The latest from the MySQL community

Wooohooo MySQL 8.0.22 has been released today !

As usual, this release contains contributions from our great Community and let me thanks all the contributors on behalf of the MySQL Team.

MySQL 8.0.22 includes contributions from Denis Yarkovoy, Gord Thomson, Andrey Turbanov, Javier Matos Odut, Kan Liyong, Xiaoyu Wang, Daniël van Eeden, Krunal Bauskar, Eric Beuque and Facebook.

Thank you all for your great contributions. MySQL is an Open Source project, GPL, and we accept contributions !

Here is the list of the contributions above:

• Update command.cs by Denis Yarkovoy
• …

Dear MySQL users,

MySQL Shell 8.0.22 is a maintenance release of MySQL Shell 8.0 Series (a component of the MySQL Server). The MySQL Shell is provided under Oracle’s dual-license.

MySQL Shell 8.0 is highly recommended for use with MySQL Server 8.0 and 5.7. Please upgrade to MySQL Shell 8.0.22.

MySQL Shell is an interactive JavaScript, Python and SQL console interface, supporting development and administration for the MySQL Server. It provides APIs implemented in JavaScript and Python that enable you to work with MySQL InnoDB cluster and use MySQL as a document store.

The AdminAPI enables you to work with MySQL InnoDB cluster and InnoDB ReplicaSet, providing integrated solutions for high availability and scalability using InnoDB based MySQL databases, without requiring advanced MySQL expertise. For more information about how to configure and work with MySQL InnoDB cluster and MySQL InnoDB ReplicaSet see

For what reason should I use a real multi-primary setup?

To be clear, not a multi-writer solution where any node can become the active writer in case of needs, as for Percona XtraDB Cluster (PXC) or Percona Server for MySQL using Group_replication. No, we are talking about a multi-primary setup where I can write at the same time on multiple nodes. I want to insist on this “why?”.

After having excluded the possible solutions mentioned above, both covering the famous 99.995% availability, which is 26.30 minutes of downtime in a year, what is left?

Disaster Recovery? Well, that is something I would love to have, but to be a real DR solution we need to put several kilometers (miles for imperial) in the middle.

And we know …

This blog post is referring to the uploaded slides.

DBT2 is based on the standard benchmark TPC-C. This benchmark is a mix of read

and write activity. It is much more write intensive than many other benchmarks.

This has resulted that performance in NDB in previous versions have only scaled

to nodes with around 6 LDM threads. With the introduction of multiple sockets

for communication between nodes we have been able to remove this limitation.

Thus DBT2 serves as a good tool to verify that MySQL Cluster 8.0.20 has improved

its capability to scale writes.

To our disposal for those tests we had access to a set of bare metal servers in

the Oracle Cloud (OCI). The data nodes used DenseIO2 bare metal servers with

…

Schema changes are the big challenges in Galera replication. So, it is recommended to understand the schema changes operation for everyone who uses the Percona XtraDB Cluster (PXB)/Galera clusters. In this blog, I am going to explain the operation and impact of the various schema changes methods used in the PXB/Galera cluster.

• Schema changes with “wsrep_OSU_method = TOI”
• Schema changes with “wsrep_OSU_method = RSU”
• Schema changes with “ONLINE ALGORITHMS”
• Schema changes with “pt-osc”
• Schema changes with “gh-ost”

For testing:

• I have configured the 3-node Percona Xtradb Cluster (8.0.19).
• Executing read/write load using the sysbench.

mysql> select @@wsrep_cluster_address\G
*************************** 1. row …

MySQL 8.0 has been with us already for quite some time and many MySQL users have already upgraded to this version. For those who are still using older MySQL versions, we would like to present this blog where we will share some tips and information that help in the upgrade process for MySQL 8.0.

Mind Your Version

Software versions are quite important in the upgrade process. For starters, only one major version difference is supported. You have to be running MySQL 5.7 before you can upgrade to MySQL 8.0. This is quite important to keep …

Hello everyone, in this little post we will review a new feature in MySQL 8.

What is “CHECK Constraint”?

This is a new feature to specify a condition to check the value before INSERT or UPDATE into a row. The constraint could return an error if the result of a search condition is FALSE for any row of the table (but not if the result is UNKNOWN or TRUE).

This feature starts working on MySQL 8.0.16, and in previous versions, we could create it, but it doesn’t work, meaning the syntax is supported but it is not working,

There are some rules to keep in mind…

– AUTO_INCREMENT columns are not permitted
– Refer to another column in another table is not permitted
– Stored functions and user-defined functions are not permitted (you can not call a function or any user-defined functions)
– Stored procedure and function parameters are not permitted (you cannot call …

Maybe one of the more “obscure” operations when dealing with replica lag, or, in general, when one needs to control writes to the database, is the Rate limit. It’s also lately one of the most popular conversations around the community.

But what is it? In plain words: holding up queries for a while, giving air to the replicas to breath and catch up. Something similar to the Galera’s Flow Control mechanism, although flow control, when it kicks in, stops all the writes while the nodes catch up. With a throttle no write is stopped, just delayed.

There are several ways to do this. A popular tool is Freno but this is also something that can be achieved with ProxySQL. Let’s see how.

Delay

ProxySQL has a variable called …

MySQL semi-sync is a plugin mechanism on top of asynchronous replication, that can offer better durability and even consistency (term defined later). It helps in high availability solutions, but can in itself reduce availability. We look at some basics and follow up to present scenarios that require higher level intervention to ensure availability and to avoid split brains from taking place.

I recommend reading this semi-sync blog post by Jean-François Gagné (aka JFG), which illustrates the internals of the semi-sync implementation, and debunks some myths about semi-sync. We will overlap a bit with another recommended post by JFG, about high availability and recovery. …

Creating the database for an application is simple and easy. However, database script management gets complicated in a hurry when you need to support multiple versions, work with multiple teams, and apply the same changes to multiple types of databases. 

One open-source tool that helps teams track, version, and deploy database schema changes is Liquibase. It executes database scripts sequentially, allows for the automatic creation and execution of rollback scripts for failed updates, and provides an easy way to use the same scripts and apply them to different types of databases. To illustrate how Liquibase works, here’s an example using PostgreSQL.   

System set up:

• Download the latest version of Liquibase. 
• …