Data warehouse administrators often want to give different users access to different subsets of the data. The OLAP model is a powerful paradigm for exploring data, and this paradigm also allows complex access-control rules to be expressed easily.

Mondrian already implements a rich set of access-control primitives (see mondrian schema guide), but we are considering some features to make mondrian more expressive in future releases.

Introduction: Access control in mondrian-2.4

In the current version of mondrian, roles are defined by elements in the mondrian schema file. A role can have access granted, or denied, for cubes, hierarchies, and members of hierarchies.

The type of access granted to an object is inherited by its children. For example, if you deny access to a schema, then access to cubes in …

Earlier this month (on the 4th, to be exact), OmniTI celebrated its 10th birthday. From humble beginnings in Theo's basement to a company of almost 50 employees, things have certainly changed. We now have an entire division devoted to email (Message Systems), a new office opening in New York, and a strong reputation that we all cherish. I haven't been here since the beginning, but I'm very proud to be a part of this team.

On his blog, Theo shares his thoughts on the occasion:

OmniTI is my other child, and the stresses and accommodations that I and everyone close to me have shouldered for …

The sixth annual MySQL Conference & Expo, co-presented by MySQL AB and O'Reilly Media, will take place April 14-17, 2008 in Santa Clara, California. The event is expected to bring over 1,500 open source and database users together to harness the power of MySQL and celebrate the large and active MySQL ecosystem. The call for participation is now open for prospective speakers -- submissions will be accepted until October 30, 2007.

To submit a proposal or learn more about the conference, please visit www.mysqlconf.com.

This year, it seesm that whenever I go out for significant travel, the following things will break on my trip:

• a laptop power supply
• a disk

At least this time the disk is part of a RAID1 array.

Oh, and for some reason my mythbackend stopped doing anything a few days ago…. and I wasn’t checking it. grr… annoying. At least there’s not much on TV.

There was long played scalability issue with InnoDB auto-increment field. For details check Bug 16979. In short words the problem is in case of insert into table with auto-increment column the special AUTO_INC table level lock is obtained, instead of usual row-level locks. With many concurrent inserted threads this causes serious scalability problems, and in our consulting practice we had a lot of customers who was affected by InnoDB auto-inc. For several of them we even advised to replace auto-inc column by that or another solution.
Good news is the bug is fixed. Bad news is it is fixed only 5.1.22, which is not released yet.
I wonder if the fix is going to be ported to 5.0, as I mentioned it affected many production systems and not all of them are ready to upgrade to 5.1.
…

So, I'm developing a new application that's in the capacity planning phase. The application is designed to scale linearly and scale is very easy to do just by adding another database server. But, at what point do you upgrade? What point in the applications life do you add new servers to serve the expectation of the users?

To figure out these questions, thresholds need to be defined. When these thresholds are exceeded then upgrades need to occur.

Here is a process (my process) of questions to ask to define thresholds: First I start out with generic questions listed below.

What is the expected amount of users who are going to use the product initially?

What is the expected usage pattern? For instance if they are adding data what is the add rate? If they are reading data what is the read rate?

Given that the first two questions are answered now ask when is it going to …

As noted already in March and described more closely in July, we had a MySQL Developer Meeting in Heidelberg, opened up for selected members of the MySQL community. Since yesterday, I’m back and reflecting upon how it all went.

The first reflection is that I’m biased, since I was organising the meeting together with above all Patrik Backman (for the agenda) and Georg Richter (for the lion’s share of all real work, such as the coordination with our venue, Marriott Hotel). But I would still like to concur with the many MySQLers who think it was “the best MySQL Developers Meeting ever“.

So what made the meeting a success?

We got plenty of work done. Our motto was “Working Together“, making use …

Hot on the heels of the MySQL Japan User?s Conference, the Japanese-language versions of the Developer and DBA certification exams were published on Sep. 25.

This means that the following exams are now available in Japanese:

• 003-002 : Certified MySQL 5.0 Developer Part I
• 004-002 : Certified MySQL 5.0 Developer Part II
• 005-002 : Certified MySQL 5.0 DBA Part I
• 006-002 : Certified MySQL 5.0 DBA Part II

As always, the exams are available through Pearson VUE, and all 121 Japanese testing centers are standing by to help you with the exams.

For more information on the Japanese certification exams, see http://www-jp.mysql.com/certification/

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