odelia - 2008-10-9 15:56:00
1 You executed the following SQL statement to change the goal of the cost-based optimizer (CBO): What will be the result of this statement? A.The goal of the CBO for the current session is set to best throughput. B.The optimizer uses a cost-based approach for all SQL statements in the session
provided the statistics are available. C.It will result in an error because the goal of the CBO cannot be changed at the session level. D.The goal of the CBO for the current session is set to find the best plan for fast delivery of all the rows while using a mix of cost and heuristics. ANSWER: A 9i DBA 1z0-033 考試題庫由我們的資深IT認證講師及產品專家精心打造，包括了當前最新的全套全真1z0-033考試試題，全部附有正確答案。所有購買本站認證考題的客戶都將得到60天的免費升級服務，保證了對Oracle9i Database:Performance Tuning考試題庫的完整覆蓋。 助妳壹次通過 Oracle9i Database:Performance Tuning 認證考試，壹次不過全額退款！Oracle9i Database:Performance Tuning 題庫根據廠家考試的變化動態更新，在廠家考題每次發生變化後，我們承諾2天內更新 Oracle9i Database:Performance Tuning 題庫。確保 Oracle9i Database:Performance Tuning 考題的覆蓋率始終都在96％以上。2. Which two statements are true regarding the statistics used by the optimizer to
generate an optimal plan? (Choose two.) A.The statistics collected through a histogram are not useful for better selectivity estimates of unevenly distributed data. B.Dynamic sampling is preferred when the cost of collecting the sample statistics outweighs the advantage of a better execution plan. C.The maximum and minimum values collected by the column statistics leads to an optimal plan if there is an even distribution of data between those two values. D.The statistics collected through a histogram are useful if the data distribution is skewed between minimum and maximum values. ANSWER: CD