Taking a little break from refactoring temporal data handling this evening, I decided to run some profiles against both Drizzle and MySQL 5.1.33. I profiled the two servers with callgrind (a valgrind tool/skin) while running the drizzleslap/mysqlslap test case. In both cases, I had to make a small change to the drizzled/tests/test-run.pl Perl script.

For the MySQL build, I used the BUILD/compile-amd64-debug-max build script. For Drizzle, I used my standard build process which builds Drizzle with maximum debugging symbols and hooks. It's worth noting that the debug and build process for MySQL and Drizzle are very different, and the MySQL debug build contains hooks to the DBUG library, which you'll notice appear on the MySQL call graphs and consume a lot of the overall function calls. You won't see this in the Drizzle graphs because we do not use DBUG. For all intents and purposes, just ignore the calls to anything in the DBUG library …

loops is a small and lightweight framework for Ruby on Rails and Merb created to support simple background loops in your application which are usually used to do some background data processing on your servers (queue workers, batch tasks processors, etc).

Originally loops plugin was created to make our (Scribd.com) own loops code more organized. We used to have tens of different modules with methods that were called with script/runner and then used with nohup and other not so convenient backgrounding techniques. When you have such a number of loops/workers to run in background it becomes a nightmare to manage them on a regular basis (restarts, code upgrades, status/health checking, etc).

After a short time of writing our loops in more …

I just finished up a new release of SabreDAV. The mailing list is getting some traction, and it's shows! There were quite a bit of suggestions and patches recently, so the changelog is relatively big. The best thing that can happen is of course people liking and using it, and it makes me also more excited to work on it :).

Download it here.

Most notable changes:

• Added: We're now using streams for passing contents of files around everywhere. Not only is this a big speed improvement, but it also reduces memory consumption quite a bit for larger files. It should be noted that this breaks API compatibility as the ->put and ->createFile methods will now no longer receive strings.
• Added: …

As you may know, MySQL has a dual-licensing model. You can get the source under the GPL version 2, or you can buy a commercial license.

I’ve recently been hearing a lot of confusion about when you have to buy a commercial license. People I’ve spoken to wrongly believe that they’re required to purchase a license if they’re going to use MySQL in anything but a not-for-profit business, for example. I don’t know how these notions get started, but they do.

So when are you required to buy a commercial license? It’s very simple: when you want to do something with MySQL that the GPL doesn’t permit.

Problem

A problem we occasionally see is Relay Log corruption, which is most frequently caused by network errors. At this point in time, the replication IO thread does not perform checksumming on incoming data (currently scheduled for MySQL 6.x). In the mean time, we have a relatively easy workaround: encrypt the replication connection. Because of the nature of encrypted connections, they have to checksum each packet.

Solution 1: Replication over SSH Tunnel

This is the easiest to setup. You simply need to do the following on the Slave:

shell> ssh -f user@master.server -L 4306:master.server:3306 -N

This sets up the tunnel. slave.server:4306 is now a tunnelled link to master.server:3306. So now, you just need to alter the Slave to go through the tunnel:

mysql> STOP SLAVE;
mysql> CHANGE MASTER TO …

Last week, my good colleague Gerv gently took me to task about requiring that videos submitted to the Mozilla Net Effects video program be licensed under the Creative Common NonCommercial-ShareAlike license (instead of an actual Free Culture licensed like Creative Common ShareAlike license or Creative Common Attribution license) . I thought about this for a while and got to wondering why I’d ever let fear of misuse overcome my experience and common sense.

Licensing and contract choices are often driven by fear and greed. We work, play, love and give in an …

Last week, I wrote about how the European Commission's Tool East project leveraged opentaps Open Source ERP + CRM to create an open source ERP system for the Eastern European tool and die making industry. I thought this was a very interesting example of how open source software could be used to advance social and economic development.

I was pleasantly surprised to hear encouraging feedback from many people about this project. In a time where our environment and our economies are facing unprecedented challenges, it's gratifying to know that our work could help our societies meet those challenges. I hope that the open source communities could come together and solve greater social problems in the future.

It's now more than a week since I left Sun and I have been very busy with old commitments; I had one talk at the Tampere University about "Open source licensing and how this affects quality" and a keynote about "Open Source Licensing" for the "2nd Symposium of the HyperTransport Center of Excellence" in Mannheim, Germany.

My web site, askmonty.org, is coming around nicely but it will take a couple of more weeks to add some missing information to it. After that I will start working on the Maria, MariaDB and MySQL code bases for real.

The most exiting thing that has happened so far, is that my investment company "Open Ocean" have just closed a funding round with …

I harped on this earlier this month. The network is an often over looked, but vital component of every application. I have been in many shops content with running 100Mb/s between the application and database simply because they are no where near maxing out the available network bandwidth between the two servers. What they are forgetting is there is a big latency difference between 10Mb,100Mb, & 1000mb. Speaking from my testing on Waffle Grid we see that under load 100mb connection routinely has network latency in the 3000-4000 microsecond range, while running under load in 1gbe tests we routinely run at around 1100 microseconds. By the way the same test using a Dolphin interconnect card finishes with an average latency of less then 300 microseconds. These tests average less then 5Mb/s being pushed over the network, which from a network perspective would not even hit half the available …

This Thursday (February 19th, 14:00 UTC), MC Brown & Trond Norbye will give a MySQL University session on Developing MySQL on Solaris. MC works on the MySQL Documentation Team and has been involved with quite a few Solaris things, for example porting MySQL to openSolaris. Trond has been involved with many things, including openSolaris, as you can see from his blog.

For MySQL University sessions, point your browser to this page. You need a browser with a working Flash plugin. You may register for a Dimdim account, but you don't have to. (Dimdim is the conferencing system we're using for MySQL University sessions. It …