Many moons ago I pushed in an example "daemon plugin" to the server. This week I have Calvin Sun, our team lead for Storage Engines, visiting me. I've been going over the plugin architecture and other internal pieces of the server with him. I'll be posting more about our joint work in a later post.

While going over the plugin structure with Calvin I noticed that the daemon plugin example doesn't give much of an example of what you can do. So I hacked a little more on it :)

You can find it here:
http://download.tangent.org/daemon_example-0.1.tgz

What it now demonstrates is how to create a "heart beat" file. Daemon plugins are raw plugins inside of MySQL, you can literally do anything with them. For hacking the server they are an excellent way of making use of your full imagination.

The Example creates a …

MySQL has no built-in functionality to calculate a table’s checksum in any storage engine but MyISAM (this is not true; I read the manual wrong, but it doesn’t eliminate the usefulness of the technique in this article). Table checksums can confirm that two tables are identical – useful to verify a replica server is in sync with its master (see my article on reliable MySQL replication for more). Fortunately, it’s easy to calculate a checksum on non-MyISAM tables with user variables.

Sorry for the short outage, due to a small coding glitch the script that updates the planet feeds got stuck and it took us a bit to find the problem... But thanks to Jay we now spotted the bug and it was fixed quickly!

Hi Folks,

This is an announcement for a webinar in German. Therefore only written in German. If you are interested in the security topic be sure to see the english webinar, which is stored here.

Web-2.0-Anwendungen absichern

Die verbesserte Einsatztauglichkeit der Web-2.0-Anwendungen wird auf Kosten von neuen Sicherheitsproblemen erworben. Sowohl die mächtige Logik im JavaScript als auch der permanente Login auf vielen Sites bergen Risiken, die anders und gezielt beantwortet werden müssen. Dieses Webseminar gibt einen Überblick, bewertet die Probleme und stellt Lösungswege vor.

Wenn Sie Web 2.0- und AJAX-Anwendungen entwickeln, ist dieser Vortrag genau das Richtige für Sie! Hier erfahren …

I was reading this morning, and came across a passage that really struck me: we are free to act, not to be acted upon. This jibes perfectly with what I've been reading in William James. Freedom is in action, not in waiting for others to act upon us.

In the open source world, many companies treat open source as a ball-and-chain to be endured (for the marketing benefits of saying they're "open source"), rather than as a tool that gives them essential liberties and advantages. Open source is a tool, even a weapon, for MySQL, Red Hat, and others. It's a cross to be borne by others. This is reflected in their licensing: open source, but not too much.

(Incidentally, this same phenomenon shows up in all aspects of software. …

Is 15815 fixed for 4.1.23 community edition?


Paul DuBois may have indicated that in the bug report. Getting details soon.

Update: Got the official word that the patch will be provided to the community, but you will need to build and test mysql yourself.

Congratulations to Warren Young and the other developers that maintain the MySQL++ C++ wrapper around the MySQL Client libraries: version 2.2.0 has just been announced and boasts a wide range of changes. Here's a description of MySQL++ from the project web site:
MySQL++ is a C++ wrapper for MySQL's C API. It is built around STL principles, to make dealing with the database as easy as dealing with an STL container. MySQL++ relieves the programmer of dealing with cumbersome C data structures, generation of repetitive SQL statements, and manual creation of C++ data structures to mirror the database schema

I will be at the big anual MySQL conference end of April. This means I will meet with a lot of coworkers, students and customers, friends and many new faces. Lots of new stuff to learn. But I will also work over there.

First of all, we will deliver lots of certification exams, MySQL 5.0 for administrators and MySQL Cluster. Sarah and will give each a 3 hour session to prepare candidates for the DBA exam. We will also be around to answer any questions on certification in general.

Then, I will also give two 45 minutes talks. One will summarize my students' wishlist for MySQL features, the other will be about the Blackhole Storage Engine.

As many of you know 4.1 does not have the thread bug fix as mentioned in this post. So, throwing a new mySQL server into production can cause a spike of threads that exposes this bug. Why? Well, for the most part INNODB has not filled its buffer pool for the most part.


For example, assume you have a box with 16 GB of ram, running 64-bit Linux. Let's look at MySQL when it first starts.

Here is some sample output from top

top - 18:46:22 up 400 days, 22:30,  3 users,  load average: 0.65, 1.08, 0.73
Tasks: 132 total,   2 running, 130 sleeping,   0 stopped,   0 zombie
Cpu(s):  0.7% us,  0.5% sy,  0.0% ni, 92.2% id,  6.5% wa,  0.0% hi,  0.2% si
Mem:  16253552k total,  3406008k used, 12847544k free,    79364k buffers
Swap:  8388600k total,      160k used,  8388440k free, …