[单选]

An index called ORD_CUSTNAME_IX has been created on the CUSTNAME column in the ORDERS table using the following command:
SQL>CREATE INDEX ord_custname_ix ON orders(custname);
The ORDERS table is frequently queried using the CUSTNAME column in the WHERE clause.
You want to check the impact on the performance of the queries if the index is not available. You do not want the index to be dropped or rebuilt to perform this test.Which is the most efficient method of performing this task?（）

An  administrator  has  a  server  experiencing  performance  problems  with  logical  volumes  within  a particular volume group.  Which command can report I/O statistics for logical partitions with each logicalvolume within the volume group（） Islv。 vmstat。 iostat。 Ivmstat。 下列关于教学目标作用的描述哪一项是错误的？（） 教学目标为教师的教学提供了方向性指导。 教学目标是教学评价的依据。 教学目标可以引导学生的学习活动。 教学目标只对教学过程起指导作用，与教学评价关系不大。 The system administrator has determined that a new JFS log needs to be created on a different disk， in order to decrease an I/O bottleneck. Which of the following steps are the most correct？（）   mklv -t jfslog -y LVname VGname 1 PVname  logform /dev/LVname  chfs -a log=/dev/LVname /filesystemname m ount and unmount filesystem。  mklv -t jfslog -y LVname VGname PVname  unmount filesystem  vi /etc/filesystems， change entry for lv to point filesystem to new JFS log  mount filesystem。  mklvcopy -a jfslog -y LVname VGname 1 PVname  chfs -a log=/dev/LVname /filesystemname  unmount and mount file system。  mklvcopy  -t jfslog -y LVname VGname 1 PVname  logform /dev/LVname  vi /etc/filesystems， change entry for lv to point filesystem to new JFS log  unmount and mount filesystem。 The boot .net.tcp.client fileset is broken. Which of the following procedures must be performed to fix the problem?（） Reinstall with the Force Overwrite option。 Update the fileset at a lower level。 Install the update in the commit state。 Reboot the system to fix the broken filelist。 简述城市生态评价的一般程序。

An index called ORD_CUSTNAME_IX has been created on the CUSTNAME column in the ORDERS table using the following command:
SQL>CREATE INDEX ord_custname_ix ON orders(custname);
The ORDERS table is frequently queried using the CUSTNAME column in the WHERE clause.
You want to check the impact on the performance of the queries if the index is not available. You do not want the index to be dropped or rebuilt to perform this test.Which is the most efficient method of performing this task?（）