In this two-part blog series, I wanted to cover some failover scenarios with Group Replication. In part one, I will discuss an interesting behavior and performance degradation I discovered while writing these posts. In part two, I will show several failover scenarios and demonstrate how Group Replication handles each situation.

The test environment is very basic, a three-node Group Replication (mysql1,mysql2,myslq3) on MySQL 8.0.19 with default settings. mysql2 is the Primary node.

In this scenario, I was testing a partial network failure when a node gets separated from the primary, but other nodes still can see it.

You would think mysql3 is going to lose quorum and exit the cluster, but no. Inside the cluster, all the nodes are in constant communication with each other, not just …

Percona XtraDB Cluster 8.0 is in the final stretch before GA release and we have pre-release packages available for testing, and I wanted to see how Percona XtraDB Cluster 8.0 performs in CPU and IO-bound scenarios, like in my previous posts about MySQL Group Replication.

In this blog, I want to evaluate Percona XtraDB Cluster 8.0 scaling capabilities in I/O bound cases when we increase the number of nodes and increase user connections. The version I used is available here: …

Databases are complicated software made to handle the concurrent load while making specific guarantees about data consistency and availability. There are many scenarios which should be tested that can only happen under concurrent conditions.

Pstress is a probability-based open-source database testing tool designed to run in concurrency and to test if the database can recover when something goes wrong. It generates random transactions based on options provided by the user. With the right set of options, users can test features, regression, and crash recovery. It can create the concurrent load on a cluster or on a single server.

The tool is currently in beta, but it has already become very important within the testing pipeline for Percona. Pstress is widely used by Percona’s QA team during each phase of testing. It has …

Percona XtraDB Cluster 8.0 is on the final stretch before GA release, and we have pre-release packages available for testing.

I wanted to see how Percona XtraDB Cluster 8.0 performs in CPU and IO-bound scenarios, like in my previous posts about MySQL Group Replication.

In this blog, I want to evaluate Percona XtraDB Cluster 8.0 scaling capabilities in cases when we increase the number of nodes and increase user connections. The version I used is available here: Percona-XtraDB-Cluster-8.0.18. …

When connecting to a local MySQL instance, you have two commonly used methods: use TCP/IP protocol to connect to local address –  “localhost” or 127.0.0.1  – or use Unix Domain Socket.

If you have a choice (if your application supports both methods), use Unix Domain Socket as this is both more secure and more efficient.

How much more efficient, though?  I have not looked at this topic in years, so let’s see how a modern MySQL version does on relatively modern hardware and modern Linux.

Benchmarking  TCP/IP Connection vs Unix Domain Socket for MySQL

I’m testing Percona Server for MySQL 8.0.19 running on Ubuntu 18.04 on a Dual Socket 28 Core/56 Threads Server.  (Though I have validated results on 4 …

The backup and restore of a complete database is an extensive exercise. But what if you need to restore just one table which has been mistakenly modified by an incorrect query? Help is at hand with Percona XtraBackup.

For our purpose, we will take a test database having tables created by the sysbench tool. The 8.0 versions of Percona XtraBackup and Percona Server for MySQL have been used in this test.

Restore Single Table

Here we will take the backup of the sbtest2 table and restore it. The initial checksum of the table is given below:

8.0.19>CHECKSUM TABLE sbtest2;
+--------------+-----------+
| Table        | Checksum | …

Percona Server for MySQL 8.0.19 includes the experimental simple LDAP authentication plugin, which allows for direct authentication using an LDAP server. Similarly to the data masking plugin added in 8.0.18, this plugin was also added as a community contribution from Francisco Miguel Biete.

Authenticating with LDAP

In earlier versions, Percona Server for MySQL supported the built-in authentication mechanism of MySQL and also included a port of the PAM plugin from MySQL enterprise.

As LDAP servers can be configured as backends for PAM, this already provided a way to authenticate SQL users using LDAP, by adding PAM as an intermediate layer — requiring setting up both the auth_pam plugin and configuring PAM to use LDAP for authenticating mysqld users.

With this …

We recently released an experimental version of percona-dbaas command-line tool with the goal of significantly simplifying the deployment of database instances in Kubernetes.

We have Kubernetes Operators for Percona XtraDB Cluster and Percona Server for MongoDB, which provide great flexibility, but they also come with the complexity of managing configuration and deployment files, so we wanted to make it even simpler to deploy database instances. We found it hard enough to get a MySQL instance up and running in Kubernetes, and then a whole different process to get MongoDB up, and we thought it should be a unified set of commands. This is how the percona-dbaas CLI tool was born. You can get more information on installation of the percona-dbaas-cli tool and in this …

While there is no magic bullet for MySQL 5.7 database tuning, there are a few areas that can be focused on upfront that can dramatically improve the performance of your MySQL installation. While much information has been published on this topic over the years, I wanted to break down some of the more critical settings that anyone can implement – with no guesswork required.

Depending on the version of MySQL you are running, some of the default values used in this post may differ from your install, but the premise is still largely the same. We will focus on MySQL 5.7 for the purposes of this article.

Initial MySQL performance tuning can be broken down to the following categories:

• Tuning for your hardware
• Tuning for best performance/best practices
• Tuning for your workload

MySQL 5.7 Database Tuning Tuning For Your Hardware

Depending on the hardware …

In my Webinar on Using Percona Monitoring and Management (PMM) for MySQL Troubleshooting, I showed how to use direct queries to ClickHouse for advanced query analysis tasks. In the followup Webinar Q&A, I promised to describe it in more detail and share some queries, so here it goes.

PMM uses ClickHouse to store query performance data which gives us great performance and a very high compression ratio. ClickHouse stores data in column-store format so it handles denormalized data very well. As a result, all query performance data is stored in one simple “metrics” table: