Examine the parameter for your database instance:
You generated the execution plan for the following query in the plan table and noticed that the nested loop join was done. After actual execution of the query, you notice that the hash join was done in the execution plan:
Identify the reason why the optimizer chose different execution plans.（）

多项选择题You notice a performance change in your production Oracle database and you want to know which change has made this performance difference. You generate the Compare Period Automatic Database Diagnostic Monitor (ADDM) report to further investigation. Which three findings would you get from the report?（）

A. It detects any configuration change that caused a performance difference in both time periods.
B. It identifies any workload change that caused a performance difference in both time periods.
C. It detects the top wait events causing performance degradation.
D. It shows the resource usage for CPU, memory, and I/O in both time periods.
E. It shows the difference in the size of memory pools in both time periods.
F. It gives information about statistics collection in both time periods.

单项选择题Examine the following query output: You issue the following command to import tables into the hr schema: $ > impdp hr hr directory = dumpdir dumpfile = hr_new.dmp schemas=hr TRANSFORM=DISABLE_ARCHIVE_LOGGING: Y Which statement is true?（）

A. All database operations performed by the impdp command are logged.
B. Only CREATE INDEX and CREATE TABLE statements generated by the import are logged.
C. Only CREATE TABLE and ALTER TABLE statements generated by the import are logged.
D. None of the operations against the master table used by Oracle Data Pump to coordinate its activities are logged.

多项选择题An administrator account is granted the CREATE SESSION and SET CONTAINER system privileges. A multitenant container database (CDB) instant has the following parameter set: THREADED_EXECUTION = FALSE Which four statements are true about this administrator establishing connections to root in a CDB that has been opened in read only mode?（）

A. You can conned as a common user by using the connect statement.
B. You can connect as a local user by using the connect statement.
C. You can connect by using easy connect.
D. You can connect by using OS authentication.
E. You can connect by using a Net Service name.
F. You can connect as a local user by using the SET CONTAINER statement.

单项选择题Your database supports an online transaction processing (OLTP) application. The application is undergoing some major schema changes, such as addition of new indexes and materialized views. You want to check the impact of these changes on workload performance. What should you use to achieve this?（）

A. Database replay
B. SQL Tuning Advisor
C. SQL Access Advisor
D. SQL Performance Analyzer
E. Automatic Workload Repository compare reports

单项选择题You are about to plug a multi-terabyte non-CDB into an existing multitenant container database (CDB). The characteristics of the non-CDB are as follows: -Version: Oracle Database 11g Release 2 (11.2.0.2.0) 64-bit -Character set: AL32UTF8 -National character set: AL16UTF16 -O S: Oracle Linux 6 64-bit The characteristics of the CDB are as follows: -Version: Oracle Database 12c Release 1 64-bit -Character Set: AL32UTF8 -National character set: AL16UTF16 -O S: Oracle Linux 6 64-bit Which technique should you use to minimize down time while plugging this non-CDB into the CDB?（）

A. Transportable database
B. Transportable tablespace
C. Data Pump full export/import
D. The DBMS_PDB package
E. RMAN