Although how range_optimizer_max_mem_size operates is explained in the official doc, it’s not a well-known variable and surely not a variable you need to modify under most circumstances. But from time to time we get some performance tickets related to this.

What problem does this variable cause if it is not properly sized? Let’s find out with an example!

Given the following table definition:

CREATE TABLE `joinit` (
  `i` int(11) NOT NULL AUTO_INCREMENT,
  `s` varchar(64) DEFAULT NULL,
  `t` time NOT NULL,
  `g` int(11) NOT NULL,
  PRIMARY KEY (`i`)
) ENGINE=InnoDB AUTO_INCREMENT=2490316 DEFAULT CHARSET=latin1

With ~2M rows

select count(*) from joinit ;
+----------+
| count(*) |
+----------+
|  2097152 |
+----------+

With the default value of  range_optimizer_max_mem_size = 8388608, the following …

… an expedition to uncover (and fix) database performance issues!

© 2021 Tiago L. Alves. All rights reserved.

One of the worse things that can happen when upgrading to a newer database version is discovering that the performance is not as good as before. Despite the effort put into gate-keeping MySQL NDB Cluster’s strict performance requirements, one of our customers found a performance regression when upgrading from our 7.4 version to our 7.6 version. How did that happen when our automated performance test suite failed to show it? To answer that, and fix the issue we enrolled on a database performance archaeology expedition…

When your performance is not good enough

MySQL NDB Cluster is an open-source in-memory distributed database developed for high-availability (99.999% or more) and predictable query times. It can be found at the core of gaming, banking, telecommunication, and online services. …

This article is the second part of the series related to MySQL Invisible Column started here.

This post covers why Invisible Column is important for InnoDB Storage Engine.

To start, let me explain briefly how InnoDB deals with Primary Key and why an good primary key is important. And finally, why having a Primary Key is also important.

How does InnoDB Stores Data?

InnoDB stores data in table spaces. The records are stored and sorted using the clustered index (the primary key): they are called index-organized tables.

All secondary indexes also contain the primary key as the right-most column in the index (even if this is not exposed). That means when a secondary …

The MySQL Development Team is happy to announce a new 8.0 Maintenance Release of MySQL Shell AdminAPI – 8.0.23!

In addition to several bug fixes and minor changes, some significant enhancements regarding monitoring/troubleshooting and performance were included.

MySQL Shell AdminAPI Cluster diagnostics

Checking how a Cluster is running and, whenever the cluster is not 100% healthy, perform troubleshooting tasks is certainly one of the main tasks of a DBA.…

Facebook Twitter LinkedIn

With the new MySQL 8.0.23, something very interesting has been released: Invisible Column.

This is the first post dedicated to this new feature, I expect to write a series of 3. This one is the introduction.

Prior to MySQL 8.0.23, all columns of a table were always visible (if you had the privilege to see it). Now, an invisible column can be specified and will be hidden to queries. It can always be accessed if explicitly referenced.

Let’s see how it works:

create table table1 (
   id int auto_increment primary key, 
   name varchar(20), 
   age int invisible);

In the table description we can see the INVISIBLE keyword in the Extra column:

desc table1; …

I recently published a blog post about a portfolio project I am developing using the LAMP stack, Bootstrap 4, jQuery, and the MVC (Model-View-Controller) design pattern in core PHP. In this post, I will introduce an additional feature I integrated into the existing project.

Image by xresch from Pixabay

Self-Promotion:

If you enjoy the content written here, by all means, share this blog and …

As a continue of the regular blog posts informing you about where you can find MySQL Community & MySQL team at, please find below a list of shows you can join and listen MySQL talks & sessions. 

• January 2021:

  • Coud Native Meetup/VIRTUAL, January 26, 2021 - URL to be provided later on.
    • Frederic Descamps, the MySQL User Group Manager will talk on: "MySQL 8.0: Why to use MySQL 8.0 and how to deploy a web application in OCI using MySQL Database Service" 
    • Scheduled for January 26th as EMEA & JAPAC session & January 27th, 2021.
  • OpenSource Conference Osaka/VIRTUAL, January 30, 2021
    • Yoshiaki Yamasaki, the MySQL …

Large replication topologies are quite common nowadays, and this kind of architecture often requires a quick method to rebuild a replica from another server.

The Clone Plugin, available since MySQL 8.0.17, is a great feature that allows cloning databases out of the box. It is easy to rebuild a replica or to add new nodes to a cluster using the plugin. Before the release of the plugin, the best open-source alternative was Percona XtraBackup for MySQL Databases.

In this blog post, we compare both alternatives for cloning purposes. If you need to perform backups, Percona XtraBackup is a better tool as it supports compression and incremental backups, among other features not provided by the plugin. The plugin supports compression only for network transmission, not for storage.

But one of the plugin’s strong points is simplicity. …

In this article, we are going to see how to set up a MySQL Database instance on Microsoft Azure Cloud.

The post MySQL in Azure first appeared on dasini.net - Diary of a MySQL experts.

The expected version 8.0.23 of MySQL has been released yesterday \o/

For new features and resolved bugs, I recommend Geir‘s traditional blog post announcing the release.

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

MySQL 8.0.23 includes contributions from Daniel Black, Vilnis Termanis, Venkatesh Prasad Venugopal, Daniël van Eeden, Cai Yibo, Kamil Holubick, Shaohua Wang, Krunal Bauskar, Tzachi Zidenberg, Cédric Luthi, Brian Yue, Hope Lee and Facebook.

Thank you all for your great contributions. MySQL is an Open Source project, GPL, …