The release of MySQL 8.0 has brought a lot of bold implementations that touched on things that have been avoided before, such as added support for common table expressions and window functions. Another example is the change in how AUTO_INCREMENT (autoinc) sequences are persisted, and thus replicated.

This new implementation carries the fix for bug #73563 (Replace result in auto_increment value less or equal than max value in row-based), which we’ve only found about recently. The surprising part is that the use case we were analyzing is a somewhat common one; this must be affecting a good number of people out there.

Understanding the bug

The business logic of the use case is such the UNIQUE column found in a table whose id is managed by an AUTO_INCREMENT sequence needs to be updated, and this is done with a …

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The traditional way to monitor replication in MySQL is the SHOW SLAVE STATUS command. However as it will be shown, it has its limitations and in MySQL 5.7 and 8.0 the MySQL developers have started to implement the information as Performance Schema tables. This has several advantages including better monitoring of the replication delay in MySQL 8.0. This blog discusses why SHOW SLAVE STATUS should be replaced with the Performance Schema tables.

The Setup

The replication setup that will be used for the examples in this blog can be seen in the following figure.

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There are multiple way to setup replication with MySQL 8.0 and our replication offer as never been so rich: asynchronous, semi-synchronous, group replication, multi-source, … and much more options !

But if you want to setup a very quick Master-Slave environment from scratch for a quick test (you can always use dbdeployer), here are some commands to make it right the first time

Requirements

You need to have MySQL 8.0 installed and running on both servers and with the same initial data (a fresh install for example). Here we use mysql1 and mysql2. We will also use GTID as it’s much more convenient.

Servers Configuration

Let’s setup mysql1 first:

mysql1> SET PERSIST server_id=1; 
mysql1> SET …

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There are various ways to shutdown MySQL. The traditional cross platform method is to use the shutdown command in the mysqladmin client. One drawback is that it requires shell access; another is that it cannot start MySQL again automatically. There are platform specific options that can perform a restart such as using systemctl on Linux or install MySQL as a service on Microsoft Windows. What I will look at here though is the built in support for stopping and restarting MySQL using SQL statements.

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Alpha Build of Percona Server 8.0 released

An alpha version of Percona Server 8.0 is now available in the Percona experimental software repositories. This is a 64-bit release only. 

You may experiment with this alpha release by running it in a Docker container:

$ docker run -d -e MYSQL_ROOT_PASSWORD=password -p 3306:3306 perconalab/percona-server:8.0.12.alpha

When the container starts, connect to it as follows:

$ docker exec -ti $(docker ps | grep -F percona-server:8.0.12.alpha | awk '{print $1}') mysql -uroot -ppassword

Note that this release is not ready for use in any production environment.

Percona Server 8.0 alpha is available for the following …

Alexey made this amazing tool that the majority of MySQL DBAs are using, but if you use sysbench provided with your GNU/Linux distribution or its repository on packagecloud.io you won’t be able to use it with the new default authentication plugin in MySQL 8.0 (caching_sha2_password).

This is because most of the sysbench binaries are compiled with the MySQL 5.7 client library or MariaDB ones. There is an issue on github where Alexey explains this.

So if you want to use sysbench with MySQL 8.0 …

Experimental Build of Percona XtraBackup 8.0 released

An experimental alpha version of Percona XtraBackup 8.0.1 is now available in the Percona experimental software repositories.

A few things to note about this release:

• We removed the deprecated innobackupex in this release
• Due to the new MySQL redo log and data dictionary formats the Percona XtraBackup 8.0.x versions will only be compatible with MySQL 8.0.x and the upcoming Percona Server for MySQL 8.0.x
• For experimental migrations from earlier database server versions, you will need to …

In my previous blog post about millions of table in MySQL 8, I was able to create one million tables and test the performance of it. My next challenge is to create 40 million tables in MySQL 8 using shared tablespaces (one tablespace per schema). In this blog post I’m showing how to do it and what challenges we can expect.

Background

Once again – why do we need so many tables in MySQL, what is the use case? The main reason is: customer isolation. With the new focus on security and privacy (take GDPR for example) it is much easier and more beneficial to create a separate schema (or “database” in MySQL terms) for each customer. That creates a new set of challenges that we will need to solve. Here is the summary:

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Join Percona Chief Evangelist Colin Charles as he covers happenings, gives pointers and provides musings on the open source database community.

There has been a lot of talk around licenses in open source software, and it has hit the database world in the past weeks. Redis Labs relicensed some AGPL software to the Commons Clause (in their case, Apache + Commons Clause; so you can’t really call it Apache any longer). I’ll have more to say on this topic soon, but in the meantime you might enjoy reading Open-source licensing war: Commons Clause. This was the most balanced article I read about this move and the kerfuffle it has caused. We also saw this with Lerna (not database related), and here’s another good read: …

In April, I already posted an article on how to upgrade safely your MySQL InnoDB Cluster, let’s review this procedure now that MySQL 8.0.12 is out.

To upgrade all the members of a MySQL InnoDB Cluster (Group), you need to keep in mind the following points:

• upgrade all the nodes one by one
• always end by the Primary Master in case of Single Primary Mode
• after upgrading the binaries don’t forget to start MySQL without starting Group Replication (group_replication_start_on_boot=0)
• to run mysql_upgrade

Let’s see this in action on the video below:

As you could see, this is quick and easy.

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