MariaDB 5.3/5.5 has introduced a new join type “Hash Joins” which is an implementation of a Classic Block-based Hash Join Algorithm. In this post we will see what the Hash Join is, how it works and for what types of queries would it be the right choice. I will show the results of executing benchmarks for different queries and explain the results so that you have a better understanding of when using the Hash Join will be best and when not. Although Hash Joins are available since MariaDB 5.3, but I will be running my benchmarks on the newer MariaDB 5.5.

Overview

Hash Join is a new algorithm introduced in MariaDB 5.3/5.5 that can be used for joining tables that have a equijoin conditions of the form tbl1.col1 = tbl2.col1, etc. As I mentioned above that what is actually implemented is the Classic Hash Join. But its known as Block Nested Loop Hash (BNLH) Join in MariaDB.
The Classic Hash Join Algorithm …

We’re quite happy that we’ve released four major releases that are production ready (better known as generally available or GA in the MySQL world) in the last 26 months. That is just a little over two years, and a whole lot of features. In that same time, MySQL has seen one GA release (MySQL 5.5) and we’re all eagerly awaiting the upcoming MySQL 5.6.

You’ll note that we built MariaDB 5.1, 5.2, and 5.3 based on the MySQL 5.1 codebase. A significant number of features went into MariaDB 5.3 (our biggest GA release to date), with the biggest changes in the optimizer in over a decade. There were also many replication based …

As I mentioned here, there is a slight change for enabling the [original] InnoDB Plugin in MariaDB 5.5 (as compared to how you would enable it in 5.1).

Remember, in MariaDB 5.5, if you do not “enable” (i.e., add anything to the config file to do so) the InnoDB Plugin in MariaDB 5.5, you’ll end up with XtraDB+ for your InnoDb plugin. However, if you do “enable” the InnoDB plugin, then you end up with the original InnoDB plugin provided by Oracle/InnoDB.

The change is that the plugin file (.dll for Windows, .so file for Linux) which was previously named “ha_innodb_plugin.dll” is now just “ha_innodb.dll”.

Thus, if you previously enabled the plugin with (would have been in a 5.1 instance):

[mysqld]
ignore_builtin_innodb
plugin-load=innodb=ha_innodb_plugin.dll;innodb_trx=ha_innodb_plugin.dll; …

One of the things we (Team MariaDB) talked quite a bit about since we released was PBXT. It was a feature differentiation to MySQL as we shipped another storage engine. It was included in MariaDB 5.1, 5.2, and 5.3; however with our release of MariaDB 5.5, PBXT (docs in the Knowledgebase) has been deprecated and not built by default any longer.

The reason behind it is clear: PBXT is currently not under active development. We still include it in the source releases and if you would like to use it, you just have …

The good news is that we have just released plenty of MariaDB & MySQL training dates covering the summer months and even into October across the globe.    This new training calendar includes all of our current training courses in plenty of locations both in North America and Europe. 

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These are things I like that I consider differences from last years conference. There are plenty of other things I like that don’t need to be listed here.

• The overall tone and feel of the conference was much less marking and much more technical
• Refreshingly honest keynotes. There was a lot of coming clean about the history of MySQL and the conference.
• Percona is very technical but it is also a business. They are very good about bringing out the technical and not being pushy about the business.
• No ice cream social. A thousand people shaking sticky hands with each other is never a good idea.
• percona.tv
• The conference was busy but never crowded

Now for the dislike:

• Only one song before every session.
• The chairs. Damn the chairs.
• Wifi failed more often than it worked. Most of the time I was tethered to my phone. …

As an experiment, I have converted the MariaDB Bazaar repository into Git.

https://github.com/atcurtis/mariadb

Should be interesting...

An increasing number of organizations run applications that depend on MySQL multi-master replication between remote sites.   I have worked on several such implementations recently.  This article summarizes the lessons from those experiences that seem most useful when deploying multi-master on existing as well as new applications.

Let's start by defining terms.  Multi-master replication means that applications update the same tables on different masters, and the changes replicate automatically between those masters.  Remote sites mean that the masters are separated by a wide area network (WAN), which implies high average network latency of 100ms or more.  WAN network latency is also characterized by a long tail, ranging from seconds due to congestion to hours or even days if a ship runs over the wrong undersea cable.
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Being a data recovery specialist and having recovered countless GBs of corrupted, and/or stranded, InnoDB data in my days, I am very happy to hear about the new InnoDB Transportable Tablespaces coming in MySQL 5.6!

Back in the day, if you had a stranded .ibd file (the individual InnoDB data file with –innodb-file-per-table option), you basically had nothing (even though that file contained all of the data). This was because unless you had the original instance that that particular .ibd file (table) originated from, there was no way to load it, import, or dump from it. So it was not of much use, though all the data was *right* there.

Thus I created the method of Recovering an InnoDB table from only an .ibd file (I should note that this was before the …

LinkedIn has what they call "inDays" where employees may so something interesting which may not be directly related to their day job. I spent my inDay by porting my old WL820 project (External Language Stored Procedures) to MariaDB 5.3.

The code, as usual, is available on LaunchPad ... To get the branch, simply do:

bzr branch lp:~atcurtis/maria/5.3-wl820 The test cases pass... I haven't tested