Today I gave a presentation on “Read/Write Splitting with PHP” for Percona Webinars.  If you missed it, you can still register to view the recording and my slides.

Thanks to everyone who attended, and especially to folks who asked the great questions.  I answered as many as I could during the session, but here are all the questions with my complete answers:

Q: I wasn’t able to start up the webinar until it was 20 minutes in progress. Is it possible to get a recording once it is over?

A: Yes, we will email a link to all webinar attendees with a recording of the webinar and a link to the slides within 24 hours.  Folks who did not attend the webinar can also visit the webinar …

I’ll be presenting a webinar next Wednesday, January 23 at 10 a.m. (Pacific Time), about issues application developers should think about for scaling out read-query traffic using multiple MySQL instances in a replication pair.

Specifically, about the care we have to take because replication is asynchronous.  This means the slave  may not have current data at all times, so an application must choose to query the slave or the master dynamically.  As much as possible, we’d like to automate this choice so that application developers can be the most productive.

Please join me for this webinar by registering here: http://www.percona.com/webinars/readwrite-splitting-mysql-and-php

The post Webinar on …

There have been a number of comments that Amazon RDS does not allow users access to MySQL replication capabilities (for example here and here).  This is a pity. Replication is one of the great strengths of MySQL and the lack of it is a show-stopper for many users.  As of the latest build of Tungsten Replicator half of this problem is on the way to being solved. You can now set up real-time replication from an external MySQL master into an Amazon RDS instance.

In the remainder of this article I will explain how to set up Tungsten replication to an Amazon RDS slave, then add a few thoughts …

We have started a new series of webinars at Continuent that we call Tungsten University.  They provide education on Tungsten clustering and replication in handy one-hour chunks.  These are not sales pitches.  Our goal is to provide accessible education about setting up and operating Tungsten without any marketing fluff.

The first Tungsten University webinar entitled "Configure & provision Tungsten clusters" will take place on Thursday January 17th at 10:00 PST.  It will show you how to set up a cluster in Amazon EC2.  There will be a repeat on January 22nd at 15:00 GMT.  We usually record webinars, so you can look at them later as well. 
You do not have to be a customer to attend these webinars, …

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 even find it. So, I decided to write one now.

Of course, there are many aspects of MySQL replication, but my main focus will be the logistics – how replication events are written on the master, how they are transferred to the replication slave and then how …

Global Transaction Identifiers (GTIDs) are one of the key replication enhancements in MySQL 5.6. GTIDs make it simple to track and compare replication across a master - slave topology. This enables:

- Much simpler recovery from failures of the master,

- Introduces great flexibility in the provisioning and on-going management of multi-tier or ring (circular) replication topologies.

A new on-demand MySQL 5.6 GTID webinar delivered by the replication engineering team is now available, providing deep insight into the design and implementation of GTIDs, and how they enable users to simplify MySQL scaling and HA. The webinar covers:

- Concepts: What is a GTID? How does the …

MySQL 5.6 seems to be ready for GA. I have no inside information about it, but from some clues collected in various places I feel that the release should not be far away. Thus, it's time for some serious testing, and for that purpose I have worked at updating MySQL Sandbox with some urgent features.

I have just released MySQL Sandbox 3.0.28, with more support for MySQL 5.6. Notably in this release, there is suppression of MySQL 5.6 annoying verbosity, additional suppression of more annoying warnings ( actually a bug) when using empty passwords on …

I got some very good comments/questions on my previous post on MariaDB global transaction ID, from Giuseppe and Robert (of Tungsten fame). I thought a follow-up post would be appropriate to answer and further elaborate on the comments, as the points they raise are very important and interesting.

(It also gives me the opportunity to explain more deeply a lot of interesting design decisions that I left out in the first post for the sake of brevity and clarity.)

On crash-safe slave

One of the things I really wanted to improve with global transaction ID is to make the replication slaves more crash safe with respect to their current replication state. This state is mostly persistently stored information about which event(s) were last executed on the slave, so that after a server restart the slave will know from which point in the master binlog(s) …

The main goal of global transaction ID is to make it easy to promote a new master and switch all slaves over to continue replication from the new master. This is currently harder than it could be, since the current replication position for a slave is specified in coordinates that are specific to the current master, and it is not trivial to translate them into the corresponding coordinates on the new master. Global transaction ID solves this by annotating each event with the global transaction id which is unique and universal across the whole replication hierarchy.

In addition, there are at least two other main goals for MariaDB global transaction ID:

1. Make it easy to setup global transaction ID, and easy to provision a new slave into an existing replication hierarchy.
2. Fully support …

The  MariaDB Foundation announcement spawned some interesting commentary about the state of open source databases.  One recent headline cited the "beleaguered MySQL community." Beleaguered is a delightful adjective.  The OED tells us that it means beset, invested, or besieged.  Much as I like the word, I do not think it is an accurate or useful description of the MySQL community.  This article and others like it miss the point of what is happening to MySQL and its users.

Let's start by disproving that the notion that the MySQL community is beleaguered.  I don't …