Apologies for the silly title, but the issue is a real one, even though it is not a new thing. Schema upgrades are not an ordinary operation in Galera. For the subject at hand, the bottom line is: under the default Total Order Isolation (TOI) method, “the cluster replicates the schema change query as a statement before its execution.” What this means in practice is that a DDL issued in one node is replicated to other nodes in the cluster before it is even executed in the source node, let alone completed successfully.

As a result of this, it may fail in one node and be successful in another, and this without raising loud alerts or stopping nodes to protect against data inconsistency. This is not a bug in itself but rather a compromise of design. With new changes in MySQL and the …

Codership is pleased to announce a new Generally Available (GA) release of the multi-master Galera Cluster for MySQL 5.6, 5.7 and 8.0, consisting of MySQL-wsrep 5.6.51 (release notes, download), 5.7.33 (release notes, download) and 8.0.23 (release notes, download) with Galera replication library 3.33 ( …

Codership is pleased to announce a new Generally Available (GA) release of the multi-master Galera Cluster for MySQL 5.6, 5.7 and 8.0, consisting of MySQL-wsrep 5.6.49 (release notes, download), 5.7.31 (release notes, download), and 8.0.21 (release notes, download) with Galera Replication library …

While we have documented how you might consider Monitoring a Cluster with Galera Manager, we’d also like to take you through a bit more of what is available, before our webinar this week. Please signup for a live demo from install to deployment and management.

You might be used to SHOW GLOBAL STATUS LIKE 'wsrep_%'; from the command line, but why not take a look at all of this on a graph, over time, within the GUI of the Galera Manager? What happens when you feel a node is getting overwhelmed? You tend to check wsrep_flow_control_paused, which returns the percentage of time the node was paused because of Flow Control (normally you do this after a FLUSH STATUS however now you …

A blog series about ProxySQL and Galera…

This post is the first of a series of blogposts on how to easily use ProxySQL to scale-out your application’s database workload on a Galera cluster. This series will explore the main concepts in configuring ProxySQL for Galera across three articles as follows:

– A first introductory post describing the minimal configuration needed for ProxySQL to monitor and manage a Galera Cluster.
– A second post describing how to setup a read/write split configuration for our Galera Cluster, using ProxySQL query rules.
– A third and final post with examples on specific cluster configuration options and more detailed explanations on why and how ProxySQL changes the nodes states based on configuration changes and monitored variables. Requirements

To illustrate how to configure ProxySQL for a Galera Cluster we will use a sample Galera Cluster …

I got this question on the “How to Avoid Pitfalls in Schema Upgrade with Percona XtraDB Cluster (PXC)” webinar and wanted to answer it in a separate post.

Will RSU have an effect on GTID consistency if replication PXC cluster to another cluster?

Answer for this: yes and no.

Galera assigns its own GTID for the operations, replicated to all nodes of the cluster. Such operations include DML (

INSERT/UPDATE/DELETE

 ) on InnoDB tables and DDL commands, executed with default TOI method. You can find more details on how GTIDs work in the Percona XtraDB Cluster in this blog post.

However, DDL commands, executed with RSU method, are …

Codership is pleased to announce a new Generally Available (GA) release of the multi-master Galera Cluster for MySQL 5.6 and 5.7, consisting of MySQL-wsrep 5.6.48 (release notes, download) and MySQL-wsrep 5.7.30 (release notes, download) with a new Galera Replication library 3.30 (release notes, download), implementing wsrep API version 25. This release incorporates all changes to MySQL 5.6.48 and 5.7.30 respectively, making it a MySQL High Availability solution.

A highlight of this release is that with MySQL 5.7.30, you will now have access to using the Percona audit log plugin, which will help with monitoring and logging connection and query activity that has been performed on specific servers. This implementation is provided as an alternative to the MySQL Enterprise Audit Log Plugin.

The Galera Replication library 3.30 has an enhancement to ensure that upon GCache recovery, all available space will be reclaimed in the …

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 …

We recently covered Installing Galera Cluster 4 with MySQL 8 on Ubuntu 18.04 , the new Galera version for MySQL High Availability. We got a request to see if we would be able to install it on Amazon Linux 2, and the short answer is yes, we are able to deploy Galera Cluster on Amazon Linux 2.

We have even published Installing a Galera Cluster on AWS guide for Geo-distributed MySQL Multi-master clustering which covers how to install a 3-node Galera Cluster on CentOS 7 to achieve disaster recovery . It turns out, Amazon Linux 2 tends to be quite compatible with this article ( …

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 …