Oracle认证考试章节练习(2020.01.15)

You set the following parameters in the parameter file and restarted the database：MEMORY_MAX_TARGET=0MEMORY_TARGET=500M
PGA_AGGREGATE_TARGET=90MSGA_TARGET=270M
Which two statements are true about these parameters after the database instance is restarted（）

In your multitenant container database (CDB) containing same pluggable databases (PDBs), you execute the following commands in the root container:
Which two statements are true?（）

Twenty database users are connected to your database. Five of the users are running long queries involving sort operations. The TEMP tablespace is the default temporary tablespace for your database. You are performing offline tablespace backups of individual tablespaces and erroneously execute the following statement：  
SQL>ALTER TABLSPACE temp OFFLINE NORMAL；  
What is the result of this statement？（）

You want to configure the Flashback Database feature and retain flashback logs for three days. 
Presently the database is open and configured in ARCHIVELOG mode. The following steps must be performed in the correct sequence to do this：  
1. Set the retention target： 
SQL> ALTER SYSTEM SET DB_FLASHBACK_RETENTION_TARGET=4320； 
2. Enable Flashback Database： 
SQL> ALTER DATABASE FLASHBACK ON； 
3. Mount the database： 
SQL> STARTUP MOUNT EXCLUSIVE 
4. Shutdown the instance： SQL> SHUTDOWN IMMEDIATE 
5. Open the database： 
SQL> ALTER DATABASE OPEN；  
Choose the correct sequence.（）

Automatic Shared Memory Management is disabled for your database instance. You realize that there arecases of SQL statements performing poorly because of repeated parsing activity， resulting in degradation ofperformance. 
What would be your next step to improve performance（）