July 26, 2014

Monitoring MySQL flow control in Percona XtraDB Cluster 5.6

Monitoring flow control in a Galera cluster is very important. If you do not, you will not understand why writes may sometimes be stalled. Percona XtraDB Cluster 5.6 provides 2 status variables for such monitoring: wsrep_flow_control_paused and wsrep_flow_control_paused_ns. Which one should you use? What is flow control? Flow control does not exist with regular MySQL replication, […]

A schema change inconsistency with Galera Cluster for MySQL

I recently worked on a case where one node of a Galera cluster had its schema desynchronized with the other nodes. And that was although Total Order Isolation method was in effect to perform the schema changes. Let’s see what happened. Background For those of you who are not familiar with how Galera can perform […]

Managing shards of MySQL databases with MySQL Fabric

This is the fourth post in our MySQL Fabric series. In case you’re joining us now, we started with an introductory post, and then discussed High Availability (HA) using MySQL Fabric here (Part 1) and here (Part 2). Today we will talk about how MySQL Fabric can help you scale out MySQL databases with sharding. Introduction At the […]

Using MySQL triggers and views in Amazon RDS

I recently had an opportunity to migrate a customer from a physical server into Amazon’s RDS environment. In this particular case the customers’ platform makes extensive use of MySQL triggers and views.  I came across two significant issues that prevented me from following Amazon’s documentation, which basically states “use mysqldump” but doesn’t call out a […]

Semi-Sync replication performance in MySQL 5.7.4 DMR

I was interested to hear about semi-sync replication improvements in MySQL’s 5.7.4 DMR release and decided to check it out.  I previously blogged about poor semi-sync performance and was pretty disappointed from semi-sync’s performance across WAN distances back then, particularly with many client threads. The Test The basic environment of these tests was: AWS EC2 […]

A conversation with 5 Facebook MySQL gurus

Facebook, the undisputed king of online social networks, has 1.23 billion monthly active users collectively contributing to an ocean of data-intensive tasks – making the company one of the world’s top MySQL users. A small army of Facebook MySQL experts will be converging on Santa Clara, Calif. next week where several of them are leading […]

The power of MySQL’s GROUP_CONCAT

In the very early days of Percona Vadim wrote very nice post about GROUP_CONCAT. But I want to show you a bit more about it. When is GROUP_CONCAT useful? Usually while working with Support customers I recommend it when you have aggregation of many-to-many info. It makes the view simpler and more beautiful and it […]

Advanced MySQL Query Tuning: Webinar followup Q&A

Thanks to all who attended my “MySQL Query Tuning” webinar on July 24.  If you missed it, you can you can download the slides and also watch the recorded video. Thank you for the excellent questions after the webinar as well. Query tuning is a big topic and, due to the limited time, I had […]

MySQL and Hadoop integration

Dolphin and Elephant: an Introduction This post is intended for MySQL DBAs or Sysadmins who need to start using Apache Hadoop and want to integrate those 2 solutions. In this post I will cover some basic information about the Hadoop, focusing on Hive as well as MySQL and Hadoop/Hive integration. First of all, if you […]

MySQL Webinar: Percona XtraDB Cluster Operations, June 26

Percona XtraDB Cluster (PXC) was released over a year ago and since then there has been tremendous interest and adoption.  There’s plenty of talks that explain the fundamentals of PXC, but we’re starting to reach a threshold where it’s easier to find folks with PXC in production and such the need for more advanced talks […]