April 18, 2014

Disconnecting a replication slave is easier with MySQL 5.5+ (RESET SLAVE vs. RESET SLAVE ALL)

It’s not uncommon to promote a server from slave to master. One of the key things to protect your data integrity is to make sure that the promoted slave is permanently disconnected from its old master. If not, it may get writes from the old master, which can cause all kinds of data corruption. MySQL […]

Percona XtraDB Cluster 5.6.15-25.5 is now available

Percona is glad to announce the new release of Percona XtraDB Cluster 5.6 on March 20th 2014. Binaries are available from downloads area or from our software repositories. Based on Percona Server 5.6.15-63.0 including all the bug fixes in it, Galera Replicator 3.4 and on Codership wsrep API 25.5 is now the current General Availability […]

10 MySQL settings to tune after installation

When we are hired for a MySQL performance audit, we are expected to review the MySQL configuration and to suggest improvements. Many people are surprised because in most cases, we only suggest to change a few settings even though hundreds of options are available. The goal of this post is to give you a list […]

Automatic replication relaying in Galera 3.x (available with PXC 5.6)

A decade ago MySQL folks were in love with the concept of a relay slave for MySQL high availability across data centers.  A relay is a single slave in a remote data center that receives replication from the global master and, in turn, replicates to all the other local slaves in that data center.  This saved […]

Percona XtraDB Cluster 5.5.34-23.7.6 is now available

Percona is glad to announce the release of Percona XtraDB Cluster 5.5.34-23.7.6 on November 4, 2013. Binaries are available from the downloads area or from our software repositories. Bugs Fixed: Fixed the issues with upgrade on Debian caused by debian-start script. Bug fixed #1112363. Adding the AUTO_INCREMENT column to a table would result in data […]

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 […]

Measuring Max Replication Throughput on Percona XtraDB Cluster with wsrep_desync

Checking throughput with async MySQL replication Replication throughput is the measure of just how fast the slaves can apply replication (at least by my definition).  In MySQL async replication this is important to know because the single-threaded apply nature of async replication can be a write performance bottleneck.  In a production system, we can tell […]

Innotop: A real-time, advanced investigation tool for MySQL

GUI monitoring tools for MySQL are not always suitable for all our needs or situations. Most of them are designed to provide historical views into what happens to our database over time rather then real-time insight into current MySQL server status. Excellent free tools for this include Cacti, Zabbix, Ganglia, Nagios, etc. But each of […]

5 reasons why MySQL replication lag is flapping between 0 and XXXXX

Working day to day with Percona Remote DBA customers, we have been facing an issue from time to time when MySQL replication lag is flapping between 0 and XXXXX constantly – i.e. Seconds_Behind_Master is 0 for a few secs, then it’s like 6287 or 25341, again 0 and so on. I would like to note […]

Enabling crash-safe slaves with MySQL 5.6

Being able to configure slaves to be crash-safe is one of the major improvements of MySQL 5.6 with regards to replication. However we noticed confusion on how to enable this feature correctly, so let’s clarify how it should be done. In short 1. Stop MySQL on slave 2. Add relay_log_info_repository = TABLE and relay_log_recovery = […]