I was recently asked a question by mail about MySQL Lossless Semi-Synchronous Replication. As I think the answer could benefit many people, I am answering it in a blog post. The answer brings us to the internals of transaction committing, of semi-synchronous replication, of MySQL (server) crash recovery, and of storage engine (InnoDB) crash recovery. I am also debunking some misconceptions that I have often seen and heard repeated by many. Let’s start by stating one of those misconceptions.

One of those misconceptions is the following (this is NOT true): semi-synchronous enabled slaves are always the most up-to-date slaves (again, this is NOT true). If you hear it yourself, then please call people out on it to avoid this spreading more. Even if some slaves have semi-synchronous replication disabled (I will use semi-sync for …

In this post we will see a case study of a Galera Cluster migration to AWS Aurora and quick solution to the replication issue. A friend received an error in…

The post Galera cluster to AWS Aurora migration & HA_ERR_FOUND_DUPP_KEY first appeared on Change Is Inevitable.

Recently, I wrote a blog post showing how to enforce SELinux with Percona XtraDB Cluster (PXC). The Linux distributions derived from RedHat use SELinux. There is another major mandatory discretionary access control (DAC) system, AppArmor. Ubuntu, for example, installs AppArmor by default. If you are concerned by computer security and use PXC on Ubuntu, you should enforce AppArmor. This post will guide you through the steps of creating a profile for PXC and enabling it. If you don’t want to waste time, you can just grab my profile, it seems to work fine. Adapt it to your environment if …

Please join Percona’s Architect, Tibi Köröcz as he presents Utilizing ProxySQL for Connection Pooling in PHP on Tuesday August 14, 2018, at 8:00 am PDT (UTC-7) / 11:00 am EDT (UTC-4).

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ProxySQL is a very powerful tool, with extended capabilities. This presentation will demonstrate how to use ProxySQL to gain functionality (seamless database backend switch) and correct problems (applications missing connection pooling).

The presentation will be a real-life study on how we use ProxySQL for connection pooling, database failover and load balancing the communication between our (third party) PHP-application and our master-master MySQL-cluster.
Also, we will …

In this post we will review the most important Linux settings to adjust for performance tuning and optimization of a MySQL database server. We’ll note how some of the Linux parameter settings used OS tuning may vary according to different system types: physical, virtual or cloud. Other posts have addressed MySQL parameters, like Alexander’s blog MySQL 5.7 Performance Tuning Immediately After Installation. That post remains highly relevant for the latest versions of MySQL, 5.7 and 8.0. Here we will focus more on the Linux operating system parameters that can affect database performance.

Server and Operating System

Here are some Linux parameters that you should check and consider modifying if you need to improve database performance.

…

Percona announces the release of Percona XtraDB Cluster 5.7.22-29.26 (PXC) on June 29, 2018. Binaries are available from the downloads section or our software repositories.

Percona XtraDB Cluster 5.7.22-29.26 is now the current release, based on the following:

• Percona Server for MySQL 5.7.22
• Galera/Codership WSREP API Release 5.7.21
• Galera Replication library 3.23

Deprecated

The following variables …

Kubernetes, and its most popular distribution OpenShift, receives a lot of interest as a container orchestration platform. However, databases remain a foreign entity, primarily because of their stateful nature, since container orchestration systems prefer stateless applications. That said, there has been good progress in support for StatefulSet applications and persistent storage, to the extent that it might be already comfortable to have a production database instance running in Kubernetes. With this in mind, we’ve been looking at running Percona XtraDB Cluster in Kubernetes/OpenShift.

While there are already many examples on the Internet of how to start a single MySQL instance in Kubernetes, for serious usage we need to provide:

• High Availability: how can we guarantee availability …

Why do I spend time blogging about security frameworks? Because, although there are some resources available on the Web, none apply to Percona XtraDB Cluster (PXC) directly. Actually, I rarely encounter a MySQL setup where SELinux is enforced and never when Percona XtraDB Cluster (PXC) or another Galera replication implementation is used. As we’ll see, there are good reasons for that. I originally thought this post would be a simple “how to” but it ended up with a push request to modify the SST script and a few other surprises.

Some context

These days, with all the major security breaches of the last few years, the importance of security in IT cannot be highlighted enough. For that reason, …

Percona announces the release of Percona XtraDB Cluster 5.6.40-26.25 (PXC) on June 20, 2018. Binaries are available from the downloads section or our software repositories.

Percona XtraDB Cluster 5.6.40-26.25 is now the current release, based on the following:

• Percona Server for MySQL 5.6.40
• Galera/Codership WSREP API Release 5.6.39
• Galera Replication library 3.23

All Percona software is open-source and free. …

Including setting up Percona XtraDB Cluster with ProxySQL and PMM

Please join Percona’s Architect, Tibi Köröcz as he presents Percona XtraDB Cluster 5.7 Tutorial Part 2 on Wednesday, June 20th, 2018, at 7:00 am PDT (UTC-7) / 10:00 am EDT (UTC-4).

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Never used Percona XtraDB Cluster before? This is the webinar for you! In this 45-minute webinar, we will introduce you to a fully functional Percona XtraDB Cluster.

This webinar will show you how to install Percona XtraDB Cluster with ProxySQL, and …