Before Percona XtraBackup 2.1.7 and Percona XtraDB Cluster 5.6.15-25.3, rsync was the only SST method supporting GTID in the way that it was possible to move an asynchronous slave from one Galera node to another one (related bug).

Indeed, previous versions of Percona XtraBackup didn’t copy any binary log and due to that, moving the async slave to another master, just broke replication (when writes still happened).

Now with the latest version of Percona XtraBackup and Percona XtraDB Cluster, wsrep_sst_xtrabackup-v2 handles the last binlog sent from Percona XtraBackup and allows the move to another …

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 …

We are in the middle of switching to GTID based replication from the good old logfile & log position based replication.

But what is GTID? GTID is an abbreviation of ‘GLOBAL TRANSACTION ID’ what speaks for itself: each transaction of a mysql cluster got its globally unique transaction ID, and the DBA have not spend time with positioning slaves, as well as we don’t have to ‘freeze’ any of the servers because of a master failover. The only thing we have to care about: to know what server should be used as a replication master.

OK, what was the problem with the old file-based replication?

Check out this scenario: you have two master servers, called db-master1 and db-master2 and two slaves db-slave1 db-slave2. All the writes are happening on db-master1 and this will replicating to the slaves and the failover master too.

So you have your replication set up, and everything works well. But there is a point when …

"I saw the sign and it opened up my eyes, I saw the sign
Life is demanding without understanding"
–I Saw The Sign, Ace of Base

An interesting question appeared in #mysql on Freenode recently. A user was trying to build a client that would act as a replication slave so that it could consume row-based replication events coming via the replication stream, in order to transform them into JSON that could be sent to ElasticSearch. Neat idea! But he ran into a problem: it's not possible to tell whether integer values in the replication stream are signed or unsigned. Let's take a look at how that works.

read more

The Percona Live MySQL Conference 2014 in Santa Clara, California is just around the corner: April 1-4. There is a tremendous amount of activity leading up to the conference, some of which I will highlight here.

Percona Live MySQL Conference 2014 Keynote Speakers

Oracle’s Tomas Ulin will speak again this year.

I am extremely pleased with the keynote speakers we can now announce. They include speakers from major MySQL users Dropbox and Big Fish Games as well as speakers from influential technology leaders Oracle, Fusion-io, Continuent, and Percona. We are fortunate to once again have Tomas Ulin join us to talk about the future of MySQL including insight into the coming improvements in MySQL 5.7. The list of confirmed speakers and their talks are:

• …

Delayed Transaction Durability is a new SQL Server 2014 feature that was not included in SQl Server 2014 CTP1 but discreetly published in CTP2. It is a very interesting functionality that helps reducing the IO contention for transaction log writes.

In other databases engine, you will find equivalents such as:  

• Oracle: 'COMMIT WRITE BATCH WAIT|NOWAIT' (link here)
• MySQL: 'group_commit' since version 4.x (link here)
• PostgreSQL: 'group_commit' introduce in version 9.2 (link here)

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 …

The Stackforge Libra project as with most Openstack based projects is written in Python.  As anyone who has used Python before probably knows, Python has something called a GIL (Global Interpreter Lock).  The GIL basically causes Python to only execute one thread at a time, context switching between the threads.  This means you can't really use threads for performance reasons in Python.

One solution to get a little more performance is to use Eventlet.  Eventlet is a library which uses what is called "Green Threads" and hacks on top of the networking libraries to give a mutli-threaded like feel to an application.  As part of this blogging series for HP's Advanced Technology Group I'll write about some of the things I found out the hard way about Eventlet so hopefully you don't hit …

If you’re like me, you’ve probably heard of the Spider storage engine, but not used it yet.

While it has been available for some years now, I just simply haven’t used it before until now.

I suspect that has to do with ease of installation. Previously, one had to compile it with MySQL in order to use it, which excludes a lot of people. However, in MariaDB 10.0 (as of 10.0.4), it is very easy to add and use.

And with MariaDB 10.0.8 being declared RC, combined with Spider’s sheer usefulness, I only suspect its usage will become more and more widespread.

What is the Spider storage engine, and why will it be useful?

“The Spider storage engine is a storage engine with built-in sharding features. It supports partitioning and xa transactions, and allows tables of different MariaDB instances to be handled as if they were on the same instance. It refers to one possible implementation of ISO/IEC …

I checked in some improvements to Shard-Query.

Now STD, STD_SAMP, VAR and VAR_SAMP can be orders of magnitude faster for large data sets. This is because they are now distributed like COUNT, AVG and other fully distributable MySQL aggregate functions.   Prior to this change, my test query would create a 22GB (530M row) temporary table.  It now creates a one row temporary table.  This reduces network traffic, temporary storage space and increases performance.

Shard-Query better reports initialization errors. This mostly means that if you don’t have gearmand running you will no longer get a cryptic PHP output, but a nice error message.

You can change the storage engine for the repo by changing only one line in shard_query.sql. This lets you more easily install on Infobright, which needs MyISAM tables, not InnoDB tables in the repo.