Shinguz's blog

Do not underestimate performance impacts of swapping on NUMA database systems

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If your MariaDB or MySQL database system is swapping it can have a significant impact on your database query performance! Further it can also slow down your database shutdown and thus influence the whole reboot of your machine. This is especially painful if you have only short maintenance windows or if you do not want to spend the whole night with operation tasks.




PERFORMANCE_SCHEMA in newer MariaDB releases

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PERFORMANCE_SCHEMA is invented/developed by Oracle/MySQL. So for MariaDB it is a foreign component and not supported too well...




Dropped Tables with FromDual Backup Manager

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Some applications have the bad behaviour to CREATE or DROP tables while our FromDual Backup Manager (bman) backup is running.




FromDual Ops Center for MariaDB and MySQL 0.9.1 has been released

FromDual has the pleasure to announce the release of the new version 0.9.1 of its popular FromDual Ops Center for MariaDB and MySQL focmm.




FromDual Ops Center for MariaDB and MySQL 0.9 has been released

Caution: We have introduced an evil bug which prohibits installation of focmm. Sorry! Somehow it did pass our QA. To fix this bug update file lib/Upgrade.inc on Line 1965 as follows:




MariaDB Prepared Statements, Transactions and Multi-Row Inserts

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




Understanding InnoDB - Buffer Pool Flushing

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.




MySQL - MariaDB migration

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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.




Uptime of a MariaDB Galera Cluster

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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?




Linux system calls of MySQL process

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:




MariaDB and MySQL Database Consolidation

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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.




MariaDB and MySQL consulting by plane

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







MySQL Enterprise Backup Support Matrix

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




FromDual Enterprise Tools License

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




Upgrade MySQL 5.7 to MySQL 8.0

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







To NULL, or not to NULL, that is the question!

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.




Re: MariaDB indexing of NULL values

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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.




MariaDB indexing of NULL values

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Hello,

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




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