OCP-1Z0-052-V8.02-138题

138. Your database is configured in shared server mode. However, your senior DBA asks you to modify

the value of the PRIVATE_SGA limit in the profile of the users. What could be the reason for this?

A.to limit the User Global Area (UGA) memory allocated to a session from the SGA 

B.to limit the amount of memory to be used for the dispatcher queue of a session in SGA

C.to limit the amount of memory to be used for the request pool in System Global Area (SGA)

D.to control the amount of memory allocated in SGA for the local variables for each shared server process

Answer: A  

答案解析：

Limiting Memory Use for Each User Session by Setting PRIVATE_SGA

You can set the PRIVATE_SGA resource limit to restrict the memory used by each client session from the SGA. PRIVATE_SGA defines the number of bytes of memory used from the SGA by a session. However, this parameter is used rarely, because most DBAs do not limit SGA consumption on a user-by-user basis.

The UGA must be available to a database session for the life of the session. For this reason, the UGA cannot be stored in the PGA when using a shared server connection because the PGA is specific to a single process. Therefore, the UGA is stored in the SGA when using shared server connections, enabling any shared server process access to it. When using a dedicated server connection, the UGA is stored in the PGA.

PRIVATE_SGA

Use this clause to apply a weight to the PRIVATE_SGA resource. This limit applies only if you are using shared server architecture and allocating private space in the SGA for your session.