I'm preparing to do some simple MongoDB hackathons in Scandinavia, and because I don't want to forget how to do all the steps, I actually wrote down an example exercise.

This is a simple and fun exercise just to get some data into MongoDB and then get it out again. We're going to use some awesome JavaScript tools for the out part: Node.js and Crest for a simple HTTP API, and Angular.js to draw the pretty pictures. So this is not just a MongoDB hackathon but more like a fullstack JavaScript or MEAN hackathon. (Strictly speaking there's no Express.js, so maybe this is a NMCA hackathon?)

Install MongoDB

The usual apt, yum and brew methods will work for this tutorial.

Last week I was assigned to work on a simple yet interesting problem. MongoDB stores data as JSON. But it turns out we often have customers - especially in the important financial services market segment - where data is in XML. (Yes, SOAP still exists too!) To store that data into MongoDB, we need to transform it into JSON.

(For the impatient reader: here's the Github link!)

Storing XML as a text field

There are various ways one could do this. For example one could simply store the XML document as a whole in a single field, and then extract just a few parts of the XML that are stored as individual JSON keys. One reason to do this is that they can then be indexed and used in queries.

For example:

Flavio of MongoDB fame complained in a tweet about wanting a date format in JSON. Currently you can only express strings and numbers as the primitive data types in JSON, as well the composite forms of a list: [] and an object: {}. The latter is essentially just a subhierarchy in the object/array that is your full JSON document.

i wonder why there's no "STANDARD" way to (de)serialize times / date times into / from json! They might not be "primitive" but COME ON!!

In the series of shell one liners, today I wanted to stalk someone, so I came up with this one liner to show all diffs ever created by a specific user in a give bzr repository:

bzr log -n0 | grep -B 1 henrik | grep revno | grep -v merge | \
awk -F'revno: ' '{print $2}' | while read revno; do echo; \
echo '#####################################################################'; \
echo revno: $revno; bzr diff -c$revno; done 

bzr log -n0 prints out the full log history of your repo. It may look something like this:

    ------------------------------------------------------------
    revno: 2441.2.16 [merge]
    committer: Henrik Ingo 
    branch nick: drizzle-json_server-keyvalue

In my previous post I explained why I believe the production of RPM and DEB packages should be more integrated with the rest of your development process. Now it's time to look into how you can put the RPM build scripts inside your main source code repository, and in particular how I did that to produce RPM packages for Drizzle.

There has been an increase in the discussion about MySQL replication and how to make it happen faster. I don't think Marco Tusa's blog is on Planet MySQL, so let's highlight it first: A dream on MySQL parallel replication. This is a good account of what it looks like out in the field of MySQL databases today - you are increasingly aware of replication, fearing it will be a bottleneck you cannot fix.

As some Facebook friends already guessed from my status updates this week, my 9 month paternity leave is now over and I've survived my first week back in work life, waking up at seven in the morning! This is just a personal-life blog post to let everyone know what I'm up to, (For those asking: Ebba is doing fine, she recently started to stand up and even takes steps if I hold her hands.)

During the past months I had many interesting conversations and ideas of what to do next, but in the end Nokia was the company standing out with a very interesting offer. So as of last Tuesday I work at Nokia as Senior Performance Architect in the Mobile Solutions division, better known as the Nokia Ovi web services.

This is the final part in a series of posts about the MepSQL build system known as MepSQL Bakery. MepSQL is a (yet another) fork of the MySQL database server, with the server based on the MySQLatFacebook code and the build system based on the MariaDB build system.

In this final post I wish to draw a high level picture of the complete process of building TAR, DEB and (eventually) RPM packages from the source code. There's not much more technical details to add to the previous posts, instead I'm going to make some, shall we say "archeological", observations which imho are interesting given how the build system has evolved when being passed from one project to another. Perhaps more importantly, I will also say a few words about where I think the future direction lies.

Yesterday I wrote down the approach used in the MepSQL build system to parameterize the TAR package name produced. Today I will follow up with how the same was done for building DEBs. The motivation is to create a system that can be used flexibly to create packages of any MySQL fork, with any brand name: mepsql-server-*.deb, percona-server-server-*.deb, mariadb-server-*.deb or even just mysql-server-*.deb (which I might do some day).

While yesterday's tricks with the TAR files were rather straightforward, with the process of building DEBs this turns out to be much more challenging. But not to worry, like my former collague Bernhard Ocklin used to say: This is software, anything is of course possible.