Only a few weeks after Walter’s session on Multi-Master Replication with MMM and thanks to the great gang at MySQL Docs (my colleagues from long ago!) I’ll be doing a MySQL University session in a few days, about the GRAPH computation engine. From talks/demos I’ve done about it so far, I’ve learnt that people love it but there are lots of interesting questions. After all, it’s a pretty new and in a way exotic thing.

MySQL University uses DimDim, an online presentation service. You’ll see slides, and hear my voice. You can also type questions in a live chat room. We actually even got desktop sharing working so a live demo is possible, we’ll see how that goes on the day (I’ll make sure to have static slides for the same also

For session details and the exact link to DimDim, see the …

I'm extremely happy to announce that the MariaDB project has integrated FederatedX into the main tree and has replaced the old, un-maintained Federated storage engine! This means that from now on, I will target any FederatedX changes and enhancements for MariaDB since it will be easier than having to try to make it run as a pluggable storage engine. This also means I will have another reason why I should keep this project moving forward. I will still provide the ability for anyone who wants to use it as a pluggable engine (not that difficult) so this can be loaded with MySQL as well.

Also changed: I changed to using the BSD license for FederatedX.

For Drizzle, I will need to rewrite a good part of the code base to use libdrizzle as well as the new storage engine interface, so they will be somewhat separate projects -- though I'll do my best to keep them the same single project.

I want to thank Monty …

See the OurDelta blog for details of this release. RHEL/CentOS packages also coming.

You can now apt-get your way to MariaDB 5.1, courtesy of OurDelta and in close cooperation with Monty Program Ab. To get started, simple follow the info on the Debian and Ubuntu pages.

Quick overview

• For MariaDB we use different repository directories to ensure that you can’t accidentally upgrade or revert major versions without you explicitly choosing to do so.
• At this point we have Ubuntu Hardy, Intrepid, Jaunty and Karmic for you, as well as Debian 4 (Lenny). Etch (Debian 4) is waiting on a small fix (thanks to Antony Curtis for helping with that).
• The package names start with mariadb*, except …

Many configs have thread_stack_size configured explicitly, but that can cause rather bad trouble:

• if the stack inside a thread it’s too small, you can get segfault crashes (stack overflow, essentially). Particularly on 64-bit.
• if the stack is too large, your system cannot handle as many connections since it all eats RAM.

Let mysqld sort it out, on startup it does a calculation based on the CPU architecture, and that’s actually the most sensible. So for almost all setups, remove any thread_stack_size=… line you might have in my.cnf.

The MySQL 5.0 and MySQL/MariaDB 5.1 source code is now also available through Launchpad. If you were waiting for a version for 5.1 and are ok with building the plugin from source, now you can!

The repo contains a subdir for examples, we’re hoping many people will contribute little snippets and scripts to import and use interesting datasets. To give you a hint, with graph capabilities you are able to deal with RDF data sources. You just need to transform the XML to say CSV, import into a suitable structure, and copy the edge information across to an OQGRAPH table.

Roland Bouman’s tree-of-life (which uses xslt stylesheets) are a good example of that approach, and was the first entry in the examples tree, including an SQL dump of the base dataset (it was CC-NC licensed) so you don’t …

Testing and automation. These two are key to ensuring high quality of software releases.

Ever since I worked briefly in the team at MySQL AB that is responsible for creating the binary (and source) packages of MySQL releases, I have had the vision of a fully automated release procedure. Whenever someone pushes a new commit to the release branch revision control tree, the continuous integration test framework should kick in and do all the steps needed for producing release packages:

• Checkout the new revision.
• Build a source tarball, and save it.
• For each platform, build a binary package from the source tarball. The build should be done in a freshly installed machine without any revision control checkouts, previous build trees, or extra installed software, to ensure that no unwanted dependencies or stray …

The GRAPH engine allows you to deal with hierarchies and graphs in a purely relational way. So, we can find all children of an item, path from an item to a root node, shortest path between two items, and so on, each with a simple basic query structure using standard SQL grammar.

The engine is implemented as a MySQL/MariaDB 5.1 plugin (we’re working on a 5.0 backport for some clients) and thus runs with an unmodified server.

Demo time! I’ll simplify/strip a little bit here for space reasons, but what’s here is plain cut/paste from a running server, no edits

-- insert a few entries with connections (and multiple paths)
insert into foo (origid, destid) values (1,2), (2,3), (2,4), (4,5), (3,6), (5,6);
-- a regular table to join on to
insert into people values (1,"pearce"),(2,"hunnicut"),(3,"potter"), …

When I was younger and had lots of free time, I used to do video editing as a hobby. At that time I developed a rule that is true for many projects in general (it was also true for writing a book some years later). The rule is: When you think you are 90% done, you are only 50% done. With video-editing, this meant that when the video was more or less ready, you are still 50% away from the final goal of actually having a master copy on tape. The latter 50% would be spent on checking ending credits, watching through the video a couple of times, and in those time, rendering even simplest of effects. Using a Windows PC for video editing was in those times a shaky effort in itself, so even when mastering you had to sit there and watch through the whole tape to make sure there were no glitches.

Producing a MariaDB release has been a similar process. In our company meeting in August we were discussing "final steps" to produce a final Beta, …

We’ve been able to do MySQL 5.1 binary tarballs for a bit now (great working together with Kristian Nielsen of Monty Program), but packages are bit more tricky. Peter has been working on Debian/Ubuntu while I’ve focused on RH/CentOS. The following is from an OurDelta (trial build run) RPM install on CentOS 5 x64:

$ mysql -u root
Welcome to the MySQL monitor.  Commands end with ; or \g.
Your MySQL connection id is 1
Server version: 5.1.38-maria-beta1-ourdelta (OurDelta - http://ourdelta.org/)

mysql> CREATE TABLE test.t1 (i int) ENGINE=PBXT;
Query OK, 0 rows affected (0.10 sec)

mysql> SHOW CREATE TABLE test.t1\G
*************************** 1. row ***************************
Table: test.t1
Create Table: CREATE TABLE `test.t1` (
`i` int(11) DEFAULT NULL
) ENGINE=PBXT DEFAULT CHARSET=latin1
1 row in set (0.00 sec)

mysql> INSERT INTO test.t1 values (1);
Query OK, 1 row affected (0.03 sec)

mysql> SELECT * FROM test.t1;
+------+
| i    |
+------+
| …