Schlomi Noach recently wrote a useful primer on the depth of B-trees and how that plays out for point queries—in both clustered indexes, like InnoDB, and in unclustered indexes, like MyISAM.  Here, I’d like to talk about the effect of B-tree depth on insertions and range queries.  And, of course, I’ll talk about alternatives like Fractal Trees, since that’s the basis of Tokutek’s storage engine for MySQL.

Please see Schlomi’s post for details, but I can summarize a few points, partly because I need some vocabulary for the points I’d like to make below.  Scholmi notes that there are two main features determining the depth of a B-tree (or B+-tree):

1. 
   
2. The number of rows in the database.  We’ll call that N.
   
3. The size of the indexed key.  Let’s …

MySQL Connector/Net 6.0.3, a new version of the all-managed .NET driver for MySQL has been released.  This is the first GA release of the new 6.0 connector and introduces several new features and enhancements.  This release is approved for use in all scenarios and officially supports MySQL servers 4.1 and higher.   We had three major goals with this release:  speed, entity framework support, and a better Visual Studio experience.  I'm happy to report that we have met all three.

It is now available in source and binary form from [http://dev.mysql.com/downloads/connector/net/6.0.html] and mirror sites (note that not all mirror sites may be up to date at this point of time - if you can't find this version on some mirror, please try again later or choose another download site.)

Fixes from 6.0.2

…

MySQL Connector/Net 5.2.6, a new version of the all-managed .NET driver for MySQL has been released.  This release is of GA quality and is suitable for  use in production environments.  We strongly urge you to  review the change log that is shipped with the product for a thorough review of the changes.

We have a ton of fixes in this release so please review the changelog and see if your favorite bug has been fixed.  This version officially supports all versions of MySQL from 4.1 and later.

It is now available in source and binary form from [http://dev.mysql.com/downloads/connector/net/5.2.html] and mirror sites (note that not all mirror sites may be up to date at this point of time - if you can't find this version on some mirror, please try again later or choose another download site.)

Changes since …

Over 300 exams were taken at the 2009 MySQL Users Conference. Many more DBAs were certified this year then last and the Developer cert was not as popular.

We had problems with network bandwidth (Thanks to Patrick at O'Reilly for getting us more as soon as he could) and some software glitches with the new software. Some folks asked to take their exam at a location with better bandwidth and their results are still trickling in to the Certification Team.

The new 5.1 DBA exam was offered and the general review is that it is a much more realistic test of a DBA's skills than the older version. There were a few edits that did not make it into the system that cause some confusion but those taking the exam carried on bravely.

Thanks for all who made the journey to the Magnolia room, especially those who made it through the 1,200 teenagers who showed up for the conference after ours!

In a blog post today, Stefan of the MySQL documentation team says that the MySQL documents will not be open sourced. Now, I have to go back and review the MySQL CE Keynote that Karen gave, but I'm pretty sure she said to the audience that it was "going to happen". Why would she even bother bringing it up in the keynote if it was never really being considered anyway? There has been little community input on this, and I for one am outraged that a GPL product would not release the documentation as GPL too.

I'm now totally convinced that MySQL does not understand, and will never understand the MySQL community.

Is this an opportunity for Oracle to try to stall community participation in MySQL? I don't want to be paranoid, but this could just be the hints of bold new changes in MySQL strategy, especially considering Karen's …

We’re proud to announce that the new version of Kontrollbase is available for download. The enterprise MySQL database monitor and analytics application has been getting a lot of improvements and bug fixes since our initial beta release. Included in this release is an improved web-based installer, socket options for the client server connections, more troubleshooting solutions in the documentation, and some JSON fixes for form submission reporting. You can read more about the full features here: http://kontrollsoft.com/software-kontrollbase and download the new release here: http://kontrollsoft.com/software-downloads

If you are using the scripts from the Configurator (and yes, the broken link is now fixed so it is actually possible to get the config package..), and want to tweak your configuration on a started Cluster then you can do like written below.

There is also a new script in Configurator 2.2 (released 28th April 2009, PST1153AM , GMT07:53) that lets you check the values of different config parameters. Its use is described below.

Pretend we want to extend the DataMemory from 1024M to 1536M:

1. cd mysqlcluster-70/cluster/scripts
2. vi ../config/config.ini
   This is the master config.ini file and will be copied out to the management server(s). Don't change /etc/mysql/config.ini, as that will have no effect.
   
3. Set DataMemory=1536M …

Today we glad to announce release 1.0.3-5 of our XtraDB storage engine.

Here is a list of enhancements in this release:

• move to MySQL 5.1.34
• removed rw_lock patch, so we now use Google's rw_locks
• fix crash after upgrade 5.1.31 -> 5.1.33
• fix mysql-test

Percona XtraDB 1.0.3-5 available in source and several binary packages.

XtraDB is compatible with existing InnoDB tables (unless you used innodb_extra_undoslots) and we are going to keep compatibility in further releases. We are open for features requests for new engine and …

A little challenge for you… given an existing app that does not know about separate master/slave connections, and you want to enable working in a replicated infrastructure. Simply redirecting all SELECTs to the slave connection will not work. Why?

Hint: there are at least two reasons, depending on other factors. There may be more.

Comments are set to be moderated so providing answers will not spoil it for others. I’ll leave it run for a bit and then approve all comments.

I saw something interesting today when helping out someone on the #mysql IRC channel. It was a cnf file that was designed to destroy a server. Before I get into the why-not, here are the goods:

...snip...
read_buffer = 128M
join_buffer = 128M
key_buffer = 512M
max_allowed_packet = 200M
thread_stack = 192K
thread_concurrency = 8
thread_cache_size = 64
query_cache_limit = 256M
query_cache_size = 256M
table_cache = 8192
query_cache_type = 1
sort_buffer = 128M
record_buffer = 128M
myisam_sort_buffer_size = 128M
thread_cache = 64
max_user_connections = 500
wait_timeout = 200
max_connections = 4096
tmp_table_size = 1000M
max_heap_table_size = 1000M
...snip...


Now, you may ask why these settings are bad. I will tell you. First, an equation for calculating per-thread …