I recently troubleshoot an interesting MySQL crash, and I think it is worth sharing (with the related bugs). MySQL crashed when the disk was full, you can see the free disk graph below. The Y-axis is in the tens of GiB scale and the X-axis is in the hour scale. Can you guess what happened ?
Just to make sure we agree on the meaning of the graph above, let's describe it
Introduction In this article, I’m going to show you how to optimize the queries executed by a Spring application running on MySQL using Releem. For a short introduction about Releem, check out this previous article, in which I explained how to set up Releem to collect metrics from your MySQL database. Spring Petclinic application The application under test is going to be the well-known Spring Petclinic that we are going to run using the MySQL profile: After starting the application, we are going to run the petclinic_test_plan.jmx JMeter test plan that is... Read More
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In the last weeks / months, I have been working on understanding / improving MySQL startup with many tables. I already wrote five posts on the subject, they are listed below. In this post, I use the knowledge we gained in the previous two posts to show the interest of tuning InnoDB Tablespace Duplicate Check Threads, making startup 30% in one case (2:28 vs. 3:33) and 5% in
In the last weeks / months, I have been working on understanding / improving MySQL startup with many tables. I already wrote four posts on the subject, they are listed below. In this post, I use the system analysis of the previous post to revisit the light optimization on EBS volumes. With this analysis, I am able to determine why the previous tests did not show
This post is a little long, please bear with me as after the intro, you can skip to the essential.In the last weeks / months, I have been working on understanding / improving MySQL startup with many tables. I already wrote three posts on the subject, they are listed below. In this post, I focus on describing the startup phase InnoDB Tablespace Duplicate Check (Duplicate Check for
In the last weeks / months, I have been working on understanding / improving MySQL startup with many tables. I already wrote two posts on the subject, the links are below. So far, I did not share what brought my attention to this, and it is the subject of this post. Also, and because it is related, I come back to the optimization / contribution I already made on
Explore the powerful features of Aurora Serverless V2 for MySQL in this informative blog series. Learn about read-only scaling, parameter support, and cost performance. Compare costs between Provisioned Aurora and Aurora Serverless V2. Discover key takeaways for optimizing your MySQL deployment on the cloud. Read now!
[Read more]Sometimes, the MySQL Optimizer chooses a wrong plan, and a query that should execute in less than 0.1 second ends-up running for 12 minutes ! This is not a new problem: bugs about this can be traced back to 2014, and a blog post on the subject dates of 2015. But even if this is old news, because this problem recently came to my attention, it is a problem worth writing on.
This
Introduction In this article, we are going to see how we can enable the MySQL JDBC Driver Statement Caching mechanism, which, unfortunately, is not enabled by default. No matter what data access framework you are using, you still need to configure the JDBC Driver if you want to get the most out of the MySQL database engine. MySQL JDBC client-side PreparedStatement As I explained in this article, by default, the MySQL JDBC Driver emulates prepared statements. So, no matter if you are executing a plain Statement or a PreparedStatement, the SQL statement... Read More
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In MySQL 8.0.16 the optimizer has improved again! Comparisons of columns of numeric types with constant values are checked and folded or removed for invalid or out-of-rage values. The goal is to speed up query execution.