Oracle performance tuning: A 5-step process for better results

Oracle performance

Understanding the query’s business purpose is critical before beginning any SQL performance tweaking in Oracle. If it’s unclear why – or even if – the query results are being used, it’s possible that the query doesn’t need to run at all, and deactivating it will result in instant speed gains.

Oracle tuning tips

Tip 1: Keep an eye on wait times. 

​Wait Oracle provides events to help you understand how much time a query spends in the database. Begin your tweaking efforts with the questions that are taking the longest. V$ Views can be used to view real-time performance and session data. If you automate this query and poll every second, you can see patterns over time and focus on the questions that take the longest. If you have the Tuning and Diagnostic Packs and use Oracle Enterprise Edition, you can see the V$ Active Session_History view, which contains an hour’s worth of session data. 

​We advocate keeping track of baseline measurements – after all, you’ll need a point of comparison if you want to enhance your performance. She usually looks at buffer gets to see if she’s making progress in tuning. Tuning the query that requires the most pad will almost always influence other questions. ​

Tip 2: Go over the execution plan again.
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Oracle offers a variety of options for obtaining execution plans. An explanation plan is a guess at what the query will accomplish, and it can be incorrect for various reasons. A cached program displays the actual method utilized by the Optimizer. Knowing how to read these plans allows you to see what the Optimizer is up to. Because Oracle performance versions change, you should become familiar with how the Optimizer handles execution plans with each new release.

Tip 3 – Collect information about the objects
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Take a look at the pricey items when you dig deeper into the query that isn’t performing well. Examine the definitions of tables and the sizes of their segments. Examine data collection – are the statistics up to date, and if not, do they affect the Optimizer’s decisions?

Review index definitions, existing keys, and constraint definitions. Make sure you understand the index’s column order and column selectivity. Make sure the Optimizer can access the index as well.

4th Tip: Locate the Driving Table
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Because your goal is to run the query with the table that provides the minor data, you should always know the size of the actual data sets for each stage in the execution plan. The number of logical reads is reduced as a result. In summary, you learn how to use Joins and Filtering predicates to filter data early rather than later in the query.

Tip 5: Recognize Performance Impediments
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It is a handy list of inadvertent speed bottlenecks that should avoid or delete from queries:

• Cursor processing vs. row-by-row processing 
• Processing in parallel 
• DB links-enabled nested views 
• Wildcards are being abused. 
• Using indexed columns with functions 
• Hints that are hard-coded 
• More complicated expressions 
• Bringing disparate perspectives together 

Instead, here are a few activities you ought to do:

• Instead of using literal variables, use bound variables. 
• If you need to retrieve 5% of the data, use an index. 
• When feasible, use equijoin. 
• Always include a WHERE clause in your query.

About Enteros

Enteros offers a patented database performance management SaaS platform. It proactively identifies root causes of complex business-impacting database scalability and performance issues across a growing number of RDBMS, NoSQL, and machine learning database platforms.