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MySQL Data Types Explained

This tutorial explains all MySQL data types, their characteristics, and min, max as well as possible default values. We’ll describe their usages so that you can use them efficiently for creating schemas and tables. A MySQL table can have one or more fields with specific data types such as a string or date. However, there are more available in MySQL to ease up your job of collecting and storing data. It is also crucial that you understand which data type should you use and when. Here are some standard goals that define them what do they represent: 1. The data,

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MySQL TIMESTAMP with Simple Examples

This tutorial explains MySQL TIMESTAMP and TIMESTAMP field characteristics such as automated initialization and updating. We’ll describe their usages with the help of simple examples. 1. TIMESTAMP Syntax 2. TIMESTAMP Simple Examples 3. Set Timezone and Use Timestamp 4. Auto Init and Update Timestamp Let’s now go through each of the section one by one. MySQL TIMESTAMP The MySQL TIMESTAMP is a transient data type that contains a mixture of date and time. It is exactly 19 characters long. The structure of a TIMESTAMP field is as follows: Syntax # MySQL Timestamp YYYY-MM-DD HH:MM:SS The TIMESTAMP value shows in UTC

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Database Systems and Indexes – What you should know about Indexes for Performance Optimization ?

Optimal Indexing for Performance – How to plan Index Ops. ? 

An index or database index is a data structure which is used to quickly locate and access the data in a database table. Indexes are created on columns which will be the Search key that contains a copy of the primary key or candidate key of the table. These values are stored in sorted order so that the corresponding data can be accessed quickly (Note that the data may or may not be stored in sorted order). They are also Data Reference Pointers holding the address of the disk block where that particular key value can be found. Indexing in database systems is similar to what we see in books. There are complex design trade-offs involving lookup performance, index size, and index-update performance. Many index designs exhibit logarithmic (O(log(N))) lookup performance and in some applications it is possible to achieve flat (O(1)) performance. Indices can …

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MySQL InnoDB Cluster, automatic provisioning, firewall and SELinux

You may have noticed that in many of my demos, I disable firewall and SELinux (I even use --initialize-insecure sometimes ). This is just to make things easier… But in fact enabling iptables and SELinux are not complicated.

Firewall

These examples are compatible with Oracle Linux, RedHat and CentOS. If you use another distro, the principle is the same.

For the firewall, we need first to allow incoming traffic to MySQL and MySQL X ports: 3306 and 33060:

# firewall-cmd --zone=public --add-port=3306/tcp --permanent
# firewall-cmd --zone=public --add-port=33060/tcp --permanent

If you don’t plan to restart the firewall, you just need to run the same commands without --permanent to make then immediately active.

Then we need to allow the Group Replication’s communication port. This is usually 33061 but it can be configured in …

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MySQL Server 8.0.17: Thanks for the Contributions

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MySQL 8.0.17 was released Monday and it includes great features such as the Clone feature and multi-valued indexes. There are also several nice contributions from the community. These are the changes that this blog is about.

The contributions to MySQL Server 8.0.17 include patches from Facebook, Daniël van Eeden, Mattias Jonsson, and Simon Mudd (all from Booking.com), Daniel Black, Yibo Cai (from Arm Technology), Josh Braden, and Zhou Mengkang. The larger contributions are:

  • The mysql client program now sends os_user and os_sudouser connection attributes, when available, to indicate the name of the operating system user running the program and the value of the SUDO_USER environment variable, respectively. For general information …
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Improved handling of different member versions in Group Replication

For optimal compatibility and performance, all members of a group should run the same version of MySQL Server and therefore of Group Replication. However, in some situations, it may be required to that a group contains servers running different versions. For example, during a rolling upgrade.…

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MySQL Router 8.0.17’s REST API & MySQL Shell Extensions

You have seen in this previous post, that since 8.0.17, it’s now possible to query the MySQL Router using its REST API.

Additionally, we also saw in this post, that since 8.0.17, we are now able to write extensions to MySQL Shell using the Extension Framework.

Let’s combine both and see how we can integrate the MySQL Router’s REST API in the Shell.

I’ve created an extension in ext.router that creates a MySQL Router Object.

The new extension, as a method to create the object:

This is an example that illustrates how to create a MySQL Router Object, as you can see you can pass the password directly as parameter but it’s not recommended in interactive mode. It’s …

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How to move the Relay role to another node in a Composite Tungsten Cluster

The Question Recently, a customer asked us:

How would we manually move the relay role from a failing node to a slave in a Composite Tungsten Cluster passive site?

The Answer The Long and the Short of It

There are two ways to handle this procedure manually when the usual switch command fails to work as expected. One is short and reasonably automated, and the other is much more detailed and manual.

Of course, the usual procedure is to just issue the switch command in the passive cluster:

use west
set policy maintenance
switch
set policy automatic

The below article describes what to do when the switch command does not move the relay role to another node.

SHORT

Below is the list of cctrl commands that would be run for the basic, short version, which (aside from handling policy changes) is really only three …

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MySQL 8.0.17 and Drupal 8.7

From Drupal’s website, we can see that now the support of MySQL 8 is ready.

I just tested it and it works great !

The only restriction is related to PHP and the support for the new authentication method in php-mysqlnd.

In this previous post, I was happy because it was included in PHP 7.2.8, but this has been reverted back since then. Currently none of the latest version of PHP 7.x is supporting this authentication method.

We can easily verify this, first with the PHP version provided by default in Oracle Linux 8:

# php -i | grep "Loaded plugins\|PHP Version " | tail -n2
PHP Version => 7.2.11
Loaded plugins => mysqlnd,debug_trace,auth_plugin_mysql_native_password, …
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How to Run PHP 5 Applications with MySQL 8.0 on CentOS 7

Despite the fact that PHP 5 has reached end-of-life, there are still legacy applications built on top of it that need to run in production or test environments. If you are installing PHP packages via operating system repository, there is still a chance you will end up with PHP 5 packages, e.g. CentOS 7 operating system. Having said that, there is always a way to make your legacy applications run with the newer database versions, and thus take advantage of new features.

In this blog post, we’ll walk you through how we can run PHP 5 applications with the latest version of MySQL 8.0 on CentOS 7 operating system. This blog is based on actual experience with an internal project that required PHP 5 application to be running alongside our new MySQL 8.0 in a new environment. Note that it would work best to run the latest version of PHP 7 alongside MySQL 8.0 to take …

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