The latest from the MySQL community

If you've spent more than a few years in the programming or technology business, sometimes it takes a bit of a refresher course to take you back to that warm, fuzzy feeling that comes from accomplishing your first programming "miracle". Yesterday, I happened to give that refresher course to myself while walking my twin brother, Andrew, through the first steps of setting up a MySQL database and creating a simple PHP page which displayed the contents of a table. I tell you, when I heard my brother say for the first time, "Wow, that's really cool!", it took me back about ten years to that "lightbulb-going-on" moment when I created my first Symantec Q&A database application on a 386 machine in a warehouse at United Parcel Service.

That feeling, you know, the one of "holy crap, I just made the computer do something!" It's a pretty great feeling, as I'm sure anyone reading this will attest. It's a feeling of simultaneous bewilderment …

Since OSCON, most of my time has been focused on editing a book, which is about to be finished. As I’m getting my commutes back, I have been reading up on what I’ve missed on Planet MySQL (which I affectionately call “The ‘planet.”

Y’all are prolific!

Jeremy’s On Open Source Citizenship got me thinking about the whole movement. I think there’s still a place for proprietary software in the world, as much as folks tout that “open source is ALWAYS better, because more people see it, therefore more people can help change it.”

Whenever anyone suggests a monolithic solution, I cringe. This all ties into the patent issues that are strongly debated these days. I’m still trying to figure out how I feel about everything.

Jeremy’s article talked about how Yahoo! (as an example) couldn’t just open up all the source, …

Hey, looks like someone decided to give a spin to the old MySQLCC (aka Mysql control center) , see Sourceforge project page by releasing version 0.9.7.

Last Saturday was the 25th anniversary of the IBM PC.  For those who were into computers back then, this was a huge legitimization of the microcomputer.  Until that point, there was no big vendor involved.  The Apple ][ was successful and spawned the first "killer app" with Visicalc, and there were lots of hobbyist machines running CP/M or weirdo home grown operating systems.  But it wasn't until IBM's entry into the market that things really took off.  Don Estridge, led a team from Boca Raton to develop IBM's entry into the microcomputer market with a charter to go outside and use industry standard components, rather than work within IBM's own bureaucracy.  The result was faster …

Let us recap the successful open source business models thus far:

1) Sell stuff around Open Source. O'Reilly is the obvious winner in this arena. Their books and conferences go hand in hand with the open source community.

2) Support. IBM Global Services does an amazing job at this. Do you have something built on an Open Source stack that you need supported? They support most anything. Look at HP's announcements as of late and you can see that they are quickly trying to move into this area.

3) Update Services. Ask those who buy Redhat Network what the value is in the model and they will tell you that it is in updates. There is minimal monitoring built into Redhat Network, but the real value is in the updates.

4) Dual License. Give away the software and for those who can not use the software under an open source license, sell them a commercial license. This is the …

I wrote an article a while back about how to order updates in MySQL so you don't violate a unique index. I said I'd write another article on how to swap numbers in a sequence with a unique index. This is that article, but I'm going to make it a little more generic: how to reverse a (possibly ordered) sequence.

I've been thinking about this for a while, wondering if there's a way I can do it in-place in one statement (I like to pile challenge upon difficulty). I've thought of a number of techniques, some using one statement, some using more, some that won't work on MySQL, some that will.

A couple of days ago, I was thinking about what we need to implement inside MySQL to support easier replication fail-over (of an old master to a new master).

I came up with some preliminary ideas that I scetch below. If you have any suggestions on how to solve these problems in a smarter way, please write a comment to this blog entry.

PROBLEM 1: The fail-over infinite looping problem

The scenario is that four servers A, B, C, and D (with server ids 1, 2, 3, and 4 respectively) replicate in a topology { A->B, B->C, C->D, D->A }. Server A crashes. The DBA wants slave B to connect to master D instead and continue with the circular replication.

The problem is that events generated on server A that has been replicated to B but not to C and D will replicate in the circle forever.
The normal loop detection that MySQL has discards events that are generated on the same server, but …

This week LinuxWorld Expo will convene in San Francisco.  MySQL has a booth there where we'll be showing off the latest new technology around the forthcoming MySQL 5.1 and MySQL Network.  We also have a reception Wednesday evening next to Moscone conference center at Jillian's.  It's a chance to meet MySQL developers, execs, customers, partners in a nice social context with beer, pizza and pool.  Hey, what more could you ask for?  But space is limited, so be sure to RSVP.

• LinuxWorld Expo: Overview, …

For those who have been emailing me about the engine I displayed in my blog this weekend:
http://tangent.org/index.pl?node_id=503

Directly to the source:
http://download.tangent.org/table_functions_engine-0.1.tar.gz

This engine allows you to plug C style functions into the storage engine interface with minimal hassle. This is incredibly alpha, and I have found several bugs in 5.1 release related to the loadable engine interface in the process. You must be using the very latest MySQL source tree from http://mysql.bkbits.com/ if you hope to make this work.

BTW I don't expect many people to make this work at this point. You must read the README.

The interface …

Having gotten my daughter a new laptop to take off to college where she starts as a freshman in a couple of weeks, I now have her old laptop, still quite serviceable albeit older, larger, heavier, etc. So I set about setting it up as a system where I can do BK pulls of various MySQL versions, be continuously running and testing new pulls from the 5.1 and 5.2 trees.

The first thing I did was to take the laptop, a Toshiba Satellite with a 30GB hard drive, Celeron processor and 256MB RAM, reformat it and install Slackware 10.2. This is my preferred operating system except for a couple of systems that are rather low on my priority to convert, where it's vital to keep them running as Windows because of a number of applications. I set up the following partitions:

hda1  6.6GB /
hda2  6.6GB /usr
hda3  512MB (swap)
hda4 13.3GB /usr/local

The swap partititon is my standard formula, double the size of the RAM, …