With an ear to the interwebs, you’ll hear a few things about Docker. Docker is an open platform for developers and sysadmins to build, ship, and run distributed applications. In this blog post, I’m going to outline a very basic example of how to use Sphinx from within a Docker container. What is Docker? This [...]

Yay! My first blog post! As long as at least 1 person finds it useful, I’ve done my job. Recently, one of my long-term clients was noticing that while their INSERTs were succeeding, a particular column counter was not incrementing. A quick investigation determined the column was of type int(11) and they had reached the maximum value of 2147483647. We fixed this by using pt-online-schema-change to change the column to int(10) unsigned, thus allowing values up to 4294967295.

My client was now concerned about all his other integer-based columns and wanted me to check them all. So I wrote a quick-n-dirty script in Go to check all integer-based columns on their current value compared to the maximum allowed for that column type.

You …

MySQL Cluster enables high availability by storing data replicas on multiple hosts. MySQL Cluster maintains connections between data nodes by using high-speed interconnects over TCP/IP - standard or direct connections - or SCI (Scalable Coherent Interface) sockets.

To learn more about MySQL Cluster, take the MySQL Cluster training course.

This course is currently scheduled for the following locations:

After MySQL 5.1 was released work started on MySQL 5.2, but then this was renamed to MySQL 6.0. There were many new features introduced in 6.0. But then stabilizing this branch became as huge task. Eventually the decision was made to start of with a stable branch and backport the new features from 6.0. This is how many of the 6.0 features landed in 5.5 and 5.6.

So let's see which features 6.0 brought and were they landed. I'll use the What Is New in MySQL 6.0 section of the MySQL 6.0 Reference Manual for this.

• The Falcon storage engine. This never landed anywhere as far as I know. It's not even included in the …

Critical MySQL 5.6 bug: any user with GRANT privileges can unwillingly cause all replicas to break

The latest major release of MySQL brought us a lot of new and exciting features. As always, new features come with brand new bugs waiting to bite you in the least expected way.

I was implementing a monitoring system for a client and needed to create a new dedicated user. I went ahead and granted the usual basic privileges but later, I discovered that this user also needed the REPLICATION CLIENT privilege because the monitoring needed it to check for replication status.

No big deal, let’s grant this as well. Unfortunately I did not get it right at first:

grant replication client on database.* to user@’10.%';
ERROR 1221 (HY000): Incorrect usage of DB GRANT and GLOBAL PRIVILEGES

Ouch! My bad! This is a global privilege and I should grant it on “*.*”:

grant replication client on *.* to …

Managing many hosts is quite challenging task. There are many tools to solve the problem. My favorite is pdsh.

Running a command across a set of hosts is as simple as following:

# pdsh -w 192.168.177.[201-208] -R ssh reboot

Together with dshbak (which is a part of pdsh package) you can do even cooler things. Like, check which systems have yum:

# pdsh -w 192.168.177.[201-208] -R ssh "which yum" | dshbak -c
----------------
192.168.177.[201-203]
----------------
/usr/bin/yum 

Or which systems run older version of MySQL

# pdsh -w 192.168.177.[201-208] -R ssh "mysql -e \"SHOW VARIABLES LIKE 'version'\""  | dshbak -c
----------------
192.168.177.[201-203]
----------------
Variable_name   Value
version 5.6.19
----------------
192.168.177.[204-208]
----------------
Variable_name   Value
version 5.5.38

To make pdsh …

MaxScale, the pluggable proxy for MySQL databases has just gone beta. With this new release comes a number of new features that improve the usability, functionality and versatility of MaxScale. Here are  a few of the things that have now become available with MaxScale 1.0 Beta.Read/Write Splitter Routing ModuleA number of enhancements have been made to the Read/Write splitter routing module for MaxScale

• Support for prepared statements
• Fault tolerance for read operations via multiple slaves
• Configurable load balancing methods
• Integration with slave replication lag monitoring to cap the acceptable lag
• Ability to weight the load distribution mechanism

Prepared StatementsThe preparation stage is now correctly recognised and distributed to all servers within a session that might need to execute these statements at a later date. The execution is then routed to an …

Percona XtraDB Cluster (PXC) is a high availability and high scalability, solution for MySQL clustering. Percona Server, Percona Xtrabackup and Galera library for high availability integrated together as PXC. It provides synchronous, multi-master, and parallel replication. All the nodes of this cluster are ready to serve read/write request simultaneously.

VMs used for illustration. Here, I've used 1 centos node and 2 ubuntu nodes. In real world don't mix different OS. This is just for testing purpose. All nodes should be of the same configuration hardware/software.

1 Centos12        192.168.56.12           node1
2 Ubuntu13        192.168.56.13           node2
3 Ubuntu14        192.168.56.14           node3

Adding repo's to the requisite OS

Centos/Redhat:

$ yum install …

Percona XtraDB Cluster (PXC) is a high availability and high scalability, solution for MySQL clustering. Percona Server, Percona Xtrabackup and Galera library for high availability integrated together as PXC. It provides synchronous, multi-master, and parallel replication. All the nodes of this cluster are ready to serve read/write request simultaneously.

VMs used for illustration. Here, I've used 1 centos node and 2 ubuntu nodes. In real world don't mix different OS. This is just for testing purpose. All nodes should be of the same configuration hardware/software.

1 Centos12        192.168.56.12           node1
2 Ubuntu13        192.168.56.13           node2
3 Ubuntu14        192.168.56.14           node3

Adding repo's to the requisite OS

Centos/Redhat:

$ yum install …

Percona XtraDB Cluster 5.6 Setup Krishna Prajapati Fri, 07/04/2014 - 15:21 Percona XtraDB Cluster 5.6 Setup

Percona XtraDB Cluster (PXC) is a high availability and high scalability, solution for MySQL clustering. Percona Server, Percona Xtrabackup and Galera library for high availability integrated together as PXC. It provides synchronous, multi-master, and parallel replication. All the nodes of this cluster are ready to serve read/write request simultaneously.

VMs used for illustration. Here, I've used 1 centos node and 2 ubuntu nodes. In real world don't mix different OS. This is just for testing purpose. All nodes should be of the same configuration hardware/software.

1 Centos12 …