What is Oracle SPM?
Table of Contents
What is Oracle SPM?
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.
Where SQL plan is stored in Oracle?
SYSAUX tablespace
SQL plan baselines are stored in the SQL management base in the SYSAUX tablespace. » Plan Selection: » Ensures only accepted execution plans are used for statements with a SQL plan baseline and records any new execution plans found for a statement as unaccepted plans in the SQL plan baseline.
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:
Where SQL plan is stored?
For each submitted T-SQL query, the SQL Server Engine stores the generated plans in a special section of the memory called the Plan cache, to use it whenever the same query is executed again, eliminating the overhead of creating a new SQL Execution Plan for the same query.
What is the difference between SQL profile and SPM baseline?
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 baseline in Oracle?
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.
What is SQL baseline in Oracle?
What is Oracle baseline?
SQL Plan Baselines are a new feature in Oracle Database 11g that helps to prevent repeatedly used SQL statements from regressing because a newly generated execution plan is less effective than what was originally in the library cache.
What is SQL baseline?
What is SQL plan baselines?
How do I create a baseline in SQL?
You can create a SQL plan baseline in several ways: using a SQL Tuning Set (STS); from the cursor cache; exporting from one database and importing into another; and automatically for every statement.
What is difference between SQL profile and SQL baseline in Oracle?
So, SQL profiles provide additional information to the optimizer to help select the best plan; they don’t constrain the optimizer to any specific plan, which is why they can be shared. SQL plan baselines, on the other hand, constrain the optimizer to only select from a set of accepted plans.
