The MySQL Devroom is pleased to announce the committee that will decide on the talks to be presented for this totally new format of the next FOSDEM edition. Indeed, if you are not yet aware of it, FOSDEM 2021 will be an online event. Every year we are overwhelmed with submissions and it’s the committee that has the thankless task of deciding on the final selections and agenda.

Every year, we try to have a mix of experienced members knowing the process of the devroom talks rating and expect them to mentor the new members.

This year’s committee members are:

• Elisa Usai
• Gabriela D’Ávila Ferrara
• Liz Van Dijk
• Silvia …

Recently (earlier today), I blogged about how to use PHPMyAdmin with a MDS instance. I also showed at the end of the video that it’s possible to open MySQL Router on the compute instance to connect from anywhere. However this has security risks of course. Therefor, it’s not recommended.

If you want to connect from on-premise to your MDS instance you should use a VPN or a SSH tunnel. Take a look at these previous post:

• https://lefred.be/content/migrate-from-on-premise-mysql-to-mysql-database-service/
• …

I recently received several messages from developers not being comfortable with command line when they need to create schemas, tables, … They were asking me for an easy alternative when testing MDS.

There is a very popular tool in the developer community to manage their databases in MySQL: PHPMyAdmin.

So if you are trying MDS (MySQL Database Service in Oracle Cloud Infrastructure), it’s possible to deploy such instance with a compute instance hosting PHPMyAdmin very easily using OCI’s Resource Manager and a stack (zip file) that you can find here: https://github.com/lefred/oci-phpmyadmin-mds/releases/tag/1.1.0

If you want to try MDS in OCI, you can get free credits using this url: …

We are happy to inform you know about regular MySQL Webinars run by Carsten Thalheimer, the MySQL Solution Engineer. They are scheduled once a month and they are fully virtual. See details below:

• In English:
  • Timing: every first Thursday of a month
  • Focus: English speaking audience (focus Middle East)
  • Webinar Title: Things I should have known before I installed MySQL... 
  • URL for Zoom: https://oracle.zoom.us/webinar/register/WN_uMez9v1dQfiw7WucMyuxXw
• In German
  • Timing: every first Friday of a month
  • Focus: German speaking audience (focus D-A-CH)
  • Webinar Title: Things I should have known before I installed MySQL... …

The benefits of jemalloc versus glibc memory allocator for use with MySQL have been widely discussed. With jemalloc (along with Transparent Huge Pages disabled) there is less memory fragmentation, and thus more efficient resource management of the server memory. For MySQL 5.6, installing jemalloc is enough to enable it when starting the MySQL process. However, for MySQL 5.7 and 8.0.X series, you will need to take a few extra steps.

Enabling jemalloc on Percona Server for MySQL

Installing the jemalloc package is simple for Percona. This is because the library is available on the Percona repository, which is available for both apt and yum package management:

…

If you use SQL on a regular basis, then you are well aware that Window Functions are powerful. They allow us to simplify queries that would otherwise be quite the mess. We can provide meaningful insight across rows of data without collapsing the results into a single value. I have written numerous blog posts on Window Functions, many here recently. I decided to make this blog post a compilation of all the Window Function posts I have written, providing a one-stop source for any readers interested in learning more about Window Functions…

Image by Free-Photos from …

The tables in PERFORMANCE_SCHEMA (P_S) are not actually tables. You should not think of them as tables, even if your SQL works on them. You should not JOIN them, and you should not GROUP or ORDER BY them.

Unlocked memory buffers without indexes

The stuff in P_S has been created with “keep the impact on production small” in mind. That is, from a users point of view, you can think of them as unlocked memory buffers – the values in there change as you look at them, and there are precisely zero stability guarantees.

There are also no indexes.

Unstable comparisons

When sorting a table for a GROUP BY or ORDER BY, it may be necessary to compare the value of one row to other rows multiple times in order to determine where the row goes. The value compared to other rows can change while this happens, and will change more often the more load the server has. The end …

I am pretty new on the Oracle Cloud Infrastructure technology, so maybe I am talking about something you already know. But anyway I prefer to share this case: it can help if you encounter the same problem as me. Let’s take the risk to have too much information rather than nothing!

The problem

I was doing some tests on the new MySQL Database Service and during the setup I decided to generate my ssh keys via the OCI console:

When I tried to connect via PuTTY or MobaXterm to my compute instance using the opc account and my private key (generated previously), I got the following …

I am pretty new on the Oracle Cloud Infrastructure technology, so maybe I am talking about something you already know. But anyway I prefer to share this case: it can help if you encounter the same problem as me. Let’s take the risk to have too much information rather than nothing!

The problem

I was doing some tests on the new MySQL Database Service and during the setup I decided to generate my ssh keys via the OCI console:

When I tried to connect via PuTTY or MobaXterm to my compute instance using the opc account and my private key (generated previously), I got the …

How scheduler and script stand in supporting failover (Percona and Marco example) 

In part one of this series,  I had illustrated how simple scenarios may fail or have problems when using Galera native support inside ProxySQL. In this post, I will repeat the same tests but using the scheduler option and the external script.

The Scheduler

First a brief explanation about the scheduler.

The scheduler inside ProxySQL was created to allow administrators to extend ProxySQL capabilities. The scheduler gives the option to add any kind of script or application and run it at the specified interval of time. The scheduler was also the initial first way we had to deal with Galera/Percona XtraDB Cluster (PXC) node management in case of issues. 

…