The MySQL database is used in thousands of third-party applications, but what can you do when you want to use MySQL with an application, but that application’s queries or data doesn’t match MySQL’s data type or SQL format?

This post will show you three ways to alter a query or mismatched data when you don’t have control of the application’s source code. Of course, there are hundreds of different ways to do what I am about to show you. In this example, I will show you how to use the MySQL Query Rewrite Plugin along with a trigger to alter the non-conforming data. I will also show you an example of manipulating data with a stored procedure.

A customer emailed me with a problem. They wanted to use …

Introduction to resource groups in MySQL 8 and dynamical allocation to threads

The post MySQL 8 Resource Group – introduction and dynamic allocation first appeared on Change Is Inevitable.

I wrote MySQL and JSON: A Practical Programming Guide to help developers find their way around the MySQL JSON data type and the supporting functions. The MySQL Documentation on the subject is very good but I had to puzzle through the examples to see how things worked.  I might be a bit 'thick' but good examples always make things easier.  Others seem to have similar difficulties.

 There was a recent post on …

This is the same plugin that Alex Gorvachev created back in the day. I’ve simply modified it to be compatible with both 12c and 13c versions.

I created this in response to a comment on the blog about issues deploying the plugin in OEM 13c. There is also a note in MOS “EM 13c: Adding a MySQL Instance in Enterprise Manager 13c Fails with Error: oracle.sysman.emSDK.agent.client.exception.NoSuchMetricException: the Load metric does not exist (Doc ID 2160785.1)“.

This version has been tested with OEM 13cR2 and OEM 12cR3, so it should be working in all the versions in between except for bugs.

Caveats

During the …

Basics of MySQL Cluster

This PDF introduces the basic architecture of MySQL Cluster and how to
access it with various APIs.

Traditionally infrastructure management is a manual task, with sysadmins managing rather static servers. The automation capabilities of modern cloud platforms have changed this way of working: Infrastructure is often described “as code,” e.g. in a git repository, and changes are made by infrastructure management systems automatically. As a result infrastructure is much less static and turnaround […]

The following statement usually is valid and the function returns 1. But sometimes it is invalid and sometimes the function returns 0.

CREATE FUNCTION f() RETURNS INT DETERMINISTIC
BEGIN
  DECLARE a CHAR DEFAULT 'a';
  IF a = 0 || a > 0 THEN RETURN 1; END IF;
  RETURN 0;
END;

Why?

First, consider that "||" is usually the same as "OR" because that's the default. But if sql_mode is 'ansi' and the DBMS is MySQL 8.0, then "||" is the operator for concatenating strings. So the meaning of the IF condition changes, and it becomes false.

Second, consider that the function is written with SQL/PSM syntax. But if sql_mode is 'oracle' and the DBMS is MariaDB 10.3, then the function has to be written with PL/SQL syntax. And the requirements differ as soon as the word "RETURNS" comes along, so the result is a syntax error.

Our lesson is: you can't know a statement's meaning if you don't know whether somebody said …

Peter Zaitsev of Percona posted a Tweet about an interactive book Select Star SQL which 'aims to be the best place on the internet for learning SQL'.  This interactive book uses a data set that can be downloaded or you could work the queries online.  I showed the website to a neighbor who was asking 'what is the best way to learn SQL'.   The neighbor wanted their own copy of the data and asked how do you turn a raw CSV file into a table.

Well, that can get complicated.
CSV
CSV files use commas to designate each field in the file.  This is a great idea until someone plants a comma in the middle of a field but it is sort of a least common denominator way of passing data between systems.

But a CSV file does not directly fit into a relational table.  You could …

Percona Monitoring and Management (PMM) is a free and open-source platform for managing and monitoring MySQL® and MongoDB® performance. You can run PMM in your own environment for maximum security and reliability. It provides thorough time-based analysis for MySQL® and MongoDB® servers to ensure that your data works as efficiently as possible.



We’ve included a plethora of visual improvements in this release, including:

• PostgreSQL Metrics Collection – Visualize PostgreSQL performance!
• Identify New Queries in Query Analytics
• New Dashboard: Compare System Parameters
• New Dashboard: PERFORMANCE_SCHEMA Wait Events Analysis
• Dashboard Updates – Advanced Data Exploration, MyRocks, TokuDB, InnoDB Metrics …

Codership is pleased to announce the release of Galera Replication library 3.24, implementing wsrep API version 25.  The new release includes improved deadlock error management with foreign keys and security fixes. As always, Galera Cluster is now available as targeted packages and package repositories for a number of Linux distributions, including Ubuntu, Red Hat, Debian, CentOS, OpenSUSE and SLES, as well as FreeBSD. Obtaining packages using a package repository removes the need to download individual files and facilitates the easy deployment and upgrade of Galera Cluster nodes.

This release incorporates all changes up to MySQL 5.7.23, MySQL 5.6.41 and MySQL 5.5.61.

Galera Replication Library 3.24
New features and notable fixes in Galera replication since last binary release by Codership (3.23)

* A support for new …