“Welcome to FOSDEM!” Well, FOSDEM ended on Sunday, but I’d like to provide you with a short recap of my Q&A and Roadmap presentation. Warning: I may go into more visual detail than verbal. This is because reports from the community, OlinData and Philippe Back as well as twitterings by Ulf Wendel already post most of what I said. It’s because my presentation (1.5 MB) is posted on MySQL Forge. And it’s because those present are waiting for the following level of detail of …

This is the first public release. Features:

• Top Queries - See which queries are being run the most on your server.
• Top Users - See which users are using your server the most.
• Top Tables - See which database tables are opened the most.
• Top States - See which states your database is most busy doing, such as creating temp tables.
• Replication Profiling - You can measure how much capacity you have left on the replication SQL thread on slaves. If you are using MyISAM a lot, a MyISAM lock analysis will help discover any locks associated with replication, as well as lock-prone queries in general.
• Query Ratings and Visualization - You can get your queries rated using EXPLAIN and see which queries are …

I ran into a problem today where a web application and a suite of servers relying on a MySQL server were not responding, or responding very slowly.

Upon investigation of the issue, we found a high number of "unauthenticated connections" in the MySQL process list. A common cause of this is that MySQL cannot lookup the reverse DNS of the servers connecting, but it was strange this "suddenly" started happening. The servers in question used private IP addresses in the range 10.10.10.x.

The problem with this is if you do not setup a local zone for "10.10.10.x" reverse DNS, and poison your local caches to force those zones to be looked up locally, it heads out to the global internet to try and find a DNS server responsible for the 10.10.10.x reverse DNS (this translates into DNS name x.10.10.10.in-addr.arpa).

Because the root servers spent a lot of time fielding requests for these zones specifically with NULL replies, it was …

As some of you have noticed (and reported) we are having trouble with the CHM builds we do of the various MySQL Reference Manuals.

This is something that we are looking into, but the reasons and issues behind it are complex. One of the basic reasons if the sheer complexity and size of the documents are now building – there are thousands of files in a standard HTML build, constituting more than 2,500 pages of material.

Unfortunately, the final part of the build process, using Microsoft’s own HTML Help Compiler is something we have no control over, and Microsoft no longer support the product. Sometimes it produces a perfectly fine CHM from the source material. Sometimes, using the exact same material, it produces a build that is corrupt in some way.

The CHM building process is automatic – I improved it a couple of years ago to be automated as much as possible using a Windows Powershell script that performs nearly all of …

IP Address Geolocation From MySQL

In this short tutorial I will use a local MySQL database to do IP addresses geolocation.

I’m speaking at the User Conference this year, with a half-day tutorial and three further sessions. The running theme is performance, both in terms of the performance of your queries, and in terms of scaling up.

Scale Up, Scale Out, and High Availability: Solutions and Combinations

This is the big tutorial. It’s difficult to resolve what I’ll be talking about into a few sentences, but think about all of the different technologies available here - replication, partitions, sharding, DRBD, memcached - I’ll be talking about all of them, and more importantly combinations of the different solutions and where the potential performance gains and pitfalls are. I’ll also be using the opportunity to demonstrate some of the more obscure combinations that you can use to provide the environment you need.

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This Thursday (February 12th, 14:00 UTC), MC Brown will give a MySQL University session on Using DTrace with MySQL. MC has been involved not just with documenting DTrace but also with DTrace development; see his recent blog post for details.

For MySQL University sessions, point your browser to this page. You need a browser with a working Flash plugin. You may register for a Dimdim account, but you don't have to. (Dimdim is the conferencing system we're using for MySQL University sessions. It provides integrated voice streaming, chat, whiteboard, …

Last month, the local Sun office was gracious enough to host the local MySQL Meetup. My attendance has been sporadic last couple of years (57%, apparently), largely due to travel, but this time I committed to giving a talk on MySQL 6.0 and Falcon.

It was a great meeting with excellent turnout--thirty-one, I think, including three from Sun/MySQL.

Benjamin Wood, a systems engineer from Dallas, called in to give a MySQL 5.1 overview, including a nice drilldown on the new features from which I learned a few things myself.

Prior to joining Sun last May, Benjamin had 12 years experience as an Oracle DBA, which gives him substantial database street cred and the ability to speak with some technical …

UFS has been the main filesystem on Solaris until the arrival of ZFS in 2004. UFS has been around since the SunOS 4.x days and is still quite widely used on Solaris. Although OpenSolaris uses ZFS by default, many database users have mostly used UFS.

UFS is a buffered filesystem because by default it uses free memory to cache data. While buffering is useful for a large number of applications, database users have generally stayed away from it by using DirectIO. If you are using UFS with MySQL, you have the option of using UFS buffered or UFS DirectIO. In this blog I will try to describe some of the reasoning behind why UFS DirectIO should be used with MySQL.

Buffered UFS Limitations (with MySQL/InnoDB)

UFS buffers filesystem data using 8K pages (4K on x86) in the buffer cache. Innodb stores records in 16K size pages and issues reads of size 16k. This corresponds …

Error handling implementation in Windows database applications is a must for any Application Developer today. The main idea of error handling is to avoid application crashes by finding out the occurred errors and fixing them. Different programming languages have different ways of implementing error handling. Microsoft Visual Basic .NET (VB.NET) is the most common programming language for developing windows database applications today. VB.NET codes are provided in many websites, books and materials without error handling implementation. In this article I would like to introduce you to the basics of error handling implementation in MySQL/VB.NET windows database applications. I’ll be covering structured exception error handling, which was introduced for the first time in VB.NET 2002. I will also go over the latest technologies of disposing unmanaged recourses in .NET Framework with the Using statement. To write exception errors to a log text file, a …