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Preventing Stale Reads on Percona XtraDB Cluster by Enforcing Causality Checks on a Per-Query Basis

When we run a SELECT in a replica server and it returns a different result to the one we would have obtained had we queried the source server instead, due to changes in the dataset that have not yet been replicated or synchronized to the replica, we get what is known as a stale read. My colleague Marcelo has blogged about Stale Reads and How to Fix Them before.

The need to avoid stale reads is a constraint that leads people into migrating to Percona XtraDB Cluster (PXC) / Galera Cluster or, more recently, Group Replication. I am focusing on PXC and Galera in this short blog post, which, similar to Group Replication, implements not exactly a synchronous replication model but what is commonly referred to as a …

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How to Resolve “Error Reading Relay Log Event” After Relay Log Corruption

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 …
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From email to myTinyTodo

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 …

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Percona XtraBackup 8.0.29 and INSTANT ADD/DROP Columns

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 …

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OpenLampTech issue #35 – Substack Repost

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
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Iris Data Set with MySQL HeatWave Machine Learning & Zeppelin

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.

MySQL Router Restful API

MySQL Router with InnoDB Cluster allows transparent routing access for application to backend MySQL Servers.  

Restful API (Http access) feature was added to MySQL Router since 8.0.17.

This article is written to provide a tutorial with Router Restful API.   It is tested with MySQL 8.0.29 release.


Setup& Assumptions

1. MySQL InnoDB Cluster 8.0.29 - Cluster Name as 'mycluster'

2. Linux OS with MySQL Shell 8.0.29 installed

3. Restful API User : 'myapiuser'


Router Configuration

Bootstrap is the process to create the Router configuration setup.   

e.g.

$> mysqlrouter --bootstrap admin:adminPassword@node1:node1Port --directory /tmp/myrouter --account routerfriend …

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Exploring MySQL on Kubernetes with Minkube

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 …

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MySQL HeatWave Database Service is available in 32 regions, including Mexico

MySQL HeatWave Database Service is now available in Querétaro, Mexico.

New MySQL HeatWave capabilities released in first half of 2022

New MySQL HeatWave capabilities released in first half of 2022

Showing entries 1496 to 1505 of 44029
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