I was recently faced with a real issue about completely exhausting the disk space on MySQL. This was a serious issue because of the continuous outages of the service, as the customer had to constantly restart the server and wait for the next outage.

What was happening? In this article, I’m going to explain it and propose solutions.

Implicit temporary tables

MySQL needs to create implicit temporary tables for solving some kinds of queries. The queries that require a sorting stage most of the time need to rely on a temporary table. For example, when you use GROUP BY, ORDER BY or DISTINCT.  Such queries are executed in two stages: the first is to gather the data and put them into a temporary table, the second is to execute the sorting on the temporary table.

A temporary table is also needed in case of some UNION statements evaluation, for …

Please join Percona’s Principal Support Engineer Sveta Smirnova as she presents Billion Goods in Few Categories: How Histograms Save a Life?

Watch the Recorded Webinar

We store data with the intention to use it: search, retrieve, group, sort, etc. To perform these actions effectively, MySQL storage engines index data and communicate statistics with the Optimizer when it compiles a query execution plan. This approach works perfectly well unless your data distribution is uneven.

Last year I worked on several tickets where data followed …

Sysbench has long been established as the de facto standard when it comes to benchmarking MySQL performance. Percona relies on it daily, and even Oracle uses it when blogging about new features in MySQL 8. Sysbench comes with several pre-defined benchmarking tests. These tests are written in an easy-to-understand scripting language called Lua. Some of these tests are called: oltp_read_write, oltp_point_select, tpcc, oltp_insert. There are over ten such scripts to emulate various behaviors found in standard OLTP applications.

But what if your application does not fit the pattern of traditional OLTP? How can you continue to utilize the power of load-testing, benchmarking, …

Python 2 reaches EOL on 2020-01-01 and one of its commonly used third-party packages is MySQL-python. If you have not yet migrated away from both of these, since MySQL-python does not support Python 3, then you may have come across some issues if you are using more recent versions of MySQL and are enforcing a secured installation. This post will look at two specific issues that you may come across (caching_sha2_password in MySQL 8.0 and TLSv1.2 with MySQL >=5.7.10 when using OpenSSL) that will prevent you from connecting to a MySQL database and buy …

In this blog, I will provide answers to the Q & A for the MySQL 8.0 Architecture and Enhancement webinar.

First, I want to thank everybody for attending my April 9, 2019, webinar. The recording and slides are available here. Below is the list of your questions that I was unable to answer fully during the webinar.

Q: What kind of Encryption levels does MySQL 8.0 provide?

The MySQL data-at-rest encryption feature supports the Advanced Encryption Standard (AES) block-based encryption algorithm and aes_256_cbc encryption algorithm for data at rest is hard coded.

Q: At what frequency does the redo log buffer flush the changes to disk? When is the commit variable set to zero?

…

Please join Percona’s Product Manager, Michael Coburn, as he presents his talk Extending and Customizing Percona Monitoring and Management on April 10th, 2019 at 10:00 AM PDT (UTC-7) / 1:00 PM EDT (UTC-4).

Register Now

Do you already run stock PMM in your environment and want to learn how you extend the PMM platform? If so, come learn about:

1. Dashboard Customizations
* How to create a custom dashboard from existing graphs, or build Cross Server Dashboards
2. External Exporters – Monitor any service, anywhere!
* …

Please join Percona’s Bug Analyst, Lalit Choudhary as he presents his talk MySQL 8.0 Architecture and Enhancement on Tuesday, April 9th, 2019 at 6:00 AM PDT (UTC-7) / 9:00 AM EDT (UTC-4).

Register Now

The release of MySQL 8.0 offers much more to users compared to previous releases. There are major changes in architecture as well as adding differentiating features, and improvements to manage the database more efficiently.

In our talk we will go through, MySQL 8.0 …

Please join Percona’s Principal Support Engineer, Sveta Smirnova, as she presents MySQL Performance Schema in 1 hour on Thursday, March 21st, 2019, at 10:00 am PDT (UTC-7) / 1:00 pm EDT (UTC-4).

Register Now

MySQL 8.0 Performance Schema is a mature tool, used by humans and monitoring products. It was born in 2010 as “a feature for monitoring server execution at a low level.” The tool has grown over the years with performance fixes and DBA-faced features. In this webinar, I will give …

Please join Percona’s Information Security Architect, David Bubsy, as he presents his talk Web Application Security – Why You Should Review Yours on March 14th, 2019 at 6:00 AM PDT (UTC-7) / 9:00 AM EDT (UTC-4).

Register Now

In this talk, we take a look at the whole stack and I don’t just mean LAMP.

We’ll cover what an attack surface is and some areas you may look to in order to ensure that you can reduce it.

For instance, what’s an attack surface?

Acronym Hell, what do they mean?

…

Join Percona Support Engineer, Vinicius Grippa, as he presents his talk Enhancing MySQL Security on Thursday, March 7th, 2019 at 7:00 AM PST (UTC-8) / 10:00 AM EST (UTC-5).

Register Now

Security is always a challenge when it comes to data. What’s more, regulations like GDPR add a whole new layer on top of it, with rules more and more restrictive to access and manipulate data. Join us in this presentation to check security best practices, as well as traditional and new features available for MySQL including features coming with the new …