SQL Plan Management Oracle- All Fundamentals You Must Know

While you make any changes in the system parameters or upgrade the Oracle database, you will often notice some highly regressed SQL performance or queries. In such cases, you don’t have to panic because it is quite obvious and happens with many whenever any plan gets changed. But the question is- how will you overcome such a nightmare? Well, it’s not that hard. You can use SQL plan management Oracle. 

In case you don’t have any idea about what it is and how it could be of any help, then we are in the right place. In this blog, we will be covering every basic aspect associated with the SQL plan management and will know how it is useful in preventing query regression or performance regression. 

SQL Plan Management Oracle- What is It?

A deterrent tool that lets the optimizer to control and handle SQL execution plans automatically is known as the SQL plan management. While doing so, it ensures that only known and verified plans are used by the database. 

SQL plan management uses a mechanism that enables the optimizer to use it for a SQL statement. Such a mechanism is referred to as a SQL plan baseline. It’s a set of accepted plans. A plan is typically known to comprise all information associated with the plan. These consist of a SQL plan identifier, bind values, a set of hints, and an optimizer environment. 

This information is used by the optimizer for reproducing an execution plan. Commonly, the database accepts a plan into the plan baseline only after it has verified and confirmed that the plan performs absolutely well.

In a nutshell, a SQL plan management Oracle is a mechanism to mitigate the risk of query regression when you upgrade to Oracle Database 11g or 12c. 

Primary Elements of SQL Plan Management

Essentially, there are three key components of SQL plan management. They are as follows:

SQL Plan Baseline Capture

This component builds a SQL plan baselines that defines the accepted or trusted execution plan for all relevant SQL statements. If you are sceptical about where you can find the SQL plan baselines, then check the plan history. Plan baselines are usually stored in a plan history in the SQL Management Base. The management base needs to be found in the SYSAUX table space. 

SQL Plan Baseline Selection

SQL plan baseline selection assures that only the accepted execution plans are used by the tool for statements having a SQL plan baseline. Moreover, it guarantees that every new execution plan is tracked in the plan history for a statement. The plan history includes both accepted and non-accepted plans. An unaccepted plan could be either rejected that would be verified but not performingor unverified which is newly found but not verified.

SQL Plan Baseline Evolution

Such a component is meant for assessing all the unverified execution plans for a given statement in the plan history for either to be rejected or accepted. 

So, these are basic components of an SQL plan management. In case you wish to fine-tune SQL queries, then you must get a SQL query optimization tool online. 

What Exactly the SQL Plan Management Does?

SQL plan management oracle limits the SQL performance or query regression because of any plan changes in the database. Secondly, the tool is mainly purposed for adapting to changes gracefully. 

You must note that if an event has caused any irreversible execution plan changes like dropping an index, the SQL plan baseline can’t help in such cases.