Lets start by considering a scenario where records are being inserted in a single auto-increment table via different nodes of a multi-master cluster. One issue that might arise is ‘collision’ of generated auto-increment values on different nodes, which is precisely the subject of this article.

As the cluster is multi-master, it allows writes on all master nodes. As a result of which a table might get same auto-incremented values on different nodes on INSERTs. This issue is discovered only after the writeset is replicated and that’s a problem!

Galera cluster suffers with the similar problem.

Lets try to emulate this on a 2-node Galera cluster :

1) On node #1:

MariaDB [test]> CREATE TABLE t1(c1 INT AUTO_INCREMENT PRIMARY KEY, c2 INT)ENGINE=InnoDB;
Query OK, 0 rows affected (0.07 sec)

MariaDB [test]> START TRANSACTION;
Query OK, 0 rows affected (0.00 sec)

MariaDB [test]> INSERT INTO t1(c2) VALUES (1);
Query …

February 18, 2014 By Severalnines

Virtual Machines are great, and very useful when trying out new software. However, they might be an unnecessarily heavyweight solution when testing clusters, especially if these consist of multiple nodes running exactly the same software. Each VM runs a full-blown OS image. On the other hand, Linux Containers (LXC) are an efficient alternative to OS-level virtualization and can run multiple isolated systems on a single host. Docker is a wrapper around LXC, it automates the deployment of applications inside containers. 

A notable advantage if you run with Docker + LXC is you can run many containers on a single host. They all share the same OS as the host, and when possible, the same binaries. Deployment can be extremely fast. Using Docker could be a good method if you want to spin multiple Galera nodes within a single host. 

In this post, we will create MySQL Galera Cluster …

The MariaDB project is pleased to announce the immediate availability of MariaDB Galera Cluster 5.5.35. This is a Stable release.

See the Release Notes and Changelog for detailed information on this release and the Galera page in the MariaDB Knowledge Base for general information about MariaDB Galera Cluster.

Download MariaDB Galera Cluster 5.5.35

Release Notes …

This week I’ve been writing based on my linux.conf.au 2014 talk, which you can watch the recording of.

Also see Part 1, Part 2, Part 3 and Part 4. My feed feel off Planet MySQL for a bit so you may have missed those posts.

Now we head into the era of acquisitions… there have been a few in …

February 13, 2014 By Severalnines

Galera is slowly but surely establishing itself as a credible replacement for traditional MySQL master-slave architectures. 

The benefits are clear - a true multi-master InnoDB setup with built-in fail-over, potentially across data centers. 

But how do you migrate? Does the schema or application change? What are the limitations? Can migration be done online, without service interruption? What are the potential risks, and how to address those?

Webinar: Migrating to MySQL, MariaDB Galera and/or Percona XtraDB Cluster

Tuesday, March 11th 2014

Register now - Europe/MEA/APAC

Register now - North …

MariaDB 10.0.8 was recently released as RC ("Release Candidate"), and is available for download here:

https://downloads.mariadb.org/mariadb/10.0.8/

This is the first RC release of MariaDB 10.0. It is primarily a bug-fix and polishing release, and all features planned for MariaDB 10.0 GA are included in this release.

There were 6 notable changes in MariaDB 10.0.8:

1. InnoDB upgraded to version 5.6.14

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I have just implemented MASTER_GTID_WAIT() in MariaDB 10.0. This can be used to give a very elegant solution to the problem of stale reads in replication read-scaleout, without incuring the overheads normally associated with synchronous replication techniques. This idea came up recently in a discussion with Stephane Varoqui, and is similar to the concept of Lamport logical clock described in this Wikipedia article.

I wanted to describe this, hoping to induce people to test and maybe start using this, as it is a simple but very neat idea, actually.

A very typical use of MariaDB/MySQL …

The MariaDB project is pleased to announce the immediate availability of MariaDB 10.0.8. This is a Release Candidate release.

See the Release Notes and Changelog for detailed information on this release and the What is MariaDB 10.0? page in the MariaDB Knowledge Base for general information about the MariaDB 10.0 series.

Download MariaDB 10.0.8

Release Notes …

It's my pleasure to be presenting at SCaLE 12X on the subject of real-time data loading from MySQL to Hadoop.  This is the first public talk on work at Continuent that enables Tungsten Replicator to move transactions from MySQL to HDFS (Hadoop Distributed File System).  I will explain how replication to Hadoop works, how to set it up, and offer a few words on constructing views of MySQL data using tools like Hive.

As usual with replication everything we are doing on Hadoop replication is open source.  Builds and documentation will be publicly available …

MariaDB 5.5.35 was recently released (it is the latest MariaDB 5.5), and is available for download here:

https://downloads.mariadb.org/mariadb/5.5.35/

This is a maintenance release, and so there are not too many big changes of note. However, there are a couple items worth mentioning:

1. Includes all bugfixes and updates from: MySQL 5.5.35
2. Includes all bugfixes and updates from: XtraDB from Percona-Server-5.5.35-rel33.0

read more