MySQL Replication is very simple to set up. In this post I’ll discuss its importance and five handy tools for monitoring and managing MySQL replication.

What is MySQL Replication? It’s the process of copying the (real-time events) data from one master instance to another slave instance and maintaining the redundant consistent data in a different machine. This enables a distributed database system that shares the same level of information.

In MySQL the replication works based on the three threads as shown below.

1) I/O thread on the slave server:  To start on receiving replication events, an I/O thread starts on the slave server and connects to the master server.

2) Master connection handler thread:  As a connection handier, master starts a thread whenever a replication slave connects to a master. The master server sends the events from its binary log file to the slave I/O thread, notifying slave …

Percona is glad to announce the new release of Percona XtraDB Cluster 5.6 on March 5th 2015. Binaries are available from downloads area or from our software repositories.

Based on Percona Server 5.6.22-72.0 including all the bug fixes in it, Galera Replicator 3.9, and on Codership wsrep API 25.8, Percona XtraDB Cluster 5.6.22-25.8 is now the current …

Percona is glad to announce the release of Percona Server 5.6.22-72.0 on February 6, 2015. Download the latest version from the Percona web site or from the Percona Software Repositories.

Based on MySQL 5.6.22, including all the bug fixes in it, Percona Server 5.6.22-72.0 is the current GA release in the Percona Server 5.6 series. Percona Server is open-source and free – and …

You might have encountered situations where you had to kill some specific select queries that were running for long periods and choking the database. This post will go into more detail with an example of report query offloading.

Report query (select) offloading to a slave server is a common practice to reduce the workload of the master DB server. The long running selects will be executed in the slave for report generation. I have observed in many cases where the slave used to get delayed or the slave DB encounters a slowdown due to some heavy long-running orphaned selects from some wrong reports.

There are two main ways to kill queries in MySQL: 1. use custom scripts that match on a regular expression, or 2. use a tool written and supported by Percona that is designed to kill queries based on matching conditions. Below is one script that will help you to kill those queries. The script will take the process list from MySQL and …

Percona is pleased to announce the availability of Percona Toolkit 2.2.12.  Released on November 14, Percona Toolkit is a collection of advanced command-line tools to perform a variety of MySQL server and system tasks that are too difficult or complex for DBAs to perform manually. Percona Toolkit, like all Percona software, is free and open source.

This release is the current GA (Generally Available) stable release in the 2.2 series. Downloads are available here and from the Percona Software …

Percona is pleased to announce the availability of Percona Toolkit 2.2.11.  Released on Sept. 25, Percona Toolkit is a collection of advanced command-line tools to perform a variety of MySQL server and system tasks that are too difficult or complex for DBAs to perform manually. Percona Toolkit, like all Percona software, is free and open source.

This release contains bug fixes for pt-query-digest, pt-mysql-summary, pt-stalk, as well as other tools and is the current GA (Generally Available) stable release in the 2.2 series. Downloads are available here and from the  …

When a write query is sent to Percona XtraDB Cluster all the nodes store the writeset on a file called gcache. By default the name of that file is galera.cache and it is stored in the MySQL datadir. This is a very important file, and as usual with the most important variables in MySQL, the default value is not good for high-loaded servers. Let’s see why it’s important and how can we calculate a correct value for the workload of our cluster.

What’s the gcache?
When a node goes out of the cluster (crash or maintenance) it obviously stops receiving changes. When you try to reconnect the node to the cluster the data will be outdated. The joiner node needs to ask a donor to send the changes happened during the downtime.

The donor …

Percona is glad to announce the new release of Percona XtraDB Cluster 5.5 on September 5th 2014. Binaries are available from downloads area or from our software repositories.

Based on Percona Server 5.5.39-36.0 including all the bug fixes in it, Galera Replicator 2.11, and on …

Percona is glad to announce the new release of Percona XtraDB Cluster 5.6 on September 1st 2014. Binaries are available from downloads area or from our software repositories.

Based on Percona Server 5.6.20-68.0 including all the bug fixes in it, Galera Replicator 3.7, and on …

Percona is glad to announce the release of Percona Server 5.6.20-68.0 on August 29, 2014. Download the latest version from the Percona web site or from the Percona Software Repositories.

Based on MySQL 5.6.20, including all the bug fixes in it, Percona Server 5.6.20-68.0 is the current GA release in the Percona Server 5.6 series. All of Percona’s software is open-source and …