OCP-1Z0-053-V12.02-41题

41.You have applications that have frequently executed queries, and produce small and static result sets.

You configure the sqlnet.ora file in the client machine to set a nonzero value for the

OCI_RESULT_CACHE_MAX_SIZE parameter.

What is the purpose of this configuration?

A. to avoid round trips to the server by enabling caching of query results in client memory

B. to improve performance by storing a copy of the data from the private SQL area of the PGA

C. to enhance the query performance by creating a cache in the client memory for sorting operations

D. to avoid the storing of query plans and results in the server by creating a cache in the client memory

Answer: A

答案解析：

参考：http://docs.oracle.com/cd/E11882_01/appdev.112/e10646/oci10new.htm#LNOCI16752

The server initialization parameters:

CLIENT_RESULT_CACHE_SIZE

The default value is zero, implying that the client cache feature is disabled. To enable the client result cache feature, set the size to 32768 bytes (32 Kilobytes (KB)) or greater. This is the minimum size of the client per-process result set cache. All OCI client processes get this minimum size. This can be overridden by the sqlnet.ora configuration parameter OCI_RESULT_CACHE_MAX_SIZE only if this feature is enabled on the server by theCLIENT_RESULT_CACHE_SIZE initialization parameter.

You can view the current default maximum size by displaying the value of the CLIENT_RESULT_CACHE_SIZE parameter. To increase this maximum size, you can set CLIENT_RESULT_CACHE_SIZE. However, because CLIENT_RESULT_CACHE_SIZE is a static parameter, you must include the SCOPE = SPFILE clause if you use an ALTER SYSTEM statement, and you must restart the database before any changes to this parameter take effect.

Note that if the client result cache feature is disabled at the server, the client configuration parameter OCI_RESULT_CACHE_MAX_SIZE is ignored and the client result cache cannot be enabled at the client.

Client Configuration File

A client configuration file is optional and overrides the cache parameters set in the server init.ora initialization file. These parameters are part of a sqlnet.orafile. The following optional parameters are available for client configuration:

• OCI_RESULT_CACHE_MAX_SIZE (optional) - Maximum size in bytes for the per-process query cache. Specifying a size less than 32768 in the client sqlnet.orafile disables the client result cache feature for client processes reading this sqlnet.ora file.