The latest from the MySQL community

Trefft Carsten und Henry vom MySQL Team Deutschland auf der DOAG Datenbank 2019 (#DOAGDB19) am 3. und 4. Juni in Düsseldorf.

Wir sind mit einem kleinen Stand vertreten und Carsten wird am Montag von 14:15 bis 15:00 einen Vortrag zum Thema „MySQL, ein Einstieg in die 'andere' Datenbank von Oracle“ im Raum Amsterdam 2 halten. Das gesamte Programm für Montag und Dienstag lässt sich hier einsehen.

Wenn es im Vorfeld Fragen von Eurer Seite aus gibt, wendet Euch gerne per E-Mail an Henry [henry.kroger(at)oracle(dot)com].

Wir freuen uns …

We at Aiven are big believers in Open Source. Not only do we provide Open Source databases as a service, we are contributors to several of those and many related projects. Additionally, we open source our in-house tools we’ve developed to provide Aiven services whenever we can.

Getting the details just right to fully automate MySQL backups isn't simple. Find out how we accomplished it with our Open Source tool, MyHoard.

Getting the details just right to fully automate MySQL backups isn't simple. Find out how we accomplished it with our Open Source tool, MyHoard.

How to Prepare for MySQL Certification Exam

Here I am going to suggest MySQL DBA, student or any newbie that how they can prepare for "Oracle's MySQL 5.x Database Administrator" certification exam. 
Step 1: Lab
-- Prepare your local MySQL lab environment and make sure to install the respective MySQL version on your lab. (i.e., if you are going to appear on MySQL 5.6 DBA exam 1Z0-883 then install MySQL 5.6 on your lab) 
-- You can follow my below blog post to create your local MySQL lab …

Install MySQL on CentOS using DBdeployer
1. Here It is assumed You will have a CentOS system/VM. If not, then please find my this blog post link where you will get instruction about, how you can create CentOS virtual machine using the vagrant. 
2. Connect to CentOS VM abhinavs-MacBook-Air:centos7-test-vm agupta$ pwd /Users/agupta/vagrant_box/centos7-test-vm
abhinavs-MacBook-Air:centos7-test-vm agupta$ vagrant ssh 
[vagrant@centos7-test-vm ~]$ sudo su -
[root@centos7-test-vm ~]#
3. Run below command to install the latest …

The Question Recently, a customer asked us:

What is the meaning of this error message found in trepsvc.log?

2019/05/14 01:48:04.973 | mysql02.prod.example.com | [east - binlog-to-q-0] INFO pipeline.SingleThreadStageTask Performing rollback of possible partial transaction: seqno=(unavailable)

Simple Overview The Skinny

This message is an indication that we are dropping any uncommitted or incomplete data read from the MySQL binary logs due to a pending error.

The Answer Safety First

This error is often seen before another error and is an indication that we are rolling back anything uncommitted, for safety. On a master this is normally very little and would likely be internal transactions in the trep_commit_seqno table, for example.

As you may know with the replicator we always extract complete transactions, and so this particular message is …

This is a CRITICAL update and the fix mitigates the issues described in CVE-2019-12301. If you upgraded packages on Debian/Ubuntu to 5.6.44-85.0-1, please upgrade to 5.6.44-85.0-2 or later and reset all MySQL root passwords.

Issue

On 2019-05-18 Percona discovered an issue with the Debian/Ubuntu 5.6.44-85.0-1 packages for Percona Server for MySQL. When the previous versions, upgraded to the new version PS 5.6.44-85.0-1 on deb based systems, the MySQL root password was removed allowing users to login to the upgraded server as MySQL root without specifying a password.

Scope

This issue is limited to users who upgraded with the Debian/Ubuntu package 5.6.44-85.0-1 for Percona Server for MySQL v. 5.6. Newer versions (v. 5.7 and above) and new …

Database migrations don’t scale well. Typically you need to perform a great deal of tests before you can pull the trigger and switch from old to new. Migrations are usually done manually, as most of the process does not lend itself to automation. But that doesn’t mean there is no room for automation in the migration process. Imagine setting up a number of nodes with new software, provisioning them with data and configuring replication between old and new environments by hand. This takes days. Automation can be very useful when setting up a new environment and provisioning it with data. In this blog post, we will take a look at a very simple migration - from standalone Percona Server 5.7 to a 3-node Percona XtraDB Cluster 5.7. We will use Ansible to accomplish that.

Environment Description

First of all, one important disclaimer - what we are going to show here is only a draft of what you might like to run in production. It does …

I recently stumbled upon a very interesting post by Lukas Eder, where he describes 10 query transformations which do not depend on the database’s cost model. He posted it a couple of years ago, though when I read it, I assumed some portions of it may still be relevant today.

In the original post, several databases were tested to see if their internal optimizer will be able to automatically re-write the SQL queries and optimize them. In those tests, MySQL under-performed in several of the use cases (the tested version was MySQL 8.0.2, which was released on 2017-07-17).

Seeing those results, and given the previous evaluation was done almost two years ago, I thought that now can be a good chance to re-evaluate a few of those tests with the latest MySQL 8.0.16 (released on 2019-04-25), and demonstrate …