Shinguz's blog

Last week at the MariaDB/MySQL Developer Training we had one participant asking some tricky questions I did not know the answer by heart.

InnoDB Page Cleaner Thread

The InnoDB Page Cleaner Thread is an InnoDB background thread that flushes dirty pages from the InnoDB Buffer Pool to disk. Prior MySQL 5.6 this action was performed by the InnoDB Master Thread.

Table of Contents

• General findings
• Migration from MySQL 5.x to MariaDB 5.5
• Migration from MySQL 5.0 to MariaDB 10.3
• Migration from MariaDB 10.0 to Percona Server 5.6
• Migration from MySQL/Percona 5.6 to MariaDB 10.0
• Migration from MySQL 5.7 to MariaDB 10.2
• Migration from MySQL 5.7 to MariaDB 10.3
• Migration from MySQL 5.7 to MariaDB 10.4
• Migration from Percona XtraDB Cluster 5.5 to MariaDB Galera Cluster 10.4
• Migration from MySQL 5.7 to MariaDB 10.5
• Migration from MySQL 5.7 to MariaDB 10.6
• Migration from MySQL 5.7 to MariaDB 10.6 on Windows

More and more MySQL users want to switch from MySQL/Percona Server to MariaDB over time or, more rarely, the other way around. This is mostly caused by the change of the default in the Linux Distributions (RHEL/CentOS 7, SLES 12, Debian 8) to MariaDB.
Up to MySQL/MariaDB 5.5 everything was quite easy, both Branches claim to be a drop-in replacement of each other. But after the separation into different forks (MariaDB 10.0 ff. vs. MySQL 5.6 ff.) we expect more and more problems migrating from one branch to the other what we call sidegrade.
Percona Server code is genetically closer to MySQL than MariaDB. So we expect to see less problems on this sidegrade.

A while ago somebody on Google Groups asked for the Uptime of a Galera Cluster. The answer is easy… Wait, no! Not so easy… The uptime of a Galera Node is easy (or not?). But Uptime of the whole Galera Cluster?

We had the problem today that a MySQL Galera Cluster node with the multi-tenancy pattern caused a lot of system time (sy 75%, load average about 30 (you really must read this article by Brendan Gregg, it is worth it!)) so we wanted to find what system calls are being used to see what could cause this issue (to verify if it is a TOC or a TDC problem:

We see at various customers the request for consolidating their MariaDB and MySQL infrastructure. The advantage of such a measure is clear in the first step: Saving costs! And this request comes typically from managers. But what we unfortunately see rarely is to question this request from the IT engineering perspective. Because it comes, as anything in life, with some “costs”. So, saving costs with consolidation on one side comes with “costs” for operation complexity on the other side.

FromDual has the pleasure to announce the release of the new version 1.0.2 of its popular Database Performance Monitor for MariaDB, MySQL, Galera Cluster and Percona Server fpmmm.

Since January 2019 FromDual tries to contribute actively a little bit against global warming too.

FromDual has the pleasure to announce the release of the new version 2.1.0 of its popular Backup and Recovery Manager for MariaDB and MySQL (brman).

MySQL Enterprise Backup (MEB) is a bit limited related to support of older MySQL versions. So you should consider the following release matrix:

The FromDual Enterprise Tools are licensed under a FromDual commercial license. The one exception is MyEnv which is licensed under GPLv2.

Early adopters of our customers are considering to upgrade to MySQL 8.0. To be prepared we have created a check-list:

FromDual has the pleasure to announce the release of the new version 2.0.2 of its popular MariaDB, Galera Cluster and MySQL multi-instance environment MyEnv.

See also Byobu.

See also our older article: Using screen for support and/or surveillance.

As we already stated in earlier articles in this blog
[1 and 2
] it is a good idea to use NULL values properly in MariaDB and MySQL.

Yes, I am aware that this is not a NULL issue. I hope my blog did not tell that this is be cause of NULL.

Hello,

Just wanted to say that the post misses the point. The problem is not NULL values as such. the problem is:

We see sometimes at customers that they have very big InnoDB system tablespace files (ibdata1) although they have set innodb_file_per_table = 1.

In the recent MariaDB DBA advanced training class the question came up if MariaDB can make use of an index when searching for NULL values… And to be honest I was not sure any more. So instead of reading boring documentation I did some little tests:

FromDual has the pleasure to announce the release of the new version 2.0.1 of its popular MariaDB, Galera Cluster and MySQL multi-instance environment MyEnv.