In this blog, I am going to explain the different ways of electing the PRIMARY node in MySQL group replication. Before MySQL 8.0.2, primary election was based on the member’s UUID, with the lowest UUID elected as the new primary in the event of a failover.

From MySQL 8.0.2: We can select the node to be promoted as a PRIMARY using the server weight ( group_replication_member_weight ). This can be achieved during the failure of the current primary node.

From MySQL 8.0.12: We can promote any node as a PRIMARY using the function “group_replication_set_as_primary”. This can be set anytime without any failures of nodes.

Scenario:

 I have installed the 3 node group replication cluster. I am using Percona Server for MySQL 8.0.22.

mysql> select …

The aim of Percona Kubernetes Operator for Percona XtraDB Cluster is to be a special type of controller introduced to simplify complex deployments. The Operator extends the Kubernetes API with custom resources. The Operator solution is using Percona XtraDB Cluster (PXC) behind the hood to provide a highly available, resilient, and scalable MySQL service in the Kubernetes space. 

This solution comes with all the advantages/disadvantages provided by Kubernetes, plus some advantages of its own like the capacity to scale reads on the nodes that are not Primary.

Of course, there are some limitations like the way PXC handles DDLs, which may impact the service, but there is always a cost to pay to get something, expecting to have it all for free is unreasonable.     

In this context, we need to …

Percona Kubernetes Operator for Percona XtraDB Cluster comes with two different proxies, HAProxy and ProxySQL. While the initial version was based on ProxySQL, in time, Percona opted to set HAProxy as the default Proxy for the operator, without removing ProxySQL. 

While one of the main points was to guarantee users to have a 1:1 compatibility with vanilla MySQL in the way the operator allows connections, there are also other factors that are involved in the decision to have two proxies. In this article, I will scratch the surface of this why.

Operator Assumptions

When working with the Percona Operator, there are few things to keep in mind:

• Each deployment has to be seen as a single MySQL service as if a single MySQL instance
• The technology used to provide the service may change in time …

Today we are going to present you with another way to make a database copy between servers using our Percona XtraBackup utility.  What is the difference with many others existing on the web?  Not many, but they are interesting in terms of performance and availability.

We will combine the xbstream utility with the power of pigz and socat, to take advantage of the multi-processing in the case of having multiple processors, and at the same time, reduce the use of network bandwidth in cases where this component is a bottleneck.  So let’s explain each component:

socat: This stands for SOcket CAT. It is a utility for data transfer between two addresses.

What makes socat so versatile is the fact that an address can represent a network socket, any file descriptor, a Unix domain datagram or stream …

A lot of elements take part in a good backup strategy. Two of them are:

• Where to store your backups – Never on the same server. Preferable not in the same datacenter. Ideally far enough so you can restore in case of a natural disaster (region flood, extended local power outage, etc…).
• Retention period – The longer, the better.

Those points relate directly to costs. Storing a backup on an off-site facility cost money. Keeping the backups available to fulfill your retention period policy costs money.

The main cloud providers have different layers of storage often called Storage Class. Each layer has its own particularities and policies, but they come with an important factor – Cost!

We are happy to announce that starting at …

MySQL 5.7, alongside other many improvements, brought bulk load for creating an index (WL#7277 to be specific), which made ADD INDEX operations much faster by disabling redo logging and making the changes directly to tablespace files. This change requires extra care for backup tools. To block DDL statements on an instance, Percona Server for MySQL implemented LOCK TABLES FOR BACKUP. Percona XtraBackup (PXB) uses this lock for the duration of the backup. This lock does not affect DML statements.

MySQL 5.7 doesn’t have an option to block an instance against DDL and to allow all MDL’s. Thus, Percona XtraBackup has also implemented –lock-ddl-per-table. Before we go into other details, let’s understand how –lock-ddl-per-table works up to now:

1. PXB …

As you may know, MySQL 5.6 will reach EOL (“End of Life”) in February 2021. This means in about two months, there will be no more updates, and more importantly, no more security fixes for discovered vulnerabilities.     

You may be well ahead of the curve and have already updated to MySQL 5.7 or MySQL 8.0, or even better, migrated to Percona Server for MySQL, or maybe not. Perhaps it takes more time than anticipated to adjust your application to be compatible with MySQL 5.7 or higher, or maybe you planned to decommission your application, but life got in the way. Now the EOL date is looming, and there is just no way to decommission your last MySQL 5.6 instance in time.

We have great news for our MySQL Luddites! Percona is pleased to …

The benefits of jemalloc versus glibc memory allocator for use with MySQL have been widely discussed. With jemalloc (along with Transparent Huge Pages disabled) there is less memory fragmentation, and thus more efficient resource management of the server memory. For MySQL 5.6, installing jemalloc is enough to enable it when starting the MySQL process. However, for MySQL 5.7 and 8.0.X series, you will need to take a few extra steps.

Enabling jemalloc on Percona Server for MySQL

Installing the jemalloc package is simple for Percona. This is because the library is available on the Percona repository, which is available for both apt and yum package management:

…

How scheduler and script stand in supporting failover (Percona and Marco example) 

In part one of this series,  I had illustrated how simple scenarios may fail or have problems when using Galera native support inside ProxySQL. In this post, I will repeat the same tests but using the scheduler option and the external script.

The Scheduler

First a brief explanation about the scheduler.

The scheduler inside ProxySQL was created to allow administrators to extend ProxySQL capabilities. The scheduler gives the option to add any kind of script or application and run it at the specified interval of time. The scheduler was also the initial first way we had to deal with Galera/Percona XtraDB Cluster (PXC) node management in case of issues. 

…

How native ProxySQL stands in failover support (both v2.0.15 and v2.1.0)

In recent times I have been designing several solutions focused on High Availability and Disaster Recovery. Some of them using Percona Server for MySQL with group replication, some using Percona XtraDB Cluster (PXC). What many of them had in common was the use of ProxySQL for the connection layer. This is because I consider the use of a layer 7 Proxy preferable, given the possible advantages provided in ReadWrite split and SQL filtering. 

The other positive aspect provided by ProxySQL, at least for Group Replication, is the native support which allows us to have a very quick resolution of possible node failures.

ProxySQL has Galera …