Not sure if the post title actually reflects the contents. 

This post describes how you can obtain the traces that MySQL server leaves behind for you if you ask it to. Once you have the traces, you can use it for:

• Debugging - It can help you to find out which source file is the server crashing, for eg.
• Learn- learn more about which functions/methods are called for a particular query by the client

Okay, so lets start.

Traceable Server

To be able to obtain traces, your server needs to be compiled with "debug" enabled. If the version information shows you something like this:

Ver 5.1.24-rc-debug for pc-linux-gnu on i686 (Source distribution)

with 'debug' appended to the version name, then you have a traceable server, else you will have to recompile it by enabling debug support:

./configure …

Few days back, one of my colleagues posted a good question. It sounds something like this;

"Temporary tables are session based that means under different sessions we can create temporary tables with similar names. Now since slave thread is singleton, how does it manage to keep them separate?"

He was very much right in asking this and the answer is not all that intuitive. Lets go through the binlog events to see why it is not that intuitive.

   1: mysql> SHOW BINLOG EVENTS IN 'log-bin.000016';

   2: . . .     

3: | log-bin.000016 |  389 | Query       | 2515922453 |         488 | use `test`; CREATE TEMPORARY TABLE test.t(a int)         |    

4: | log-bin.000016 |  488 | Query       | 2515922453 |         582 | use `test`; INSERT INTO test.t(a) VALUES(1)         |    

5: | log-bin.000016 |  582 | Query       | 2515922453 |         676 | use `test`; INSERT INTO test.t(a) VALUES(3) …

I work on the MySQL Enterprise Tools team, formerly of MySQL and now with Sun Microsystems. The 2.0 version of the Enterprise Monitor is well under way. As part of this, the Java server backend has been refactored to utilize Spring and Hibernate. Honestly, I didn't know either one of those technologies before starting this project. Oh, what a fun road it has been...

A big draw for using an off-the-shelf ORM was so that we didn't have to write our own (kind of bad and slightly wrong -- those darn transactions) caching implementations for the custom one-off ORM that existed previously. A lot of our internal meta-model is very static, so …

In MySQL, it's possible to comment out portions of code that you only want to work in specific MySQL versions:

i.e.
CREATE DATABASE /*!32312 IF NOT EXISTS*/ `a` /*!40100 DEFAULT CHARACTER SET latin1 */;

The problem with this, is that the decimal point is omitted - and there's a real assumption that with something like 3.23.12 the "12" portion never exceeds 99.

When I look at 5.0, MySQL is currently at 5.0.60 - and there are still minor changes happening. 5.1 is at 5.1.25, and not even GA. Assuming that 5.1 does the same community/enterprise split and shuffles through releases in even numbers, how long will it take before we have 5.1.100?

If we do get there, the SQL commenting feature will need upgrading.

In MySQL, it's possible to comment out portions of code that you only want to work in specific MySQL versions:

i.e.
CREATE DATABASE /*!32312 IF NOT EXISTS*/ `a` /*!40100 DEFAULT CHARACTER SET latin1 */;

The problem with this, is that the decimal point is omitted - and there's a real assumption that with something like 3.23.12 the "12" portion never exceeds 99.

When I look at 5.0, MySQL is currently at 5.0.60 - and there are still minor changes happening. 5.1 is at 5.1.25, and not even GA. Assuming that 5.1 does the same community/enterprise split and shuffles through releases in even numbers, how long will it take before we have 5.1.100?

If we do get there, the SQL commenting feature will need upgrading.

Sun Microsystems, Inc. today announced the general availability of MySQL™ Cluster Carrier Grade Edition 6.3, the latest version of its high-availability open source database, especially designed and certified for use in carrier grade telecom environments, such as Subscriber Data Management systems (HLR, HSS) and in Service Delivery Platforms. This new release enables Service Providers and Network Equipment Providers to deploy larger database applications and provide data availability across geographies in case of site-level failure. Additional MySQL Cluster 6.3 information and downloads are available now at www.mysql.com/cluster.

OmniMySQL 0.0.4 is a minor release fixing two bugs that I should have caught (it now crashes less). The current release can be downloaded here.

Since meeting yesterday with Vladimir Voskresensky, a Sun colleague from St Petersburg, I have a new favourite answer to the request “so tell me an example of technical advantages resulting from Sun’s acquisition of MySQL“:

Using NetBeans as an IDE (Integrated Development Environment) for coding and learning MySQL.

Now, that’s a simple answer, and that’s because it’s a simple and beautiful thought. But let’s start from the beginning.

In my days as a coder, I enjoyed the command line. I’ve used various coding editors, and I’ve disliked the hassle of learning new IDEs, who sometimes are more of a straightjacket than a productivity enabler. So call me conservative if you will, but …

When a PR contact from Reddit contacted us about "exciting news", a mixture of workload and getting sent press releases not remotely related to open source led me to ignore the request to meet with Reddit. My bad. The news is that Reddit has decided to open source the code behind reddit.com. The Reddit blog states: "There are only five of us who work on reddit; we couldn't have made this site if it weren't for a great community of developers. In no particular order, here's a quick list of the open source products that reddit is built and runs... READ MORE

If you happen to be in Munich, Germany next week, don't miss out the final Sun/MySQL launch event which will take place on Thursday, 26th of June at the "Sofitel Munich Bayerpost", Bayerstraße 12, D-80335 München.

Simon Phipps will speak about "Sun and Open Source - How it has changed the industry", Kaj Arnö will give a talk about the positioning, strategy and momentum of MySQL as a part of Sun. Other speakers include Donatus Schmidt (Marketing Director Sun Germany) and Ralf Gebhardt (Sales Engineer, MySQL). You can see the entire agenda here, you need to …