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In MariaDB master/slave replication there is a feature called attribute promotion/demotion.

Simply put, it is about how the slave behaves or should behave if the master and slave have different column definitions or even a different number of columns or a different sequence of columns.

Use case of the customer

This week we discussed with a customer the case of how he could perform a rolling schema upgrade (RSU) in a Galera cluster.

With previous schema changes he has always had problems, which has led to a total failure of the cluster for several hours.

The customer says that columns are never deleted and new columns are only ever added at the end of a table.

And that it is NOT possible to ensure that there are no more write connections during the rolling schema upgrade.

The PHP ORM framework Doctrine is used.

What does the MariaDB documentation say about this?

The study of the MariaDB documentation did not lead to a conclusive result whether a rolling schema upgrade in the running Galera Cluster operation …

FromDual has the pleasure to announce the release of the new version 2.3.2 of its popular Backup and Recovery Manager for MariaDB and MySQL (brman).

The new FromDual Backup and Recovery Manager can be downloaded from here. The FromDual Repositories were updated. How to install and use the Backup and Recovery Manager is described in FromDual Backup and Recovery Manager (brman) installation guide.

In the inconceivable case that you find a bug in the FromDual Backup and Recovery Manager please send us an [email](mailto:contact@fromdual.com?Subject=Bug report for brman).

Any feedback, statements and testimonials are welcome as well! Please send them to feedback@fromdual.com.

Upgrade from 2.x to 2.3.2

$ cd /opt
$ tar xf /download/brman-2.3.2.tar.gz
$ rm -f brman
$ ln -s brman-2.3.2 brman

Changes in FromDual Backup and Recovery Manager 2.3.2

This release is a new minor release. It contains mainly bug fixes. We have tried to maintain backward-compatibility with the 1.2, 2.0, 2.1, 2.2 and 2.3 release series. But you …

In our MariaDB advanced training courses, which we hold approximately every two months, we use machines that are directly exposed to the Internet with a public IP address. Warning: You should NEVER expose a database directly to the Internet without protection! Typically, it takes less than 72 hours (3 days) before we are exposed to the first external access attempts.

This looks something like this in the MariaDB error log:

[Warning] Aborted connection 22939 to db: 'unconnected' user: 'unauthenticated' host: '118.193.58.125' (This connection closed normally without authentication)
[Warning] Aborted connection 22940 to db: 'unconnected' user: 'unauthenticated' host: '118.193.58.125' (This connection closed normally without authentication)
[Warning] Access denied for user ''@'118.193.58.125' (using password: NO)
[Warning] Access denied for user 'root'@'118.193.58.125' (using password: YES)
[Warning] Access denied for user 'root'@'118.193.58.125' (using password: YES)

First of all, it was checked whether a …

Since 10.11 it would be good to use –dump-history if MariaDB System-Versioned Tables are used!

Recently I had the opportunity to have a lot of Linux systems (VMs with Rocky Linux 9) from one of our regular Galera Cluster trainings all to myself for a week. And MariaDB 11.4.4 with Galera Cluster was already installed on the machines.

Since I had long wanted to try out how a Galera Cluster behaves with an increasing number of nodes, now was the opportunity to try it out.

The following questions were to be answered:

• How does the throughput of a Galera cluster behave depending on the number of Galera nodes?
• Which configuration gives us the highest throughput?

A total of 5 different test parameters were experimented with:

• Number of Galera nodes.
• Number of client machines (= instances).
• Number of threads per client (--threads=).
• Number of Galera threads (wsrep_slave_threads).
• Runtime of the tests. This parameter was varied because some tests were cancelled during the run. It may be possible to eliminate this parameter with a lower rate (--rate) in the load test. As it turned out, it did have an influence …

We have improved our model (see v2) so the results are a bit better/more accurate now.

For usage see ./fromdual_llm_v2.php --help

Artificial intelligence (AI) and vector databases are on everyone’s lips these days. Since MariaDB will soon be coming onto the market with vector database functionality, as a database consultant I thought it was about time I got to grips with the subject so that I have at least a hint of what it’s all about…

Since I’m not so much of a theoretician but rather like to do something practical, I’ve built a small “AI” prototype that anyone can build very quickly and easily on their laptop (without a GPU)…

I also took the liberty of stealing the graphs from the MariaDB Foundation presentation (see sources at the end).

Downloading the MariaDB database with vector functionality

There are no MariaDB packages with vector functionality yet, but the source code is already available. So you can quickly build the binaries yourself. This took just under an hour on my old box. Once the binaries are built, you can make a tarball out of them:

# tar xf …

FromDual has the pleasure to announce the release of the new version 2.3.1 of its popular Backup and Recovery Manager for MariaDB and MySQL (brman).

The new FromDual Backup and Recovery Manager can be downloaded from here. The FromDual Repositories were updated. How to install and use the Backup and Recovery Manager is described in FromDual Backup and Recovery Manager (brman) installation guide.

In the inconceivable case that you find a bug in the FromDual Backup and Recovery Manager please report it to the FromDual Bugtracker or just send us an [email](mailto:contact@fromdual.com?Subject=Bug report for brman).

Any feedback, statements and testimonials are welcome as well! Please send them to feedback@fromdual.com.

Upgrade from 2.x to 2.3.1

shell> cd ${HOME}/product
shell> tar xf /download/brman-2.3.1.tar.gz
shell> rm -f brman
shell> ln -s brman-2.3.1 brman

Changes in FromDual Backup and Recovery Manager 2.3.1

This release is a new minor release. It contains mainly bug fixes. We have tried to …

What is it about?

When describing backup and restore scenarios, a full backup and a full restore of the database instance (mariadbd/mysqld) are usually assumed. This means that the entire database instance, including all databases (schemas), is backed up and restored.

In practice, however, the situation is often different: An entire database instance is not to be restored, but only individual databases or even individual tables, because only these have broken.

In many cases, this can be done quite easily with the tools mariadb-dump/mariadb or mysqldump/mysql (logical backup). However, if the database or table is very large, the restore will not be completed in a reasonable time (some minutes to a few hours).

This is exactly where the so-called partial physical restore comes into play. Partial stands for one or more tables (or an entire database), physical for: Individual SQL statements are not executed, but the data files are physically restored. In this scenario, very large amounts of data can be restored …

FromDual has the pleasure to announce the release of the new version 2.3.0 of its popular Backup and Recovery Manager for MariaDB and MySQL (brman).

The new FromDual Backup and Recovery Manager can be downloaded from here. The FromDual Repositories were updated. How to install and use the Backup and Recovery Manager is described in FromDual Backup and Recovery Manager (brman) installation guide.

In the inconceivable case that you find a bug in the FromDual Backup and Recovery Manager please report it to the FromDual Bugtracker or just send us an [email](mailto:contact@fromdual.com?Subject=Bug report for brman).

Any feedback, statements and testimonials are welcome as well! Please send them to feedback@fromdual.com.

Upgrade from 2.x to 2.3.0

shell> cd ${HOME}/product
shell> tar xf /download/brman-2.3.0.tar.gz
shell> rm -f brman
shell> ln -s brman-2.3.0 brman

Changes in FromDual Backup and Recovery Manager 2.3.0

This release is a new major release. The most important new feature is the partial …

One feature that really excited me in the new MariaDB 11.4 LTS release is the shrinking of the system tablespace (ibdata1). I have been eagerly waiting for this feature since around 2006 and now it has finally arrived with MariaDB 11.4. Actually, this feature has been available since MariaDB 11.2 IR (June 2023).

Unfortunately, the announcement of this feature came a little too short. In the MariaDB release notes it says succinctly:

The reasons why this file can grow immeasurably have actually been known for a long time and the measures against it are also clear (see literature). But again and again we see MariaDB users out in the field who didn’t realise the problem or realised it too late and are now left with an ibdata1 file that is far too large…

How can the problem be provoked?

The problem can be provoked by creating a table in the system tablespace:

SQL> …

https://jira.mariadb.org/browse/MDEV-34412

Hi dcz01

No it is not solved… It is closed and “not a bug”… I try to intervene

Regards, Oli

Hi Oli, Thanks for your answer. The problem is already open and solved but not for me and its still not working: https://jira.mariadb.org/browse/MDEV-28172

Greetings dcz01

Hello dcz01

I would say, this is probably a bug. I can reproduce it on my system (MySQL 5.7 Master and MariaDB 10.6 Galera Cluster).

Please contact your MariaDB support contact… If you need assistance we are happy to sell you our remote-DBA services…

Regards, Oli

Hi, we are migrating some old mysql 5.7 servers to new mariadb 10.5 machines with new galera 4 and we’re doing the normal way of migration:

• Dumping all databases from old servers and importing to new galera cluster (no error)
• Configuration of traditional sql replication between old and new servers so that clients still can connect to servers without downtime (no errors)
• Starting replication and just creating a new database (error and galera nodes which are not the replication slave are dropping with inconsistency from cluster)

Do you know what could be the failure here? You described it here very good but its not working so easy.

Greetings dcz01

On this page we have summarised information about downgrading a MariaDB/MySQL database. We do not cover migrating from MySQL to MariaDB or vice versa. For migrations (sidegrade) please look here: MySQL - MariaDB migration and here: Migration between MySQL/Percona Server and MariaDB.

The downgrade process tends to be neglected because nobody really wants to do it. So we are in swampy territory here. Unforeseen situations can occur very easily and good preparation is essential.

I can think of the following possible options for the downgrade:

• Restore the backup that was made BEFORE the upgrade began.
• Binary inplace downgrade (which is NOT supported in many cases).
• Dump (mariadb-dump/mysqldump) of the upgraded database and restore (mariadb/mysql) to the old version (logical backup/restore).
• Master/slave replication (with Statement Based Replication (SBR) or Row Based Replication (RBR)) and fallback to the slave with the old version.
• Partial Backup/Restore with mariadb-backup/xtrabackup (Transportable Tablespace …

FromDual is pleased to announce the release of the new version 1.2.2 of the popular FromDual Ops Center focmm, a Graphical User Interface (GUI) for MariaDB, MySQL and compatible databases.

The FromDual Ops Center for MariaDB and MySQL (focmm) helps DBAs and system administrators to better manage their MariaDB and MySQL databases and Galera Cluster farms. Ops Center makes life easier for DBAs and Admins!

The main purpose of the Ops Center is to help you with your daily MariaDB and MySQL operations. More information about FromDual Ops Center can be found in the General Information section.

Download now

The new FromDual Ops Center for MariaDB and MySQL (focmm) can be downloaded from our download page. How to install and use focmm is documented in the Ops Center User Guide.

In the unlikely event that you find a bug in the FromDual Ops Center for MariaDB and MySQL please report it to the FromDual bug tracker or just send us an [email](mailto:contact@fromdual.com?Subject=Bug report for focmm).

Any feedback, …

• Ops Center 1.2.2 Release Notes: FromDual Ops Center 1.2.2 for MariaDB, MySQL and compatible databases has been released (2024-04-25)
• Ops Center 1.2.1 Release Notes: FromDual Ops Center 1.2.1 for MariaDB, MySQL and compatible databases has been released (2023-02-07)
• Ops Center 1.2.0 Release Notes: FromDual Ops Center 1.2.0 for MariaDB, MySQL and compatible databases has been released (2023-01-17)
• Ops Center 1.1.0 Release Notes: FromDual Ops Center for MariaDB, MySQL and compatible databases 1.1.0 has been released (2021-05-07)
• Ops Center 1.0.0 Release Notes: FromDual Ops Center for MySQL and compatible databases 1.0.0 has been released (2020-05-07)
• Ops Center 0.9.3 Release Notes: FromDual Ops Center for MariaDB and MySQL 0.9.3 has been released (2020-02-18)
• Ops Center 0.9.2 Release Notes: FromDual Ops Center for MariaDB and MySQL 0.9.2 has been released (2019-08-13)
• Ops Center 0.9.1 Release Notes: FromDual Ops Center for MariaDB and MySQL 0.9.1 has been released (2019-05-07)
• Ops Center 0.9.0 Release Notes: …

Table of contents

• Review
• One month later
• Size of the tables
• Process list
• Global variables
• Metadata Lock and InnoDB Transaction Lock
• Global status

Review

After we introduced dbstat for MariaDB (and MySQL) a good 5 weeks ago, we naturally also rolled it out on our systems to test the behaviour in daily use (eat your own dog food).

This went quite well until we came up with the idea of activating dbstat on the passive dbstat node on our MariaDB active/passive master/master replication cluster (a similar situation would also occur with a Galera cluster). We realised that the design of dbstat still had potential. After this problem was fixed (v0.0.2 and v0.0.3) and the problem of how to activate events on master AND slave was solved (MDEV-33782: Event is always disabled on slave), everything seemed fine at first glance. Unfortunately, we did not realise that the data also had to be adjusted. As a result, our replication came to a complete stop over the Easter holidays, which then led to another problem when …