In the last article the performance impact of joins was shown.  This one will demonstrate cases where denormalized joins are a bit faster, as will the third article with larger data volumes.  The fourth article, the most interesting one, will show where a denormalized data model can be 50 times faster than a normalized data model. 

Here are the tables that will be involved in the sql.  The normalized ProductSmall table has a 100 million rows and is about 0.67 gig. 

create table ProductSmall (

    productSmallId int(11) not null,

    productSmallName varchar(32) not null,

    productGroupId int(11) not null,

    primary key (productSmallId),

    key idx_ProductSmall_productGroup (productGroupId),

    constraint con_ProductSmall_productGroup

My thinking was that the topic is already dead, but people have strange ideas off and on again. Have a look at the S9Y boards where you'll find someone who wants to have a storage backend "LDAP" for S9Y. This is sick and wrong! Let me explain why.


Continue reading "LDAP is not relational"

I am now an employee of MySQL. I guess my transition from Oracle to MySQL is complete.

I am super-excited to have signed on as a support engineer for MySQL! As you can read in my earlier posts, I had great experiences with MySQL support, so I’m really glad (and honored) to join the team.

Now I need to decide what direction I want to take this blog in. Maybe start a new blog with a different focus – I haven’t decided yet. Meanwhile, I have a lot of learning to do and have to get up-to-speed on things so I can be sure to do the support team proud! It’s going to be a little different from being a DBA, that’s for sure…

Anyway, I have a lot of ideas for future blog entries, but it might take a little while… Stay tuned.

Red Hat launches MRG. Centeris rebrands as Likewise, updates software. Sun open sources system management code. (and more)

Red Hat’s Linux Automation Delivers 100-Fold Performance Gains with Messaging, Realtime and Grid Technologies, Red Hat (Press Release)

Centeris is now Likewise Software; Announces Availability of Likewise Enterprise 4.0, Likewise (Press Release)

Sun Releases Sun xVM Ops Center For Automated Datacenter Management, Sun Microsystems (Press Release)

MADE IN IBM LABS: IBM Contributes Framework to Eclipse Foundation, IBM (Press …

SURFnet, a Dutch provider of Internet connectivity and innovative security, authentication, authorisation, group communication and video services to higher educational and research organisations, has integrated the MySQL Cluster database into the core of its SURFfederatie service.

What is the optimal OS partition layout for a database server?

I’ve seen so many different configurations for OS partitions of recent time, none to my satisfaction.
Historically, in Unix days 20 years agao, long before RAID and SAN’s all my experiences were for strongly defined partitions.
That is separate partitions for the OS /, /boot, /tmp, /usr, /var and then seperate partitions for effectively application and data with /home and /opt

Today what is optimal for an OS configuration on a database server.
I’m seeking the input and experiences of the community. I’m making the assumption of at least RAID 1 or better for all disks.

It’s obvious that the database partition must be separate, and given snapshot capabilities both the data and binary logs should be specified on the same partition for consistency.
It’s also obvious the /tmp filesystem should not be with the / file system. You …

MySQL AB announced today that Axway, the leading global provider of Collaborative Business Solutions, and a subsidiary of the French Sopra Group, has chosen to integrate the MySQL Embedded Server into its Synchrony global platform.

MySQL will be hosting its first-ever Federal DBA Day - a free, one-day boot camp for experienced Oracle DBAs interested in learning how to deploy and manage MySQL in a production environment. The event will take place on Thursday, January 24, 2008, at the Ronald Reagan Building and International Trade Center in Washington, D.C. For more information and to register, visit: http://www.carahsoft.com/events/mysql/01-24-08/mysql01-24-08.php?ref=mysql

Over at ITToolbox Tarry has another blog . He posted an article where he tried to debunk some myths about open source. I feel he needs some help there :)

Let's start with his second Myth , Open Source is Free. Off course it isn't , you need to invest your own time to get familiar with it or pay other people to use it. Compare it to building a house ... you can build one if you have the skills and the time , but you still need to pay for the bricks and the mortar, or you can pay someone who has the skills to build one for you. With software there used to be a similar thing. You could buy software, then install and configure it yourselve, or you could hire someone more skilled than you to install and support it when you run into problems. Now take away the fact that you have to …

Dear lazyweb,

I want to mine a code repository for data to map past bugs to sourcecode files.

I have written a small PHP script (the initial version of the script can be found here) to import the relevant data from a Subversion repository into the following tables of a relational database:

bugs            changes         paths
--------        --------        -------
bug_id          path_id   <-->  path_id
revision  <-->  revision        path

What I need now is two queries to ask the database for

• paths that are most commonly changed during bugfix commits and
• paths that are commonly changed together …