After I updated a Fedora 30 instance, I could no longer connect to the MySQL database. An attempt to connect raised the following error:

Error: Can't connect to local MySQL server through socket '/var/lib/mysql/mysql.sock' (2)

My guess was correct, the mysqld.service got removed during the update (a synonym for upgrade). So, I ran the following command as a sudoer user:

sudo systemctl enable mysqld.service

It creates the following symbolic link:

Created symlink /etc/systemd/system/multi-user.target.wants/mysqld.service → /usr/lib/systemd/system/mysqld.service.

That would start the MySQL Daemon (mysqld) on the next restart of the OS. However, I didn’t want to restart to have access to the service. I simply started it with the following command:

sudo systemctl start mysqld.service

Then, I could connect to the MySQL database. As always, …

MySQL Backup and Disaster Recovery Webinar (Thursday, June 18, 2020 – 06:00 PM to 07:00 PM PDT)

There can be several reasons for a MySQL database outage: hardware failure, power outage, human error, natural disaster etc. We may not be able prevent all the disaster from happening but investing on a robust disaster recovery plan is very important for building fault-tolerant database infrastructure operations on MySQL.  Every MySQL DBA is accountable for developing a disaster recovery plan addressing data sensitivity, data loss tolerance and data security. Join Shiv Iyer, Founder and Principal of MinervaDB to lean about the best practices for building highly reliable MySQL DR strategy and operations on Thursday, June 18, 2020 – 06:00 PM to 07:00 PM PDT. Building DR for a high traffic MySQL database infrastructure means deep understanding of multiple backup strategies and choosing optimal ones which are best suited for performance …

Just recently, I have been asked to look into what a Disaster Recovery site for InnoDB Cluster would look like.

If you’re reading this, then I assume you’re familiar with what MySQL InnoDB Cluster is, and how it is configured, components, etc.

Reminder: InnoDB Cluster (Group Replication, Shell & Router) in version 8.0 has had serious improvements from 5.7. Please try it out.

So, given that, and given that we want to consider how best to fulfill the need, i.e. create a DR site for our InnoDB Cluster, let’s get started.

Basically I’ll be looking at the following scenario:

InnoDB Cluster Source site with a Group Replication Disaster Recovery Site.

Now, just before we get into the nitty-gritty, here’s the scope.

Life is already hard enough, so we want as much automated as possible, so, yes, InnoDB Cluster gets some of that done, but there are other parts we will still have …

Codership is proud to announce the first Generally Available (GA) release of Galera Cluster 4 for MySQL 8 and improve MySQL High Availability a great deal. The current release comes with MySQL 8.0.19 and includes the Galera Replication Library 4.5 with wsrep API version 26. You can download it now (and note that we have packages for various Linux distributions). 

Galera 4 and MySQL 8.0.19 have many new features, but here are some of the highlights:

• Streaming replication to support large transactions by splitting transaction replication then applying them in smaller fragments. You can use this feature to load data faster, as data is written to all nodes simultaneously (or not at all in case of a failure in any single node).
• Improved …

On Monday April 27th, MySQL released a much-anticipated patch release 8.0.20. Along with many bug fixes and improvements, a new property was introduced – binlog-transaction-compression. During our own internal testing we have discovered an incompatibility with our Continuent Tungsten products when this property is enabled.

The newly-released binlog-transaction-compression feature is really interesting because it compresses transaction payloads before being written into the binary logs, which in turn reduces the disk space overhead required for storage. I’m sure many users will be keen to implement this, however at this time the use of binlog-transaction-compression=ON will prevent Replication from functioning correctly.

This …

Since the beta of Galera Cluster 4 with MySQL 8 has been released, we’ve had people asking questions as to how to install it on Ubuntu 18.04. This blog post will cover just that.

Prerequisites

• All 3 nodes need to have Ubuntu 18.04 installed
• Firewall (if setup) needs to accept connections on 3306, 4444, 4567, 4568 (a default setup has the firewall disabled)
• AppArmor disabled (this is as simple as executing: systemctl stop apparmor and systemctl disable apparmor).

Installation and Configuration

We have good installation documentation as well as a quick how to get this installed in AWS (though this is CentOS centric).

First, you will need to ensure that the …

My students want to transfer their course setup MySQL files from the Linux VM that I provide to Microsoft Windows 10. This post explains how because I found a couple small errors in the Google’d posts they would most likely see.

The first step is required because when I didn’t assign a name or domain to the the Fedora VM, which allows it to run as localhost on any student machine. In tandem, I didn’t assign a static IP address but opted for dynamic IP assignment. That means, the first step to securely copy the files requires you to find the assigned IP address. You can do that with the following Linux command:

ifconfig -a | grep 'inet[[:blank:]]' | head -1 | cut -c 14-30

It would return something like:

192.168.147.198

After you have discovered the IP address, you need to download PuTTy from their web site because includes the pscp (PuTTy …

MySQL NDB Cluster 8.0.20 new features 

This post is about changes in the implementation of NDB Cluster from MySQL NDB Cluster 8.0 through 8.0.20, as compared to earlier release series. We have included only those of MySQL NDB Cluster 8.0.20 new features which are really interesting and can directly influence / make an impact to performance, scalability and reliability:

• MySQL NDB Cluster  development is in parallel with the development of  MySQL Server going forward. What does that mean for MySQL customers globally NDB 8.0 is developed in, built from, and released with the MySQL 8.0 source code tree and numbering scheme for NDB Cluster 8.0 releases follows the scheme for MySQL 8.0 ( starting with version 8.0.13).
• As of NDB 8.0.18, The identifiers can use up to 64 bytes for databases and tables (the 63-byte limit on identifiers is removed ).
• Generated names for foreign keys …

A time for new beginnings beckons upon us, and Codership is pleased to announce the much anticipated Release Candidate of MySQL 8.0 that comes with Galera 4. It comes with MySQL 8.0.19 and includes the Galera Replication Library 4.5 Release Candidate and wsrep API version 26. 

Galera 4 and MySQL 8.0.19 have many new features, but here are some of the highlights:

• Streaming replication to support large transactions by splitting transaction replication then applying them in smaller fragments.
• Improved foreign key support, as write set certification rules are optimised and there will be a reduction in the number of foreign key related false conflicts in certifications.
• Group commit is …

It’s the in-between term time and we’re all stuck at home. I decided to update the image for my Fedora 30 virtual machine. I had a work around to the update issue that I had encountered last October in Bug #96969 but it was not required with the current version. However, after updating from MySQL 8.0.17 to MySQL 8.0.19, I found that my Java connection example failed.

The $CLASSPATH value was correct:

/usr/share/java/mysql-connector-java.jar:.

The first error that I got was the my reference to MySQL JDBC driver was incorrect. The error message is quite clear:

Loading class `com.mysql.jdbc.Driver'. This is deprecated. The new driver class is `com.mysql.cj.jdbc.Driver'. The driver is automatically registered via the SPI and manual loading of the driver class is generally unnecessary.
Cannot connect to database server:
The server time zone …