News

Table of contents

• Overview
• Preparations
• Activate MaxScale configuration synchronisation
• Change MaxScale parameters
• Add new slave and make MaxScale known
• Remove old slave and make MaxScale known
• How is the configuration synchronised?
• What happens in the event of a conflict?
• Tests
• Deactivating MaxScale configuration synchronisation again
• Literature/sources

Overview

A feature that I recently discovered while browsing is the MaxScale configuration synchronisation functionality.

This is not primarily about a …

Table of contents

• Overview
• Preparation of the shards (MariaDB database instances)
  • Create test data
  • Creating roles and users
  • MaxScale Monitor User
  • MaxScale Admin User
  • Create application role and accounts
  • Proxy protocol
• MaxScale SchemaRouter configuration
• Starting and stopping the MaxScale Load Balancer
• Application tests
  • Simple application tests
  • New command show shards
  • More general test
  • Less simple tests
  • More complex application tests
  • Cross-shard tests
• Operation of a MaxScale sharding system …

Table of contents

• Functionality of dbstat
• How does dbstat work
• How to install dbstat
• Query dbstat
  • table_size
  • processlist
  • trx_and_lck
  • metadata_lock
  • global_variables
  • global_status
• Testing
• Sources

An idea that I have been thinking about for a long time and have now, thanks to a customer, finally tackled is dbstat for MariaDB/MySQL. The idea is based on sar/sysstat by Sebastien Godard:

sar - Collect, report, or save system activity information.

and Oracle Statspack:

Statspack is a performance tuning …

FromDual has the pleasure to announce the release of the new version 2.1.0 of its popular MariaDB, Galera Cluster and MySQL multi-instance environment MyEnv.

The new MyEnv can be downloaded here. How to install MyEnv is described in the MyEnv Installation Guide.

In the inconceivable case that you find a bug in the MyEnv please report it to the FromDual bug tracker.

Any feedback, statements and testimonials are welcome as well! Please send them to …

• MyEnv 2.1.0 Release Notes: MariaDB/MySQL Environment MyEnv 2.1.0 has been released (2024-02-28)
• MyEnv 2.0.3 Release Notes: MariaDB/MySQL Environment MyEnv 2.0.3 has been released (2021-07-02)
• MyEnv 2.0.2 Release Notes: MariaDB/MySQL Environment MyEnv 2.0.2 has been released (2019-01-17)
• MyEnv 2.0.1 Release Notes: MariaDB/MySQL Environment MyEnv 2.0.1 has been released (2018-10-03)
• MyEnv 2.0.0 Release Notes: MySQL Environment MyEnv 2.0.0 has been released (2018-03-15)
• MyEnv 1.3.1 Release Notes: MySQL …

The design of a data warehouse differs from relational design. Data warehouses are often designed according to the concept of the star schema.

When building a data warehouse, you usually put the cart before the horse:

• What questions should my data warehouse be able to answer?
• How do I have to design my model so that my questions can be answered easily?
• Where do I get the data to populate the model?
• How do I fill my model with the data?

For training purposes, we have investigated an issue that arises from …

FromDual has the pleasure to announce the release of the new version 2.1.0 of its popular Database Performance Monitor for MariaDB and Galera Cluster fpmmm.

The FromDual Performance Monitor for MariaDB (fpmmm) enables DBAs and System Administrators to monitor and understand what is going on inside their MariaDB database instances and on the machines where the databases reside.

More detailed information you can find in the fpmmm Installation Guide.

Download

The new FromDual Performance Monitor for MariaDB ( …

Translated by deepl.com

Introduction

Two points in advance:

1. A deadlock is a state in which two different transactions are no longer able to continue working because each transaction holds a lock that the other transaction would need. Because both transactions are now waiting for the other transaction to release their locks, neither transaction will release their respective locks. And that would last forever. To avoid this, the MariaDB instance intervenes and kills the transaction that has done less work. …

Scenario: MariaDB Community Server is release every 3 months. The exact date is not known but it is typically about 2 to 3 weeks after the MySQL/Oracle CPU.

We upgrade regularly customer systems, also their MariaDB Galera Cluster systems. Because we made in the past some very bad experience upgrading production MariaDB Galera Clusters short after release date we became a bit more careful. Our new policy is: We wait a few weeks before installing a new release.

This week we had the situation that on Monday a …

FromDual has the pleasure to announce the release of the new version 1.2.1 of its 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 DBA’s and System Administrators to better manage their MariaDB and MySQL databases and Galera Cluster farms. Ops Center makes DBA and Admins life easier!

The main task of Ops Center is to support you in your daily MariaDB and MySQL operation tasks. …

FromDual has the pleasure to announce the release of the new version 1.2.0 of its 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 DBA’s and System Administrators to better manage their MariaDB and MySQL databases and Galera Cluster farms. Ops Center makes DBA and Admins life easier!

The main task of Ops Center is to support you in your daily MariaDB and MySQL operation tasks. …

Table of Contents

• SystemD Notizen
• InnoDB NUMA interleave with MariaDB
• Checking Galera Cluster SST timeout with SystemD
• Kill MariaDB Galera node under SystemD
• MariaDB Memory locking (--memlock) with SystemD
• Who is restarting my mariadbd?
• Location of SystemD unit files

SystemD Notizen

SystemD paged per default nach less. Das ist ungewohnt und doof, weil es gegen allgemeines Linux-Verhalten verstösst. Abhilfe schafft:

shell> systemctl --no-pager status
shell> alias systemctl='systemctl --no-pager'

Das …

A while ago I read a paper about Optimizer Benchmarks: How Good Are Query Optimizers, Really? by Viktor Leis from Fakultät für Informatik of the Technische Universität München.

Because we have from time to time problems with slow queries of customers especially after upgrading to new database releases it is interesting for me, how different optimizers cope with a query. Sometimes it is not clear to me why the query is slow or how I can make it faster. So the mentioned paper inspired me to compare the same …

Before you consider migrating your data from MySQL to another database you have to know which objects have to be migrated.

With this query you will find the objects to consider:

SELECT TABLE_SCHEMA AS `SCHEMA`, IF(TABLE_TYPE = 'BASE TABLE', 'TABLE', TABLE_TYPE) AS OBJECT_TYPE, TABLE_NAME AS `OBJECT_NAME`
     , IFNULL(ENGINE, '') AS ENGINE, IFNULL(TABLE_ROWS, '') AS `ROWS`
     , IFNULL(DATA_LENGTH, '') AS DATA_SIZE, IFNULL(INDEX_LENGTH, '') AS INDEX_SIZE
  FROM information_schema.tables
 WHERE TABLE_SCHEMA …

If you do not feel at home on the command line, you may prefer to use a graphical user interface (GUI). These also have advantages, for example when displaying data or structures, or they can simplify and therefore speed up work processes.

There are two main types of graphical user interfaces: On the one hand, the Integrated Development Environments (IDE), and on the other hand, tools that support the administration of the database.

This list contains all known graphical user interfaces for MariaDB and …

Sometimes SQL developers ask me if there is a difference between putting the Filter in the WHERE Clause and putting the Filter in the ON Clause and if yes, what the difference is. To explain it the best I have stolen a little example (Source at the end):

CREATE TABLE department (
  department_id   INT UNSIGNED NOT NULL
, department_name VARCHAR(14)
, location        VARCHAR(13)
, PRIMARY KEY (department_id)
);

INSERT INTO department (department_id, department_name, location)
VALUES
  (10, 'ACCOUNTING', …

Currently we are in the testing phase of the next release of our Ops Center (focmm). This testing is quite complex because it includes testing the interaction of various different components like a MariaDB Galera Cluster, a Galera Load Balancer, a virtual IP, etc.

Recently I was in the Linuxhotel for a Galera Cluster Training and there one of the other trainers was romanticising about Linux Containers and Incus. So I had a short look, if Incus could be useful to simplify our unit testing. Some old knowledge …

The newest release of the Performance Monitor for MariaDB and MySQL v2.0.0 (fpmmm) allows you to monitor your MariaDB and MySQL databases via SNMP (Simple Network Management Protocol).

This feature enables you to report your Database Metrics into Enterprise Monitoring solutions from Microsoft, IBM or into Oracle Cloud Control.

In this article we will show you the few simple steps it needs to send the data from your fpmmm Agent to your SNMP Manager.

Check if SNMP Manager can be reached

To make sure fpmmm can …

FromDual has the pleasure to announce the release of the new version 2.0.0 of its popular Database Performance Monitor for MariaDB and Galera Cluster fpmmm.

The FromDual Performance Monitor for MariaDB (fpmmm) enables DBAs and System Administrators to monitor and understand what is going on inside their MariaDB database instances and on the machines where the databases reside.

More detailed information you can find in the fpmmm Installation Guide.

Download

The new FromDual Performance Monitor for MariaDB ( …