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Oracle 11G OCP 1Z0-053 165

原创 Oracle 作者:LuiseDalian 时间:2014-08-28 17:01:51 0 删除 编辑
(165)View the Exhibit exhibit1.



In the CUSTOMERS_OBE table,when the value of CUST_STATE_PROVINCE is "CA", the value of COUNTRY_ID is "US."

View the Exhibit exhibit2 to examine the commands and query plans.

The optimizer can sense 8 rows instead of 29 rows,which is the actual number of rows in the table.

What can you do to make the optimizer detect the actual selectivity?

A. Change the STALE_PERCENT value for the CUSTOMERS_OBE table.

B. Set the STATISTICS_LEVEL parameter to TYPICAL.

C. Create extended statistics for the CUST_STATE_PROVINCE and CUSTOMERS_OBE.COUNTRY_ID columns.

D. Set the OPTIMIZER_USE_PENDING_STATISTICS parameter to FALSE.


答案:(C)

解析:

需要收集CUST_STATE_PROVINCE和CUSTOMERS_OBE两列组合的数值分布的扩展统计信息


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