cedric's blog

This one is for all MySQL-DBA's, which are working on macOS. Since the Apple OS has a rather peculiar way of starting and stopping MySQL, compared to Linux, you can run into some issues. These problems occur especially, if you have no access to the GUI.

What is SELinux?

The Security-Enhanced Linux is an extension to the Linux Kernel, made by the NSA (National Security Agency). It implements Mandatory Access Controls (MAC), which allow an administrator to define, how applications and users can access resources on a system.

Somebody recently asked, what they had to do, if they wanted to move their InnoDB-Logfiles back to the datadir. As a challenge, the servers were part of a Galera Cluster.

My first thought was:

The problem is not the Galera Cluster itself, it is the rsync-SST (wsrep_sst_method = rsync) that could cause trouble and destroy your InnoDB-Logfiles, by simply overwriting or deleting them.

Recently I was working on a clients question and stumbled over an issue with replication and mixed character sets. The client asked, wether it is possible to replicate data to a table on a MySQL slave, where one column had a different character set, than the column in the same table on the master.

I recently managed to get my certification as MySQL 5.6 DBA, and was asked to write a blog about it, because I had trouble getting the informations I needed.

You may have figured out too, that Oracle does not really supply you with information about the certification. At least, there is the MySQL documentation. It contains all the information you need.

One of our customers recently ran into a problem, where he wanted to have a preferred donor for SST, whenever a node came up. The problem was, that the node did not come up, when the preferred donor was not running.

Most of you know, that it is possible to synchronize MySQL and MariaDB servers using replication. But with the latest releases, it is also possible to use more than just two servers as a multi-master setup.

Most of you know that both MySQL and MariaDB support replication in a hierarchical master-slave-setup, to propagate changes across all connected servers.

But with the latest releases, a slave can have more than one master.

The keyword: Multi-Source replication

It is supported from MySQL 5.7 and MariaDB 10.0 on, and this article describes how to set it up.

In my first Blog ever, I am going to cover the migration of a SQLite-Database to MySQL. The Tool used is MySQL-Workbench, which you can Download from the MySQL website. In this particular case, it is about the upgrade of mocenter 0.2 to 0.3.