlineredo log files

    正确答案:B,C

  • 第2题：

    You performed the RMAN database backup with the KEEP option.Which two statements are true about this backup?（） (Choose two)

    • A、The KEEP option overrides the configured retention policy
    • B、The KEEP option is an attribute of an individual backup piece
    • C、The backup contains only data files and archived redo log files
    • D、The backup contains data files, the server parameter file and the control file even if the control file auto backup is disabled

    正确答案:A,D

  • 第3题：

    Which three statements are true about the stages of database startup？（）

    • A、Data files and redo log files can be renamed at the MOUNT stage.
    • B、Control files are read at the OPEN stage for the location of data files.
    • C、Control files are required to bring the database to the NOMOUNT stage.
    • D、Data files and redo log files are made available to users at the OPEN stage.
    • E、Data files and online redo log files are checked for consistency while opening the database

    正确答案:A,D,E

  • 第4题：

    Which two statements about the background process of the database writer are true（）

    • A、It is possible to have multiple database writers in an Oracle instance.
    • B、It writes dirty buffers， if any， to data files whenever a checkpoint occurs.
    • C、It writes dirty buffers， if any， to data files whenever a transaction commits.
    • D、It writes dirty buffers， if any， to data files before the log writer （LGWR） writes

    正确答案:A,B

  • 第5题：

    Which two statements about the background process of thedatabase writerare true（） 

    • A、It is possible to have multiple database writers in an Oracle instance.
    • B、It writes dirty buffers， if any， to data files whenever a checkpoint occurs.
    • C、It writes dirty buffers， if any， to data files whenever a transaction commits.
    • D、It writes dirty buffers， if any， to data files before the log writer （LGWR） writes.

    正确答案:A,B

  • 第6题：

    Which three statements are true about database recovery operations？（）

    • A、Damaged or lost data files are restored from backups.
    • B、Redo log file entries are used to roll forward the database.
    • C、Undo segments are used to roll back any uncommitted transactions.
    • D、Transactions that were active when the failure occurred are restarted.
    • E、Transactions that were active when the failure occurred are automatically committed during the recover procedure.

    正确答案:A,B,C

  • 第7题：

    多选题
    After performing a clean shut down of the database instance for maintenance， you mount the database andthen execute a command to open the database：SQL> ALTER DATABASE OPEN； Which two statements are true（）
    A

    The online redo log files and online data files are opened.

    B

    All the online data file headers are checked for consistency.

    C

    Instance recovery is performed before opening the database.

    D

    The path and existence of all the log file members are checked


    正确答案： C,A
    解析： 暂无解析

  • 第8题：

    单选题
    Which statement is true regarding checkpoints and recovery？（）
    A

    A checkpoint defines the highest system change number （SCN）.

    B

    All redo entries higher or at the SCN are known to be written to the data files.

    C

    Only the redo records containing SCNs higher then the checkpoint need to be applied during recovery.

    D

    The LOG_CHECKPOINT_INTERVAL initialization parameter specifies the amount of time between incremental checkpoints.


    正确答案： D
    解析： 暂无解析

  • 第9题：

    多选题
    The loss of which two types of files may require a recovery with the RESETLOGS option？（）
    A

    control files

    B

    password file

    C

    archived log files

    D

    system-critical data files for which all the redo entries are present

    E

    non-system-critical data files for which all the redo entries are present


    正确答案： B,C
    解析： 暂无解析

  • 第10题：

    多选题
    Which  statements are true about checkpointing（）
    A

    The checkpoint frequency decreases with the smaller redo log file size.

    B

    It ensures that all committed data is written to the data files during normal shutdown.

    C

    The frequent full checkpoint in a database can cause the overall degradation of the database performance.

    D

    It prompts the Checkpoint （CKPT） process to write data to the data files and redo information to the onlineredo log files


    正确答案： C,B
    解析： 暂无解析

  • 第11题：

    多选题
    You performed the RMAN database backup with the KEEP option.Which two statements are true about this backup?（） (Choose two)
    A

    The KEEP option overrides the configured retention policy

    B

    The KEEP option is an attribute of an individual backup piece

    C

    The backup contains only data files and archived redo log files

    D

    The backup contains data files, the server parameter file and the control file even if the control file auto backup is disabled


    正确答案： B,A
    解析： 暂无解析

  • 第12题：

    多选题
    After performing a clean shut down of the database instance for maintenance， you mount thedatabase and then execute a command to open the database： SQL> ALTER DATABASE OPEN；  Which two statements are true（）
    A

    The online redo log files and online data files are opened.

    B

    All the online data file headers are checked for consistency.

    C

    Instance recovery is performed before opening the database.

    D

    The path and existence of all the log file members are checked


    正确答案： D,C
    解析： 暂无解析

  • 第13题：

    After performing a clean shut down of the database instance for maintenance， you mount the database andthen execute a command to open the database：SQL> ALTER DATABASE OPEN； Which two statements are true（）

    • A、The online redo log files and online data files are opened.
    • B、All the online data file headers are checked for consistency.
    • C、Instance recovery is performed before opening the database.
    • D、The path and existence of all the log file members are checked

    正确答案:A,B

  • 第14题：

    Which two statements are true about checkpointing（）

    • A、The checkpoint frequency decreases with the smaller redo log file size.
    • B、It ensures that all committed data is written to the data files during normal shutdown.
    • C、The frequent full checkpoint in a database can cause the overall degradation of the database performance.
    • D、It prompts the Checkpoint （CKPT） process to write data to the data files and redo information to the online redo log files.

    正确答案:B,C

  • 第15题：

    The instance abnormally terminates because of a power outage. Which statement is true about redolog files during instance recovery（）

    • A、Inactive and current redo log files are required to accomplish recovery.
    • B、Online and archived redo log files are required to accomplish instance recovery.
    • C、All redo log entries after the last checkpoint are applied from redo log files to data files.
    • D、All redo log entries recorded in the current redo log file until the checkpoint position are applied to datafiles.

    正确答案:C

  • 第16题：

    Your database performance has degraded due to frequent checkpointing. What would you do in this scenario？（）

    • A、make redo log files smaller
    • B、increase the size of the checkpoint file
    • C、make the changes as per the advice given by MTTR Advisor
    • D、make the changes as per the advice given by Checkpoint Advisor

    正确答案:C

  • 第17题：

    Which statement is true regarding checkpoints and recovery？（）

    • A、A checkpoint defines the highest system change number （SCN）.
    • B、All redo entries higher or at the SCN are known to be written to the data files.
    • C、Only the redo records containing SCNs higher then the checkpoint need to be applied during recovery.
    • D、The LOG_CHECKPOINT_INTERVAL initialization parameter specifies the amount of time between incremental checkpoints.

    正确答案:C

  • 第18题：

    单选题
    The instance abnormally terminates because of a power outage. Which statement is true about redolog files during instance recovery（）
    A

    Inactive and current redo log files are required to accomplish recovery.

    B

    Online and archived redo log files are required to accomplish instance recovery.

    C

    All redo log entries after the last checkpoint are applied from redo log files to data files.

    D

    All redo log entries recorded in the current redo log file until the checkpoint position are applied to datafiles.


    正确答案： A
    解析： 暂无解析

  • 第19题：

    多选题
    You performed the RMAN database backup with the KEEP option. Which two statements are true regarding this backup？（）
    A

    The backup contains data files， the server parameter file，and the control file even if the control file  autobackup is disabled.

    B

    The KEEP option overrides the configured retention policy.

    C

    The backup contains only data files and archived redo log files.

    D

    The KEEP option is an attribute of an individual backup piece.


    正确答案： A,B
    解析： 暂无解析

  • 第20题：

    多选题
    Which two statements about the background process of the database writer are true（）
    A

    It is possible to have multiple database writers in an Oracle instance.

    B

    It writes dirty buffers， if any， to data files whenever a checkpoint occurs.

    C

    It writes dirty buffers， if any， to data files whenever a transaction commits.

    D

    It writes dirty buffers， if any， to data files before the log writer （LGWR） writes


    正确答案： A,D
    解析： 暂无解析

  • 第21题：

    单选题
    You issued the following commands to configure setting in RMAN; Then you issued the following command to take the backup: RMAN> BACKUP DATABASE PLUS ARCHIVELOG; Which statement is true about the execution of the above command?（）
    A

    The backup will terminate because the FORMAT clause was not configured for the channel

    B

    It backs up two copies of data files to tape and disk, and two copies of archived log file on tape

    C

    It backs up the data files and archived log files to disk, making two copies of each data file and archived log file

    D

    It backs up the data files and archived log files to tape, making two copies of each data file and archived log file


    正确答案： D
    解析： 暂无解析

  • 第22题：

    单选题
    The instance abnormally terminates because of a power outage.  Which statement is true about redo log filesduring instance recovery（）
    A

    Inactive and current redo log files are required to accomplish recovery.

    B

    Online and archived redo log files are required to accomplish instance recovery.

    C

    All redo log entries after the last checkpoint are applied from redo log files to data files.

    D

    All redo log entries recorded in the current redo log file until the checkpoint position are applied to data files


    正确答案： C
    解析： 暂无解析

  • 第23题：

    多选题
    Which two statements about the background process of thedatabase writerare true（）
    A

    It is possible to have multiple database writers in an Oracle instance.

    B

    It writes dirty buffers， if any， to data files whenever a checkpoint occurs.

    C

    It writes dirty buffers， if any， to data files whenever a transaction commits.

    D

    It writes dirty buffers， if any， to data files before the log writer （LGWR） writes.


    正确答案： C,B
    解析： 数据库写进程(DBWn) 可以将缓冲区的内容写入数据文件。DBWn进程负责将数据库缓冲区高速缓存中经过修改的缓冲区（脏数据缓冲区）写入磁盘。虽然对于大多数系统来说，一个数据库写进程(DBW0) 已经足够，但如果系统需要频繁修改数据，则可以配置附加进程（DBW1到DBW9以及DBWa到DBWj）以改进写性能（A正确，可以有很多个dbwr进程）。这些附加DBWn进程在单处理器系统中没有用。 
    当数据库缓冲区高速缓存中的某个缓冲区被修改时，系统会将其标记为脏数据缓冲区，并将其添加到按SCN 顺序存放的灰数据缓冲区的LRUW（LRU 写）列表中。因此，该顺序与为这些更改的缓冲区写入重做日志的重做操作的顺序相匹配。当缓冲区高速缓存中的可用缓冲区的数量低于某个内部阈值（达到服务器进程发现很难获取可用缓冲区的程度）时，DBWn会将灰数据缓冲区写入数据文件，写入顺序与按照LRUW 列表的顺序修改灰数据缓冲区的顺序相同。 SGA 包含的内存结构具有重做流中的某个位置的重做字节地址(RBA)，当实例发生故障时，将从该位置开始恢复。此结构充当指向重做的指针，并且由CKPT 进程按照每三秒一次的频率写入控制文件。由于DBWn按照SCN 顺序写入灰数据缓冲区，而重做按照SCN 顺序执行，因此每当DBWn从LRUW 列表写脏数据缓冲区时，还会将SGA 内存结构中保持的指针前移，以便实例恢复（如果需要）从近似正确的位置开始读取重做，并避免不需要的I/O。这称为―增量检查点‖。 
    注：还有其它一些DBWn可能会执行写操作的情况，例如，当表空间被设置为只读或被置于脱机状态时。在这些情况下，不会出现增量检查点，因为仅属于相应数据文件的灰数据缓冲区在写入数据库时的顺序与SCN 顺序无关。 
    LRU 算法将更频繁访问的块保存在缓冲区高速缓存中，这样，在将缓冲区写入磁盘时，缓冲区不大可能包含将很快有用的数据。 
    DB_WRITER_PROCESSES初始化参数指定DBWn进程数。DBWn进程的最大数目为20。 
    如果用户在启动过程中未指定该进程数，Oracle DB 将根据CPU 和处理器组的数量来决定如何设置DB_WRITER_PROCESSES。 
    在以下情况下，DBWn进程将脏数据缓冲区写入磁盘： 
    • 当服务器进程在扫描阈值数目的缓冲区之后找不到干净的可重用缓冲区时，通知DBWn执行写操作。DBWn在执行其它处理的同时，将灰数据缓冲区异步写入磁盘。 
    •DBWn定期写缓冲区以推进检查点。检查点是重做线程（日志）中开始执行实例恢复的位置。该日志位置由缓冲区高速缓存中最旧的脏数据缓冲区确定。 
    在所有情况下，DBWn均执行成批（多块）写操作以提高效率。多块写操作中写入的块数因操作系统而异。 C答案：是LGWR进程 
    D答案：LGWR先记，DBWR后写。 
    LGWR 的写入速度通常足够快，可以确保缓冲区中始终有空间可供新条目使用，即使对重做日志的访问量很大时也是如此。LGWR 将缓冲区的一个连续部分写入磁盘。 LGWR 在以下情况下执行写操作： • 用户进程提交事务处理时 
    • 重做日志缓冲区的三分之一已满时 • 重做日志缓冲区达到1M的redo条目 
    • 在DBWn进程将经过修改的缓冲区写入磁盘（如果需要）之前 • 每隔3 秒 
    必须在与缓冲区更改相关联的所有重做记录写入磁盘后，DBWn才可以向磁盘写入经过修改的缓冲区（先行写协议）。

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