SQL Query Performance Tuning: Resolving High CPU Usage

So, you were convinced your database has been working efficiently. But one fine day (or late at night), you find your CPU usage surged and reached a hundred percent, leaving you scrambling to find ways to fix it.


This post explains the steps you can take to locate the root cause and resolve this issue, before you begin MYSQL SQL query performance tuning.


How to Get Rid of this Problem in Your Database

Consider the following steps to reduce CPU usage and return things to normal -

Step 1: Uncover the Reason of the Problem


To figure out what went wrong, make sure you enable the slow query log function. Doing this will bring every slow log query into focus, depending on a user-defined threshold. You can later check the logs that contain all of these slow queries and zero-in on the ones causing this issue in particular.

Once you have some information, it’s time to begin your examination, with the help of a few questions, such as:

  • When did this problem begin?

  • Has there been a large traffic boost?

  • Have you released a new feature lately?

  • Has there been any recent change that could have done this? For instance, any changes to the database configuration parameters or the infrastructure?

Step 2: Resolve the Performance Problem


There could be several causes behind the abrupt increase in CPU usage. Given below are a few tips to help you resolve it:

    • Find out more details about the logged in MySQL users, as there could be one or more new users hammering the database.

    • Turn off persistent connections in case they are not entirely required.

    • Analyze the slow statements for new queries or old queries that have suddenly gotten slow.

    • Perform SQL tuning for MySQL for those statements.

    • Note down all of the database processes and look for a deadlock by checking the InnoDB engine status.

    • Analyze database configuration parameters, such as buffer pool size, table and query cache.

    • Verify InnoDB status and search for any processes that are taking up CPU.

Step 3: Prevent it from Occurring Again


The next step is to make sure you’re not caught off guard again with a high CPU utilization problem. For this, you may consider installing a database monitoring solution that can alert you before things seem to get out of hand and help you with SQL query performance tuning.

Such tools work automatically, accumulating several signals to give the user AI enabled MySQL insights, including -

  • Determining newly entered slow queries

  • Arranging queries to be optimized as per priority

  • Uncovering absent and redundant indexes

  • Optimizing queries automatically

  • and many other tasks

In Conclusion


You can easily avoid process related situations that result in a hundred percent CPU usage. With a decent database monitoring software, however, you can receive notifications the second CPU usage begins increasing and perform SQL tuning for Oracle.


The moment you know, you can look for and start applying solutions to resolve this issue within a few minutes. This saves you from the need to hire costly services from database consultants.