OCP-1Z0-053-V12.02-61题

 

61.Which of the following advisors within the Oracle advisory framework will analyze a single SQL

statement and make recommendations for performance improvement?

A. SQL Repair Advisor

B. SQL Optimizer

C. SQL Access Advisor

D. SQL Tuning Advisor

Answer: D

答案解析：

参考：http://docs.oracle.com/cd/E11882_01/server.112/e41573/sql_tune.htm#PFGRF02802

SQL优化指导可以对以下任一来源运行该指导：

- Active SQL （活动SQL）：分析当前活动的顶级 SQL 语句

- SQL Tuning Sets（SQL 优化集）：分析用户提供的一组 SQL 语句，You can create a SQL tuning task for a single SQL statement.

- Historical SQL (AWR) （以往的SQL (AWR)）：分析AWR 快照捕获的SQL 语句

Answer option D is correct.

The SQL Tuning Advisor takes one or more SQL statements and performs an analysis to determine what can

be done to improve the performance of the SQL statement(s).

Recommendations include rewriting the SQL statement,adding indexes, or even changing initialization

parameters or memory component sizes such as the SGA size or buffer cache.

The SQL Tuning Advisor is accessed via tools such as Top SQL, the Automatic SQL Tuning Advisor, or the

Top Sessions interface from within EM. In contrast, the SQL Access Advisor takes a broader view of SQL

tuning. It considers a larger subset of SQL statements, such as all SQL statements run within a specified time

period or from a SQL Tuning Set (STS). The SQL Access advisor may recommend additional indexes as well

as materialized views to improve performance.

The SQL Repair Advisor analyzes a SQL statement that causes a critical error and records the results in the

Automatic Diagnostic Repository (ADR). It may recommend a patch to fix the problem, or may provide an

alternate execution plan to avoid causing an error in the future.

Other advisors within the advisory framework include memory advisors that monitor usage of the SGA and

PGA and recommend optimal settings for these memory structures including the substructures within them,

such as the library cache and the large pool.

Answer option A is incorrect. The SQL Repair Advisor only makes recommendations for SQL statements that

cause a critical error in the ADR.

Answer option B is incorrect. There is no such advisor such as the SQL Optimizer, although the Oracle

optimizer uses statistics to determine the best execution plan.

Answer option C is incorrect. The SQL Access Advisor analyzes groups of SQL statements that run during the

same time period, not one or two SQL statements in isolation as the SQL Tuning Advisor does.