单项选择题
A. The listener is not running on the database node.
B. The TNS_ADMIN environment variable is set to the wrong value.
C. The orcl.oracle.com database service is not registered with the listener.
D. The DEFAULT_DOMAIN parameter is set to the wrong value in the sqlnet.ora file.
E. The listener is running on a different port.
单项选择题 In your multitenant container database (CDB) containing pluggable databases (PDB), users complain about performance degradation. How does real-time Automatic database Diagnostic Monitor (ADDM) check performance degradation and provide solutions?（）
多项选择题 You plan to use the In Database Archiving feature of Oracle Database 12c, and store rows that are inactive for over three months, in Hybrid Columnar Compressed (HCC) format. Which three storage options support the use of HCC?（）
单项选择题 You notice that the performance of your production 24/7 Oracle database significantly degraded.Sometimes you are not able to connect to the instance because it hangs. You do not want to restart thedatabase instance.How can you detect the cause of the degraded performance?（）