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 …

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 …

Overview The Skinny

In this blog post we will discuss how the managed cross-site replication streams work in a Composite Multi-Master Tungsten Cluster for MySQL, MariaDB and Percona Server.

Agenda What’s Here?

• Briefly explore how managed cross-site replication works in a Tungsten Composite Multi-Master Cluster
• Describe the reasons why the default design was chosen
• Explain the pros and cons of changing the configuration
• Examine how to change the configuration of the managed cross-site replicators

Cross-Site Replication A Very Brief Summary

In a standard Composite Multi-Master (CMM) deployment, the managed cross-site replicators pull Transaction History Logs (THL) from every remote cluster’s current master node. …

Feeling the FOMO? Now you don’t have to! With the Percona Live Open Source Database Conference 2019 Live Stream, you’ll practically be there in person, living the experience to the fullest. Our keynote stage features morning and lunchtime keynotes on Wednesday, May 29th and morning keynotes on Thursday, May 30th. Join us at home or on the go, from any corner of the world!

Percona is streaming the keynotes on Wednesday, May 29, 2019, at 9 AM CDT, Wednesday, May 29, 2019, at 1:25 PM CDT, and Thursday, May 30, 2019, at 9 AM, beginning at 9 AM CDT.

Keynote speakers include Continuent, VividCortex, AWS, Facebook, MariaDB Foundation, and many more. The keynote panel will feature topics such as the changing face of Open Source.

The list of keynote talks and speakers for each day is as follows:

…

In this blog, we will see how to do a flashback recovery or rolling back the data in MariaDB, MySQL and Percona.

As we know the saying  “All humans make mistakes”, following that in Database environment the data modified accidentally can bring havoc to any organisations.

Recover the lost data

• The data can be recovered from the latest full backup or incremental backup when data size is huge it could take hours to restore it.
• From backup of Binlogs.
• Data can also be recovered from delayed slaves, this case would be helpful when the mistake is found immediately, within the period of delay.

We can use anyone of the above ways or other that can help to recover the lost data, but what really matters is, What is the …

The Question Recently, a customer asked us:

Why would Tungsten Replicator be slow to apply to MySQL?

The Answer Performance Tuning 101

When you run trepctl status and see:
appliedLatency : 7332.394
like this on a slave, it is almost always due to the inability for the target database to keep up with the applier.

This means that we often need to look first to the database layer for the solution.

Here are some of the things to think about when dealing with this issue:

Architecture and Environment
√ Are you on bare metal?
√ Using the cloud?
√ Dev or Prod?
√ Network speed and latency?
√ Distance the data needs to travel?
√ Network round trip times? Is the …

errno: 24 - Too many open files
You might see this error inside MySQL's error log file or during mysql_upgrade operation.

Can't open file: ‘./db/table.frm' (errno: 24 - Too many open files)
To solve this issue, you will need to change the open files limit at system and db service level.

--> To check and change this limit at the system level, we use ulimit client tool to set it dynamically.

* Check current system open file limit.
root@test:~# ulimit -a core file size          (blocks, -c) 0 data seg …