Home » Oracle » 1z0-117 » Which two options would you use for the optimizer?
You are administering a database supporting an OLTP workload where the users perform frequent queries for fetching a new rows as possible, involving join operations on recently inserted data. In addition at night, a few DSS queries are also performed. Examine the initialization parameters for the instance:
Which two options would you use for the optimizer?
A. Set the OPTIMIZER_MODE initialization parameter to FIRST_ROWS_n.
B. Add the hint ALL_ROWS in the DOS queries.
C. Set the OPTIMIZER_INDEX_CACHING initialization parameter to 0.
D. Add a hint INDEX_COMBINE in all DSS queries.
E. Set the OPTIMIZER_INDEX_COST_ADJ initialization parameter to 100.
Correct Answer: AE
Explanation/Reference:
The last appended rows are more likely to be found quickly withFIRST_ROWS_n.
E: Make it not to prioritize index instead if table scan.
OPTIMIZER_INDEX_COST_ADJ
OPTIMIZER_INDEX_COST_ADJ lets you tune optimizer behavior for access path selection to be more or less index friendly—that is, to make the optimizer more or less prone to selecting an index access path over a full table scan.
The default for this parameter is 100 percent, at which the optimizer evaluates index access paths at the regular cost. Any other value makes the optimizer evaluate the access path at that percentage of the regular cost. For example, a setting of 50 makes the index access path look half as expensive as normal.
|
Download Printable PDF. VALID exam to help you PASS.
|
 |
