In this blog, I explain how to recover from a replication failure caused by a corrupted relay log file.

MySQL replica stores data received from its source binary log in the relay log file. This file could be corrupted due to various reasons, mostly hardware failures. If this happens, replication will stop working, and the error log on the replica will have entries similar to:

2022-05-12T12:32:07.282374Z 2 [ERROR] Error in Log_event::read_log_event(): 'Event too small', data_len: 0, event_type: 0
2022-05-12T12:32:07.282386Z 2 [ERROR] Error reading relay log event for channel '': slave SQL thread aborted because of I/O
...
2022-05-12T12:32:07.282396Z 2 [ERROR] Slave SQL for channel '': Relay log read failure: Could not parse relay log event entry. The possible reasons are: the master's binary log is corrupted (you can check this by running 'mysqlbinlog' on the binary log), the slave's relay log is corrupted (you can check this by running …

Usually, I receive a lot of emails, and sometimes I read them on my phone and then… I forgot about them.. (shame on me).

On my Linux desktop, I used to use Get Things Gnome for a long time, due to the declining appeal of the project and the end of the extension for Thunderbird, I found it less and less useful.

I was then looking for a solution to have my todolist accessible from everywhere and that I could manage it myself, not hosted somewhere.

I found a very nice, fast and practical project that was easy to deploy and was using MySQL as backend: myTinyTodo.

However, I was missing the possibility to easily create a new task from an email (and especially on my phone).

This is why I decided to write a script that would perform exactly what I was looking for and integrated …

Oracle’s MySQL 8.0.29 release extended the support for ALTER TABLE … ALGORITHM=INSTANT to 1) allow users to instantly add columns in any position of the table, and 2) instantly drop columns. As part of this work, the InnoDB redo log format has changed for all DML operations on the server. This new redo log format introduced a design flaw that can cause data corruption for tables with INSTANT ADD/DROP COLUMNS.

The corruption happens when InnoDB crash recovery takes place. InnoDB applies redo logs at startup. Percona XtraBackup copies the redo log during backup and applies it as part of the –prepare step to bring the backup to a consistent state.

Percona fixed the corruption issue and several other issues with the INSTANT ADD/DROP column …

Do you know what time it is? It’s time for your weekly media resource on all things MySQL, PHP, and LAMP stack! Like I always say, I hope you enjoy this issue of OpenLampTech as much as I did! Thank you for reading and please share the OpenLampTech publication with others!

The Newsletter for PHP and MySQL Developers

Receive a copy of my ebook, “10 MySQL Tips For Everyone”, absolutely free when you subscribe to the OpenLampTech newsletter.

This week in OpenLampTech issue #35, we are looking at articles covering:

• MySQL Joins
• PHP logical operators
• Linux sudo vs su
• A nice Laravel dev environment
…

During the last 20 years MySQL has democratized the usage of transactional databases.
Now with MySQL HeatWave we are in the process of democratizing Analytics and Machine Learning.

With MySQL HeatWave,
valorizing your data has never been so easy!

In this article I will show you how easy it is to use the Machine Learning capabilities of MySQL HeatWave. We will use the famous Iris dataset and we’re going to build, train, deploy and explain a machine learning model within MySQL HeatWave using Apache Zeppelin.

The post Iris Data Set with MySQL HeatWave Machine Learning & Zeppelin first appeared on dasini.net - Diary of a MySQL expert.

In this blog post, I will show how to install the MySQL-compatible Percona XtraDB Cluster (PXC) Operator on Minikube as well as perform some basic actions.   I am by no means a Kubernetes expert and this blog post is the result of my explorations preparing for a local MySQL Meetup, so if you have some comments or suggestions on how to do things better, please comment away!

For my experiments, I used Minikube version 1.26 with the docker driver in the most basic installation on Ubuntu 22.04 LTS, though it should work with other combinations, too. You also can find the official “Running Percona XtraDB Cluster on Minikube” documentation …

In this blog, I will demonstrate how to use Percona Monitoring and Management (PMM) to find out the reason why the MySQL server is stalling. I will use only one typical situation for the MySQL server stall in this example, but the same dashboards, graphs, and principles will help you in all other cases.

Nobody wants it but database servers may stop handling connections at some point. As a result, the application will slow down and then will stop responding.

It is always better to know about the stall from a monitoring instrument rather than from your own customers.

PMM is a great help in this case. If you look at its graphs and notice that many of them started showing unusual behavior, you need to react. In the case of stalls, you will see that either some activity went to 0 or, otherwise, it increased to high …

As a principal architect at Percona, one of my duties is to tune MySQL database servers for our customers. The tuning effort looks at every aspect of the database service like the operating system, the MySQL configuration, the schema, the queries, etc. We have well-defined processes to tune the operating system and the MySQL configuration. However, tuning the schema and the queries using it can be anywhere from trivial to extremely challenging.

The challenge with the schema and the queries is mostly with the indexes. The most common types of indexes are based on b-trees or hash lists. InnoDB doesn’t support hash indexes, a bummer for equality conditions. B-tree indexes are more general-purpose, they are decent for equality conditions and very good for range conditions. They are however quite heavy and very dependent on the defined order of columns. They are also poor for double range conditions.

Double range conditions can be …

Built on time-tested open-source software, the LAMP stack is a popular choice in modern Web Development. Continue reading this OpenLampTech publication report…

The Newsletter for PHP and MySQL Developers

Receive a copy of my ebook, “10 MySQL Tips For Everyone”, absolutely free when you subscribe to the OpenLampTech newsletter.

What is the LAMP stack?

The LAMP stack is a well-established combination of 4 pieces of software that form one of the most robust web application architecture stacks.

LAMP is actually an acronym created from the 1st letter of the name of each of the 4 components it is built from:

1. Linux – The operating system. …

If you write C applications that need to connect to MySQL, you can use the MySQL C API aka libmysqlclient. The MySQL C API replaces the outdated MySQL-Connector-C.

If you want to use MySQL 8.0 as a Document Store with the X Protocol, you need then to use MySQL Connector/C++ 8.0.

Some have asked how to compile only the MySQL C API.

Compiling only libmysqlclient

As the FAQ stipulates it, it’s not possible to only build the library. However, as mentioned in the documentation, it’s possible to reduce the amount of compiled products with some …