What is SQL plan management?
What is SQL plan management?
SQL Plan Management (SPM) provides a framework for completely transparent controlled execution plan evolution. With SPM the optimizer automatically manages execution plans and ensures only known or verified plans are used.
Which of the following PL SQL package is used to support SQL plan management feature?
|Question ID 22024||Which of the following PL/SQL packages is used to support the SQL plan management feature?|
|Option B||Utl_Com press|
How do I find SQL plan baselines?
Identify the SQL_ID of the SQL statement by querying the V$SQL view. Use this SQL_ID to manually load the SQL plan baseline. The DBA_SQL_PLAN_BASELINES view provides information about the SQL plan baselines. We can see there is a single plan associated with our baseline, which is both enabled and accepted.
What is baseline in Oracle database?
SQL plan management uses a mechanism called a SQL plan baseline. A plan baseline is a set of accepted plans that the optimizer is allowed to use for a SQL statement. In the typical use case, the database accepts a plan into the plan baseline only after verifying that the plan performs well.
How do I fix Oracle execution plan?
How to fix your own SQL plan in Oracle?
- First we need to identified the query.
- Plan control.
- First I need to load the plan from my application query into SPM baseline:
- I have now a new cursor in the SQL view with the SQL_PLAN_BASELINE identifier:
- I can now find the SPM content for my SQL:
What is SQL profile and baseline?
A SQL profile contains auxiliary information that mitigates these problems. SQL plan baselines, on the other hand, constrain the optimizer to only select from a set of accepted plans. The cost-based approach is still used to choose a plan, but only within this set of plans.
What is the difference between SQL profile and SPM baseline?
Difference Between SQL Profiles and SQL Baselines SQL profiles only helps the optimizer to choose the better plan providing some additional stats and information but it does not force the optimizer for any specific plan . Where as the SQL baselines constrain the optimizer to choose from the accepted set of plans.
What is the difference between SQL Profiles and SQL plan baselines?
Think of it this way: SQL profiles give information to the optimizer to help select the best plan but don’t force the optimizer to select any specific plan. SQL plan baselines limit the optimizer plan selection to a set of accepted plans.
What is SQL profile in Oracle 11g?
A SQL profile is a set of auxiliary information specific to a SQL statement. Conceptually, a SQL profile is to a SQL statement what statistics are to a table or index. The database can use the auxiliary information to improve execution plans. Therefore, SQL profiles just guide the optimizer to a better plan.
How do I know if execution plan has changed?
You can check if the SQL execution plan has changed by using the Active Workload Repository (AWR). First, you need to find the SQL_ID for the relevant query. The view GV$SQL contains the most recent SQL. If you can’t find the query in this view, try DBA_HIST_SQLTEXT instead.
Why did the execution plan change?
A plan change can occur due for a variety of reasons including but not limited to the following types of changes occurring in the system: optimizer version, optimizer statistics, optimizer parameters, schema/metadata definitions, system settings, as well as SQL profile creation.