Global Transactions Identifiers are one of the new features regarding replication in MySQL 5.6. They open up a lot of opportunities to make the life of DBAs much easier when having to maintain servers under a specific replication topology. However you should keep in mind some limitations of the current implementation. This post is the first one of a series of articles focused on the implications of enabling GTIDs on a production setup.

The manual describes very nicely how to switch to GTID-based replication, I won’t repeat it.

Basically the steps are:

• Make the master read-only so that the slaves can execute all events and be in sync with the master
• Change configuration for all servers and …

The MySQL Utilities Team is pleased to announce our latest release, version 1.2.1. This release contains many quality improvements and enhancements to the HA and Replication utilities. The following lists some of the most significant improvements.

• Improved transaction gathering algorithm for failover
  • Skips slaves that are already caught up
  • Ensures all transactions in the relay logs on the slaves are executed first
• External scripts in mysqlfailover and mysqlrpladmin now receive the old and new master information
• Improved demote master handling for switchover
• Improved connection error handling
• Quoting of tables and database names has been improved
• Login-path feature now reads port and socket

The utilities team continues to focus on improving usability, making features easier to use, and …

<< Previous Post: Advanced use of Global Transaction Identifiers

As we saw in my previous posts, Global Transaction Identifiers in MySQL 5.6 allow you to change the replication topology arbitrarily. You don't even need to specify the positions in the replication stream – when you turn on auto-positioning, the master automatically sends only those transactions that are missing on the slave.

When you do a fail-over, you want to make sure that the new master is up-to-date. For instance, consider the following scenario:
Server A is a master; B, C and …

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 …

In a previous post I showed how to implement multi-source round-robin replication in pure SQL using the tables that are needed for crash-safe replication. I also outlined a revised version of this approach in the Replication Tips & Tricks presentation I gave at MySQL Connect. This was, however, before the GTID (Global Transaction ID) implementation was done. Now that they are introduced, multi-source replication is even easier since you no longer have to keep track of the positions.

Figure 1. Tables for storing information about masters

CREATE TABLE my_masters (
    idx INT AUTO_INCREMENT,
    host CHAR(50) NOT NULL,
    port INT NOT NULL DEFAULT …

Not much to add really to the bug I’ve filed here: bug#67159.

Again this GTID stuff looks good, but seems to prevent changes in the configuration of performance_schema, which I think is not appropriate, especially as P_S now has lots of extra goodies and after 5.6 will surely have even more.

Not much to add really to the bug I’ve filed here: bug#67099.

I personally can think of some very nasty consequences of applying this on the slaves I manage, and the reason I’m posting the bug is that while I guess this is too late to fix in 5.6 as it’s effectively a new feature, I’m sure many sites may bump into this and be somewhat disappointed if they want to use the new GTID feature and have several slaves.  Hence, if the fix/feature has to go into MySQL 5.7 then I hope it goes in sooner rather than later. We will see.

Updated: 2013-09-19

I probably should have updated this earlier but it does seem that Oracle have taken these comments on board. See: WL6559.  It looks like they plan to do this for 5.7 which is good news. I’m really hoping …

A colleague, Kris, commented recently on a recent find I made on 5.6.7-rc1 which while not the end of the world does seem to severely limit the use of the new GTID features, or if nothing else make it a pain to use.

Today I found another related issue, when trying to check the syntax of one of the MySQL commands. That’s now reported as bug#67073.

All of these are sort of edge cases but do make 5.6 look a little rough round the edges, when the rest of the product is actually really good and a great improvement from The MySQL 5.5 GA version that everyone uses.  That’s really a shame.

I did report the Original problem as SR 3-6270525721 : MySQL 5.6.7-rc1, grants, replication and GTID cause problems, but of course that’s …

On Wednesday May 16th, we ran a webinar to provide an overview of all of the new replication features and enhancements that are previewed in the MySQL 5.6 Development Release – including Global Transaction IDs, auto-failover and self-healing, multi-threaded, crash-safe slaves and more.

Collectively, these new capabilities enable MySQL users to scale for next generation web and cloud applications.

Attendees posted a number of great questions to the MySQL developers, serving to provide additional insights into how these new features are implemented. So I thought it would be useful to post those below, for the benefit of those unable to attend the live webinar (note, you can listen to the On-Demand replay which is available now).

Before getting to the Q&A, there are a couple of other resources that maybe useful to …