The latest from the MySQL community

In the first part of this blog, we covered a deployment walkthrough of MySQL InnoDB Cluster with an example on how the applications can connect to the cluster via a dedicated read/write port.

In this operation walkthrough, we are going to show examples on how to monitor, manage and scale the InnoDB Cluster as part of the ongoing cluster maintenance operations. We’ll use the same cluster what we deployed in the first part of the blog. The following diagram shows our architecture:

We have a three-node …

In this post, we will explore one approach to MySQL high availability with ProxySQL, Consul and Orchestrator.

This is a follow up to my previous post about a similar architecture but using HAProxy instead. I’ve re-used some of the content from that post so that you don’t have to go read through that one, and have everything you need in here.

Let’s briefly go over each piece of the puzzle:

– ProxySQL is in charge of connecting the application to the appropriate backend (reader or writer).

It can be installed on each application server directly or we can have an intermediate connection layer with one or more ProxySQL servers. The former probably makes sense if you have a small number of application servers; as the number grows, the latter option becomes more attractive. Another scenario for the …

To illustrate how easy it’s to see who’s trying to access data they have not been granted for, we will first create a schema with two tables:

mysql> create database mydata;
mysql> use mydata
mysql> create table table1 (id int auto_increment primary key, 
              name varchar(20), something varchar(20));
mysql> create table table2 (id int auto_increment primary key, 
              name varchar(20), something varchar(20));

Now, let’s create a user :

mysql> create user myuser identified by 'mypassword';

And as it’s always good to talk about SQL ROLES, let’s define 3 roles for our user:

• myrole1: user has access to both tables in their entirety, reads and writes
• myrole2: user has access only to `table2`, reads and writes
• myrole3: user has only access to the column `name`of `table1` and …

MySQL InnoDB Cluster consists of 3 components:

• MySQL Group Replication (a group of database server which replicates to each other with fault tolerance).
• MySQL Router (query router to the healthy database nodes)
• MySQL Shell (helper, client, configuration tool)

In the first part of this walkthrough, we are going to deploy a MySQL InnoDB Cluster. There are a number of hands-on tutorial available online but this walkthrough covers all the necessary steps/commands to install and run the cluster in one place. We will be covering monitoring, management and scaling operations as well as some gotchas when dealing with MySQL InnoDB Cluster in the second part of this blog post.

The following diagram illustrates our post-deployment architecture:

We are going to deploy a total of 4 nodes; A three-node MySQL Group Replication and one MySQL router node co-located within the application …

MySQL Cluster is an open-source distributed in-memory database. It combines linear scalability with high availability, providing in-memory real-time access with transactional consistency across partitioned and distributed datasets. It was developed to support scenarios requiring high-availability (99.999% or more) and predictable query time. Testing such a system is achieved via many interconnected pieces ranging from a large set of automated tests and manual exploratory testing. This post explores an overview of the testing methodologies we use and the current challenges we face.

Gaming, banking, telcos, and online services all are powered by fully-redundant and fault-tolerant software systems. At the heart of those systems, you can find MySQL Cluster — a distributed in-memory database having a minimum of five-9s availability (around 5 minutes a year). This open-source database provides nearly-linear …

From time to time you may have experienced that MySQL was not able to find the best execution plan for a query. You felt the query should have been faster. You felt that something didn’t work, but you didn’t realize exactly what.

Maybe some of you did tests and discovered there was a better execution plan that MySQL wasn’t able to find (forcing the order of the tables with STRAIGHT_JOIN for example).

In this article, we’ll see a new interesting feature available on MySQL 8.0 as well as Percona Server for MySQL 8.0: the histogram-based statistics.

Today, we’ll see what a histogram is, how you can create and manage it, and how MySQL’s optimizer can use it.

Just for completeness, histogram statistics have been available on MariaDB since version 10.0.2, with a slightly different …

Introduction In this article, we are going to see how a deadlock can occur in a relational database system, and how Oracle, SQL Server, PostgreSQL, or MySQL recover from a deadlock situation. Database locking Relational database systems use various locks to guarantee transaction ACID properties. For instance, no matter what relational database system you are using, locks will always be acquired when modifying (e.g., UPDATE or DELETE) a certain table record. Without locking a row that was modified by a currently running transaction, Atomicity would be compromised. Using locking for controlling access... Read More

The post A beginner’s guide to database deadlock appeared first on Vlad Mihalcea.

This article is an update of a previous post explaining how to setup a second cluster on a second data center to be used as disaster recovery (or to run some off site queries, like long reports, etc..).

This new article covers also the CLONE plugin. Before you ask, CLONE plugin and Replication Channel Based Filters are only available in MySQL 8.0 ! It’s time to upgrade, MySQL 8 is Great !

Also, for DR only, a single MySQL instance acting as asynchronous replica is enough. But if for any reason you want to also have a HA cluster in the second data …

MySQL introduced a JSON data type in version 5.7, and expanded the functionality in version 8.0.

Besides being able to store native JSON in MySQL, you can also use MySQL as a document store (doc store) to store JSON documents. And, you can use NoSQL CRUD (create, read, update and …

ProxySQL 2.0.7, released by ProxySQL, is now available for download in the Percona Repository along with Percona’s proxysql-admin tool.

ProxySQL is a high-performance proxy, currently for MySQL and database servers in the MySQL ecosystem (like Percona Server for MySQL and MariaDB). It acts as an intermediary for client requests seeking resources from the database. René Cannaò created ProxySQL for DBAs as a means of solving complex replication topology issues.

This release includes ProxySQL 2.0.7 which introduces many new features and enhancements and also …