The latest from the MySQL community

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, …

A few days ago, a customer got in touch asking how they could use Percona Monitoring and Management (PMM) to monitor the roles played by each node in an InnoDB cluster. More specifically, they wanted to check when one of the nodes changed its role from Primary to Secondary, or vice-versa. PMM allows for a high level of flexibility and customization through its support for custom queries, and we just have to be creative on how we approach the problem. In this post, we present the steps we did to test our solution, including the deployment of a 3-node InnoDB Cluster hosted in the same server (for testing) and a PMM 2 server, and connecting them together. Even though this has already been covered in other blog …

In this blog post, we are going to look into how to perform online migration from MySQL 5.6 standalone setup to a new replication set running on MySQL 5.7, deployed and managed by ClusterControl. 

The plan is to set up a replication link from the new cluster running on MySQL 5.7 to the master running on MySQL 5.6 (outside of ClusterControl provision), which uses no GTID. MySQL does not support mixing GTID and non-GTID in one replication chain. So we need to do some tricks to switch between non-GTID and GTID modes during the migration.

Our architecture and migration plan can be illustrated as …

How to Migrate Single MySQL Enterprise Server to Three Node MySQL Enterprise  InnoDB Cluster latest version 8.0.20 ?
Assume current you production work loads resembles multiple app server and all are point to single MySQL Server.  have you thought about below questions ?
1. what if , this database goes down ? this is single point of failure ? 2. what if, data loss ? 3. Scalability ? 4. Data Inconsistencies ? 5. DR?
BTW, i am using MySQL Enterprise Edition ,  more info:-  https://www.mysql.com/products/enterprise/
To address these basic questions on SLA , RPO/RTO ,  MySQL has another high availability solutions which is developed by MySQL Engg team, which has no noisy neighbors all components are tested by MySQL Engg team.
MySQL InnoDB Cluster= MySQL Server + MySQL Shell + MySQL …

In most cases, MySQL password instructions provide information on changing MySQL user passwords on the production system (e.g., reset root password without restart). It is even recommended to change passwords regularly for security reasons. But still, sometimes DBA duties on legacy systems offer surprises and you need to recover the original password for some old users.

There is no magic: as long as only hashes are stored and not the original passwords, the only way to recover the lost password is to brute force it from the known hash.

Note on Security and mysql-unsha1 Attack

Interestingly, if a hacker has access to password hash and can sniff mysql traffic, he doesn’t need to recover a plain text password from it. It doesn’t matter how strong the password and how strong the hashing …

Day-to-day database operation requires, from an administrator, deep knowledge of db internals and security issues, in particular things like SQL injections. In order to prevent such kind of an attack, we have included go-sql-driver into our code for secure placeholder escaping.

Unfortunately, not all cases are secured by the driver.

In case we are using the standard driver for working with MySQL, if we need to pass a variable to the database query, we use a placeholder “?” in order for the server to understand that it needs to process the incoming variable to avoid injection. It works fine with just regular SELECT/INSERT/UPDATE statements, but, unfortunately, MySQL server is not able to process all types of queries.

For example:

db.Exec("CREATE USER ?@? IDENTIFIED BY ?", name, host, pass)

This query will return an error from the …

Three weeks ago, I released the Pluto Beta of Planet for the MySQL Community.  Since then, a few things changed and I think it is worth doing an update to the Ecosystem.  The change I am the most happy about is that Ivan Groenewold started helping with the project (you can find him in the people of the oursqlcommunity.org GitHub organization).  So Planet for the MySQL Community is

A common MySQL strategy to perform updates with accumulating functions is to employ user-defined variables, using the UPDATE [...] SET mycol = (@myvar := EXPRESSION(@myvar, mycol)) pattern.

This pattern though doesn’t play well with the optimizer (leading to non-deterministic behavior), so it has been deprecated. This left a sort of void, since the (relatively) sophisticated logic is now harder to reproduce, at least with the same simplicity.

In this article, I’ll have a look at two ways to apply such logic: using, canonically, window functions, and, a bit more creatively, using recursive CTEs.

• Requirements and background
• …

First I want to thank everyone who attended my May 21, 2020 webinar “How Safe is Asynchronous Master-Master Setup in MySQL?“. Recording and slides are available on the webinar page.

Here are answers to the questions from participants which I was not able to provide during the webinar.

Q: What do you generally think of hosting Relational Databases on VM’s as opposed to Bare metals?

A: With modern hardware and modern virtual machines this is absolutely possible. I know about many successful high loaded applications that run MySQL on VMs.

Just note that running a few VMs on a single physical machine may lead to resource loss rather than saving. For …

With this post we are reaching the end of our journey to HA for WordPress & MySQL 8.0 on OCI.

If you have not read the two previous articles, this is just the right time.

• MySQL 8.0 InnoDB ReplicaSet with WordPress in OCI
• MySQL 8.0 InnoDB ReplicaSet with WordPress in OCI – part II

We started this trip using the MySQL InnoDB ReplicaSet where only 2 servers are sufficient but doesn’t provide automatic fail-over.

In this article we will upgrade our InnoDB ReplicaSet to …