Colin Charles Agenda

Following my previous post on the launch, I just rolled Ubuntu 14.04 LTS on an Amazon EC2 t1.micro instance (not something you expect to run a database server on, for sure – 1 vCPU, 0.613GiB RAM). If you do an apt-cache search mysql you get 435 return result sets with the default configuration (trusty: main & universe).

If you do apt-get install mysql-server, you get MySQL 5.5. You enter the password of choice, and before you know it, MySQL is installed (a SELECT VERSION() will return 5.5.35-1ubuntu1).

Next you decide to install MariaDB. I run an apt-get install mariadb-server. It pulls in libjemalloc (for TokuDB) and I expect future releases to ship this engine by default. You enter the password, and you get a new message (as pictured).

I verify my test database that I created exists. It does. A SELECT VERSION() returns 5.5.36-MariaDB-1. The innodb_version returns 5.5.36-MariaDB-33.0.

I’m curious about MySQL 5.6 now. So I run apt-get install mysql-server-5.6. Not so straightforward. 

start: Job failed to start
invoke-rc.d: initscript mysql, action "start" failed.
dpkg: error processing package mysql-server-5.6 (--configure):
 subprocess installed post-installation script returned error exit status 1
Setting up mysql-common-5.6 (5.6.16-1~exp1) ...
Processing triggers for libc-bin (2.19-0ubuntu6) ...
Errors were encountered while processing:
 mysql-server-5.6
E: Sub-process /usr/bin/dpkg returned an error code (1)

Looks like MySQL 5.6 is more memory hungry… I edited /etc/mysql/my.cnf to ensure that innodb_buffer_pool_size = 64M (I increased this to 128M and it worked too) was set (there was nothing in the default config) and re-ran apt-get install mysql-server-5.6 and it started. My test database was still around ;-)

I wanted to make sure that MySQL 5.6 isn’t more memory hungry just on that instance so I created yet another clean t1.micro instance and did an apt-get install mysql-server-5.6. Same error. Reported lp#1311387.

Nothing to report in particular about Percona – 5.5.34 Percona XtraDB Cluster (GPL), Release 31.1 (Ubuntu), wsrep_25.9.rXXXX. One thing is for sure – if you’re playing around with the ecosystem, installs and upgrades aren’t exactly straightforward.

Inspired by Yngve Svendsen’s post, I too think it makes absolute sense to congratulate Ubuntu on the 14.04 LTS release (some server notes – MySQL has a section dedicated to it). Ubuntu users have a lot of server choice today (that’s from all major MySQL ecosystem vendors):

• MySQL 5.5.35 ships in main. It is the default MySQL. Oracle has committed to providing updates to 5.5 throughout the LTS release cycle of Ubuntu (which is longer than the planned EOL for 5.5). This is why the grant of a Micro Release Exception (MRE).
• MySQL 5.6.16 ships in universe. 
• MariaDB 5.5.36 ships in universe.
• Percona XtraDB Cluster 5.5.34 ships in universe. 

Ubuntu’s pitch is being the cloud platform of choice, with OpenStack support. This explains why Percona XtraDB Cluster (the only shipping Galera Cluster variant – no upstream Codership release, and no MariaDB Galera Cluster) is critical infrastructure as its used widely in OpenStack deployments. 451Research estimates that the OpenStack distributions market is worth $82 million in 2014 and $119 million in 2015.

Press release had a choice quote from Percona CEO, Peter Zaitsev:

“We are very pleased that Percona XtraDB Cluster is included in Ubuntu 14.04 LTS. Many organisations that use MySQL need high availability solutions to ensure that their applications meet the expectations of their users. Percona XtraDB Cluster is an easy to use, open source solution for MySQL clustering which addresses these high availability needs. We continue to see growth in Ubuntu usage by our customers and our open source software users so we are confident that the inclusion of Percona XtraDB Cluster in Ubuntu 14.04 will help spread the adoption of cost-effective, high availability MySQL.” Peter Zaitsev, Co-Founder and CEO at Percona

With the recent Heartbleed bug, people are clearly more interested in their MariaDB/MySQL running with SSL and if they have problems. First up, you should read the advisory notes: MariaDB, Percona Server (blog), and MySQL (blog).

Next, when you install MariaDB (or a variant) you are usually dynamically linked to the OpenSSL library that the system provides. Typically on startup of MariaDB 10.0.10 on CentOS 6.5 (packages from the MariaDB repository), you can check what your status of SSL is.

MariaDB [(none)]> show variables like 'have_ssl';
+---------------+----------+
| Variable_name | Value    |
+---------------+----------+
| have_ssl      | DISABLED |
+---------------+----------+
1 row in set (0.00 sec)

This means that SSL options are compiled, but mysqld didn’t start with it. You can verify SSL is linked dynamically:

ldd `which mysqld` | grep ssl
	libssl.so.10 => /usr/lib64/libssl.so.10 (0x00007ff82d1b1000)

If you are running with SSL enabled (some documentation at MySQL) you will have different options naturally. You can do this via: /etc/init.d/mysql start --ssl. Output now changes:

MariaDB [(none)]> show variables like 'have_ssl';
+---------------+-------+
| Variable_name | Value |
+---------------+-------+
| have_ssl      | YES   |
+---------------+-------+
1 row in set (0.00 sec)

The value NO will be displayed if the server is not compiled with SSL support. See SSL Server System Variables for more.

If you are a MySQL power user in Korea, its well worth joining the Korean MySQL Power User Group. This is a group led by senior DBAs at many Korean companies. From what I gather, there is experience there using MySQL, MariaDB, Percona Server and Galera Cluster (many on various 5.5, some on 5.6, and quite a few testing 10.0). No one is using WebScaleSQL (yet?). The discussion group is rather active, and I’ve got a profile there (I get questions translated for me).

This is just a natural evolution of the DBA Dinners that were held once every quarter. Organised by OSS Korea, and sometimes funded by SkySQL, people would eat & drink, while hearing a short message about updates in the MySQL world (usually by me, but we’ve had special guests like Werner Vogels, CTO Amazon; recently we’ve seen appearances by Monty, Patrik Sallner, Michael Carney where mostly all we do then is eat & drink).

So from meetups to getting information online, in a quick fashion. Much hunger for open source in Korea, very smart people working there on services feeding the population (where some even make it outside of the local market). The future of open source in Korea is definitely very bright.

Today I performed a brew update. I noticed that MariaDB now exists as stable (5.5.30) and devel (10.0.2). Brew formulas also exist for MySQL (5.6.10) and Percona Server (5.5.30-30.2) now. 10.0.3 is around the corner but I wanted to run 10.0.2 now. This is how I did it:

brew unlink mariadb
brew install --devel mariadb

It’s that simple!

Just yesterday, I’m sure many saw Twitter opensourcing their MySQL implementation. It is based on MySQL 5.5 and the code is on Github.

For reference, the database team at Facebook has always been actively blogging, and keeping up their code available on Launchpad. Its worth noting that the implementation there is based on MySQL 5.0.84 and 5.1.

At Twitter, most of everything persistent is stored in MySQL – interest graphs, timelines, user data and those precious tweets themselves! At Facebook, its pretty similar – all user interactions like likes, shares, status updates, requests, etc. are all stored in MySQL (ref).

The media has picked up on it too. A fairly misinformed piece on GigaOm (MySQL has problems focused on Stonebrakers fate worst than death? Pfft. Facebook wants to move its code to github? Read the reasoning — its spam handling on LP.), and a shorter piece on CNET.

Both Twitter and Facebook code trees mention that its what they use in their environments, but it’s not supported in any way, shape or form. Facebook recommends Percona Server or MariaDB. Facebook also has tools like online schema change in the repository, amongst others like prefetching tools written in Python.

I haven’t had the chance to play with the Twitter release yet, but it looks like this can only push Percona Server and MariaDB forward. Based on 5.5, some of these BSD-licensed features can make it in, and some have already made it in I’m sure. And what pushes these servers, will push MySQL forward (see lots of new features in MySQL 5.6).

On a personal note, it is amazing to see some MySQL-alumni push this forward. At Twitter, there’s Jeremy Cole and Davi Arnaut. At Facebook, the team includes Domas Mituzas, Harrison Fisk, Yoshinori Matsunobu, Lachlan Mulcahy. Nothing would be complete without mentioning Mark Callaghan (though not-MySQL alumni, active MySQL community member) who led a MySQL team at Google, and now at Facebook.