July 24, 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 […]

Replication checksums in MySQL 5.6

MySQL 5.6 has an impressive list of improvements. Among them, replication checksums caught my attention as it seems that many people misunderstand the real added value of this new feature. I heard people think that with replication checksums, data integrity between the master and its replicas is now enforced. As we’ll see, it’s not that […]

How does MySQL Replication really work?

While we do have many blog posts on replication on our blog, such as on replication being single-threaded, on semi-synchronous replication or on estimating replication capacity, I don’t think we have one that covers the very basics of how MySQL replication really works on the high level. Or it’s been so long ago I can’t […]

Percona XtraDB Cluster (PXC): what about GRA_*.log files ?

How easy is it to identify and debug Percona XtraDB Cluster replication problem ? If you are using PXC, you may have already seen in your datadirectory several log files starting with GRA_ Those files correspond to a replication failure. That means the slave thread was not able to apply one transaction. For each of […]

read_buffer_size can break your replication

There are some variables that can affect the replication behavior and sometimes cause some big troubles. In this post I’m going to talk about read_buffer_size and how this variable together with max_allowed_packet can break your replication. The setup is a master-master replication with the following values: max_allowed_packet = 32M read_buffer_size = 100M To break the […]

Testing Percona Replication Manager (prm) with Vagrant

If you have recently attended some Percona Live events or if you have checked some slides from Yves Trudeau, you may have heard about Percona Replication Manager (PRM), a new high availability tool for MySQL. Percona Live DC 2012 Percona Live MySQL Conference & Expo 2012   PRM is an OCF Resource Agent for Corosync […]

How to convert MySQL’s SHOW PROFILES into a real profile

SHOW PROFILES shows how much time MySQL spends in various phases of query execution, but it isn’t a full-featured profile. By that, I mean that it doesn’t show similar phases aggregated together, doesn’t sort them by worst-first, and doesn’t show the relative amount of time consumed. I’ll profile the “nicer_but_slower_film_list” included with the Sakila sample […]

Making the impossible: 3 nodes intercontinental replication

In this post I want to show new possibilities which open with Percona XtraDB Cluster. We will create 3 nodes Cluster with nodes on different continents (Europe, USA, Japan) and each node will accept write queries. Well, you theoretically could create 3 node traditional MySQL ring replication, but this is not what you want to […]

Percona Replication Manager, a solution for MySQL high availability with replication using Pacemaker

The content of this article is outdated, look here for more up to date information. Over the last year, the frustration of many of us at Percona regarding issues with MMM has grown to a level where we started looking at other ways of achieving higher availability using MySQL replication. One of the weakness of […]

MySQL Limitations Part 1: Single-Threaded Replication

I recently mentioned a few of the big “non-starter” limitations Postgres has overcome for specific use cases. I decided to write a series of blog posts on MySQL’s unsolved severe limitations. I mean limitations that really hobble it for major, important needs — not in areas where it isn’t used, but in areas where it […]