Welcome to new versions of XAMPP. In the last two weeks many people tested the beta versions of XAMPP and we are now proud to release new final versions of XAMPP for Windows, Mac OS X, and Linux. All three versions of XAMPP now contain updated versions of: MySQL (4.1.13), PHP (4.4.0), phpMyAdmin (2.6.3-pl1), OpenSSL (0.9.8), and Perl (5.8.7).

To find out more or get the downloads please visit the XAMPP project page

Admitedly I am not yet MySQL certified. So my last post was more based on knowledge of DBMS in general. A few people have noted that the issues described in my previous post might not apply to the InnoDB table handler. So I will need to research this a bit. Actually I am planning to become MySQL certified and so its quite handy that the new certification guide is to be released on august 19th.

Aside from that I wanted to mention a few other tid bits that Arjen reminded my about. Number one there is the UUID() function in mysql that seems like another great way to generate unique non sequential identifiers.

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http://www.mysql.com/company/jobs/product_engineer.html

You reckon you're up for this job? Go for it!

From the ad:
Product engineering (configuration management) at MySQL is about building and packaging our products, and regression testing, on a large variety of platforms. As a product engineer at MySQL you will also find yourself being in the center of all activities, with daily contacts with all parts of the company, like support, QA, development and marketing.

MySQL now needs to hire another product engineer, to make sure we can deliver the needed products in time and with quality.

We are searching for the best, most qualified and dedicated people around. You may work from anywhere in the world as long as you have the necessary skills and technical facilities to communicate across the …

if you love fiddling around with various strange unix flavors (and microsoft windows) and slowly trying to obsolete yourself with perl scripts, product engineer for mysql ab might be the job for you.

I've been extremely busy this week so the blog hasn't been updated in a few days. If you are following the blog we would love to hear from you.

I'll update the blog over the weekend with 2 new articles.

The other day a discussion in #mysql on freenode developed concering possible issues arising from using auto increment on primary key fields due to the danger of hotspots. Since I am currently preparing a new talk first to be held at php|works on SQL performance tuning I thought that the topic would make for a perfect warming up post on the general topic.

Defining hotspots

I guess before diving into an actual discussion of the topic we first need to define what a hotspot in RDBMS lingo is. "SQL Performance Tuning" defines it as follows:
"A page in either the index or data file that every job wants to access at the same time".

Now this sentence tells us that hotspots are concerned with concurrency issues. So this indicates to us that the entire topic is probably not much of an issue when we have few users accessing the database at the same time. As a matter of …

here?s how i spent ninety minutes of work today: having been asked to look at a timing related bug, i came to the conclusion that writing a good test case really required i implement an an old feature request for a sleep() function. ninety minutes later, the code is written, approved by brian aker, and pushed to the main 5.0 tree.

and it?s the first function i?ve ever added to mysql. oh yeah, and i ate dinner while i was waiting for brian to review my patch.

i?ve also got the test case written for the other bug. but there?s some question as to what the standards-defined behavior really is ? from my reading of the sql:2003 spec, it?s implementation-defined. apparently our standards gurus (now on vacation) left other impressions.
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Did you know that... MySQL 5.0 is able to use multiple indexes for a single table?
The simplest example of where this comes in useful is ... WHERE a=10 OR b=20

This join type optimization is new in MySQL 5.0, and represents a significant change in behavior with regard to indexes, because the old rule was that the server is only ever able to use at most one index for each referenced table.

The new optimization can use intersection, union or sort-union algorithms. It's all in the manual, see http://dev.mysql.com/doc/mysql/en/index-merge-optimization.html

This series began at Part the First. If you have not read this yet, please do so now.

My partner, Ulf just found this document that is distributed with MaxDB. It is licensed under the GPL:

http://colliertech.org/~cjcollier/MySQL/MaxDB/SynchronizationManager.pdf

More perusing found this one, licensed the same way:
http://colliertech.org/~cjcollier/MySQL/MaxDB/RunningTheMessageServer.pdf

And a bit more looking found this. Also GPL.
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http://www.theserverside.net/news/thread.tss?thread_id=35745

Don't get me wrong, I love Monad.  I think it will bring a very powerful shell and scripting setup to Windows which has badly needed one for so long.  However, based on the performance I've seen out of Monad on Windows Server 2003 x64, I suspect  Microsoft decided that requiring an extra gigahertz of CPU power to run their *shell* was just out of line. 

Btw, why hasn't someone in the development community written a monad type system before now?