[多选]

You work as a database administrator for Supportcenter.cn. Users in the SupportCenter PROD database complain about the slow response when accessing the database. In the Active Session Waiting： Configuration page you find that the majority of the wait time is for the redo log buffer. Further investigation using the Run Queue graph and operating system tools reveals that the redo log files are on the same disks， and that the disk I/O for the redo log files is the reason for the performance degradation. 
Which two actions would you take to gain performance？（）

简述维持与改善关节活动范围的训练方法的适应证和禁忌证。 Evaluate these two SQL statements: SELECT last_name, salary , hire_date FROM EMPLOYEES ORDER BY salary DESC; SELECT last_name, salary, hire_date FROM EMPLOYEES ORDER BY 2 DESC; What is true about them? （） The two statements produce identical results.。 The second statement returns a syntax error.。 There is no need to specify DESC because the results are sorted in descending order by default.。 The two statements can be made to produce identical results by adding a column alias for the salary column in the second SQL statement.。 An administrator is applying a corrective service to their HMC. The corrective service has been shipped on 3 DVDs. Which action will ensure the corrective service is correctly installed？（）  Examine the following output： SQL> SELECT index_name，status FROM dba_indexes WHERE status=’UNUSABLE’； INDEX_NAME STATUS------------------------------ ----------- EIND UNUSABLE Which two statements about the above index are true（） It is ignored by the query optimizer.。 It is not used while the index is being rebuilt.。 The index cannot be rebuilt， and has to be re-created.。 The index is automatically rebuilt when used the next time。 不能燃烧的永久气体共有（）种。 17。 11。 9。 4。

You work as a database administrator for Supportcenter.cn. Users in the SupportCenter PROD database complain about the slow response when accessing the database. In the Active Session Waiting： Configuration page you find that the majority of the wait time is for the redo log buffer. Further investigation using the Run Queue graph and operating system tools reveals that the redo log files are on the same disks， and that the disk I/O for the redo log files is the reason for the performance degradation. 
Which two actions would you take to gain performance？（）