This preview shows page 1. Sign up to view the full content.
Unformatted text preview: egories.
B. You can only have one stored outline per SQL statement.
C. Plan stability works only when SQL statements match.
D. Stored outlines are saved in the data dictionary (SYS schema)
E. Stored outlines become invalid when you analyze the associated objects.
Answer: A, C
You can group outlines in categories. To use stored outlines you also need to be sure that SQL
statements match textually.
Reference: Here is explanation about 'plan stability' from Metalink:
Oracle9i Database Performance Tuning Guide and Reference
Release 2 (9.2)
Part Number A96533-02
Chapter 7 "Using Plan Stability"
"Plan stability prevents certain database environment changes from affecting the
performance characteristics of applications. Such changes include changes in
optimizer statistics, changes to the optimizer mode settings, and changes to
parameters affecting the sizes of memory structures, such as SORT_AREA_SIZE and
Actualtests.com - The Power of Knowing 1Z0-024
BITMAP_MERGE_AREA_SIZE. Plan stability is most useful when you cannot risk any
performance changes in an application.
Plan stability preserves execution plans in stored outlines. Oracle can create a
public or private stored outline for one or all SQL statements. The optimizer then
generates equivalent execution plans from the outlines when you enable the use of
stored outlines. You can group outlines into categories and control which category of
outlines Oracle uses to simplify outline administration and deployment.
The plans Oracle maintains in stored outlines remain consistent despite changes to
a system's configuration or statistics. Using stored outlines also stabilizes the
generated execution plan if the optimizer changes in subsequent Oracle releases.
Plan stability also facilitates migration from the rule-based optimizer to the cost-based
optimizer when you upgrade to a new Oracle release."
B: It can be more than one stored outline per SQL statement.
D: Stored outlines are saved in the OUTLN schema,...
View Full Document
- Fall '09