Join Percona Chief Evangelist Colin Charles as he covers happenings, gives pointers and provides musings on the open source database community.

Have you registered for Percona Live already? The tutorial grid, the schedules for day 1 and day 2 are pretty amazing, and there is even an extra track being added, for a total of 10 concurrent/parallel tracks during day 1 & day 2. If you submitted a talk and it didn’t get accepted (competition was high), you should have received a discount code to register for the event.

I plan to write more dedicated blog posts around M|18 and the MariaDB Developer’s …

Percona announces the release of Percona XtraDB Cluster 5.6.39-26.25 (PXC) on February 26, 2018. Binaries are available from the downloads section or our software repositories.

Percona XtraDB Cluster 5.6.39-26.25 is now the current release, based on the following:

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

Starting from this release, Percona XtraDB …

In this blog post, I’ll look at how to make Percona XtraDB Cluster and SELinux work when used together.

Recently, I encountered an issue with Percona XtraDB Cluster startup. We tried to setup a three-node cluster using Percona XtraDB Cluster with a Vagrant CentOS box, but somehow node2 was not starting. I did not get enough information to debug the issue in the donor/joiner error log. I got only the following error message:

2018-02-08 16:58:48 7910 [Note] WSREP: Running: 'wsrep_sst_xtrabackup-v2 --role 'joiner' --address '192.168.100.20' --datadir '/var/lib/mysql/' --defaults-file '/etc/my.cnf' --defaults-group-suffix '' --parent '7910' --binlog 'mysql-bin' '
2018-02-08 16:58:48 7910 [ERROR] WSREP: Failed to …

What if we tell you that there is a sure way to get IST not SST for node rejoins? You can guarantee that a new node rejoins using IST. Sound interesting? Keep reading.

Normally when a node is taken out of the cluster for a short period of time (for maintenance or shutdown), gcache on other nodes of the cluster help donate the missing write-set(s) when the node rejoins. This approach works if you have configured a larger gcache, or the downtime is short enough. Both approaches aren’t good, especially for a production cluster. Also, a larger gcache for the server lifetime means blocking larger disk-space when the same job can be done with relative smaller disk-space.

Re-configuring gcache, on a potential DONOR node before downtime requires a node …

Percona announces the release of Percona XtraDB Cluster 5.7.20-29.24 (PXC) on January 26, 2018. Binaries are available from the downloads section or our software repositories.

NOTE: Due to new package dependency,
Ubuntu/Debian users should use apt-get dist-upgrade, apt upgrade, or apt-get install percona-xtradb-cluster-57 to upgrade.

Percona XtraDB Cluster 5.7.20-29.24 is now the current release, based on the following:

• …

Recently, I was working with one of our customer and this is what their requirement as they want to automate this process for converting galera node to async slave and make async slave to galera node without shutting down any server. ———- Here are the steps for how to do that. I assumes that you already have working 3 nodes galera cluster if not, then for the testing purpose you can create it from my previous post. setup-three-nodes-mariadb-galera-cluster-on-single-server-with-mysql-sandbox ———- Btw, there is no matter how many nodes you have. Now, create one test1 table and add 3 records in galera cluster.

MariaDB [nil]> select * from test1;
+------+-----------+
| id   | name      |
+------+-----------+
|    1 | nilnandan |
|    2 | joshi     |
|    3 | niljoshi  |
+------+-----------+ …

Percona announces the release of Percona XtraDB Cluster 5.6.38-26.23 (PXC) on January 24, 2018. Binaries are available from the downloads section or our software repositories.

Percona XtraDB Cluster 5.6.38-26.23 is now the current release, based on the following:

• Percona Server for MySQL 5.6.38
• Galera/Codership WSREP API Release 5.6.38
• Galera Replication library 3.21

All Percona software is open-source and free. …

In this blog, we’ll look at how the hidepid options for /proc and Percona XtraDB Cluster can fight with one another.

One of the things I like about consulting at Percona is the opportunity to be exposed to unusual problems. I recently worked with a customer having issues getting SST to work with Percona XtraDB Cluster. A simple problem you would think. After four hours of debugging, my general feeling was that nothing made sense.

I added a bash trace to the SST script and it claimed MySQL died prematurely:

[ -n '' ]]
+ ps -p 11244
+ wsrep_log_error 'Parent mysqld process (PID:11244) terminated unexpectedly.'
+ wsrep_log '[ERROR] Parent mysqld process (PID:11244) terminated unexpectedly.'
++ date '+%Y-%m-%d %H:%M:%S'
+ local readonly 'tst=2017-11-28 22:02:46'

At the same time, from the MySQL error log MySQL was …

In this blog, we will answer questions from our webinar on Percona XtraDB Cluster 101.

Recently (7 Dec 2017) I presented a webinar about Percona XtraDB Cluster 101. Firstly, thanks to all the attendees: we had a great webinar with quite some interesting questions and feedback.

Through this blog, I’ll answer most of the questions that were raised during the webinar.

Q. How does the need for the acknowledgment from other nodes affect the speed of writes?

A. There are two parts to replication: delivering a transaction (including acknowledgment) and applying the transaction. …

In this blog post, we’ll look at how sequence numbers work in Percona XtraDB Cluster.

Introduction

Percona XtraDB Cluster uses multiple sequence numbers (seqno), each having a special role to play. Let’s try to understand the significance of each sequence number.

global_seqno

An active Percona XtraDB Cluster cluster has multiple write-sets (transactions) generated from one or more nodes. These transactions then get replicated to other nodes of the cluster. Each write-set/transaction should have a unique identity across the cluster. global_seqno helps serve this identity. Given write-set will have the same global_seqno on …