151、See the Exhibit.
Which statements are true regarding the USERS tablespace? (Choose all that apply.) A. A bitmap is used to record free extents B. Free extents information is managed within the tablespace C. Free extents information is managed in the SYSAUX tablespace D. The data dictionary tables are updated when extents are allocated or deallocated
Answer: AB
段空间管理：
自动
在数据文件头用位图方式管理文件内分区使用情况
手动
152、
152.Examine the values for the following initialization parameters: FAST_START_MTTR_TARGET=0 LOG_CHECKPOINT_INTERVAL=0 Which two will be the implications of these values in your database? (Choose two.) A. The SGA advisor will be disabled B. The MTTR advisor will be disabled C. Automatic checkpoint tuning will be disabled D. Checkpoint information will not be written to the alert log file
Answer: BC FAST_START_MTTR_TARGET是指允许DBA指定数据库进行崩溃恢复需要的秒数。默认值为0，范围0-3600秒 MTTR（mean time to restoration）指平均恢复时间。 log_checkpoint_interval设定了恢复过程中将要被读的重做记录的数目 FAST_START_MTTR_TARGET参数显式设置为0会禁用MTTR 指导 快速启动检查点功能是通过指定所需的非零恢复平均时间（MTTR）值来启用的，该值将用于设置FAST_START_MTTR_TARGET初始化参数。启用快速启动检查点功能时，oracle将自动保持检查点的速度，以便达到请求的MTTR.如果将该值设置为0，将禁用此功能。
153、
153.In your database instance, the STATISTICS_LEVEL initialization parameter is set to BASIC. What is the impact of this setting? A. Optimizer statistics are collected automatically. B. Only timed operating system (OS) statistics and plan execution statistics are collected. C. The snapshots for the Automatic Workload Repository (AWR) are not generated automatically. D. Snapshots cannot be collected manually by using the DBMS_WORKLOAD_REPOSITORY package. E. The Oracle server dynamically generates the necessary statistics on tables as part of query optimization.
Answer: C
154、
154.You have recently collected statistics on certain objects of a schema in your database. But you observe suboptimal execution plans for the queries on these objects after two days of statistics collection. The optimizer statistics retention period is set to its default value. Which action would help to use the previous set of statistics on the objects? A. Restore statistics from statistics history. B. Reduce the optimizer statistics retention period by 2 days. C. Set the OPTIMIZER_PENDING_STATISTICS parameter to TRUE. D. Reduce the Automatic Workload Repository (AWR) retention period by 2 days.
Answer: A
155、
155.Which three statements regarding the server parameter file (SPFILE) are true? (Choose three.) A. An SPFILE is a binary file B. An SPFILE cannot reside on a client C. An SPFILE cannot contain static parameters D. An SPFILE can store changes persistently across instance restarts E. An SPFILE can be read by the database server, but it is not written to by the server F. An SPFILE must be created manually, before creating a database, even if you use the Database Configuration Assistant (DBCA) to create the database
Answer: ABD