This is the second in a series of articles on profiling queries in MySQL. In this article I’ll demonstrate the technique I described in the first article. Note: I wrote this article in 2006, when I didn’t have a clear understanding of even simple concepts such as what performance really is. Since then I have learned a lot from wise people such as Cary Millsap. In 2012 I founded VividCortex, the best database performance optimization and database monitoring platform to chase away the kind of ignorance I display in the article below.

This week I have been spending my time with Mike Zinner, he designs the GUI tools at MySQL. While our GUI tools are beginning to show their age, when is why we are looking at redesigning them, there is one thing that I am very happy about.

Three and a half years ago we made the choice in the interface to create a box that would control what was listed in windows by using a search box. This filtering is very handy when I am looking at large numbers of objects in the database since I can control the list through a simple search.

Why is this coming to mind? I've got a bunch of traveling to do for the next few week and I am playing with my ipod to get more of what I listen to on it. The ipod is only 40gigs and my music/podcast collection hovers around 120gigs. So how to resolve this?

I've added Smart Lists with regular expressions to catch what I want to hear. Music lists create by genre, ratings, and artist. …

While chatting with a few SVN hackers at OSCON, it occured to me that MySQL is the Perl of RDBMS. Discuss among yourselves.

We are currently preparing a MySQL 4.1 to MySQL 5.0 migration. First tests showed a very nasty problem, however.

One of our test cases incorporates queries against DECIMAL columns that use strings as the queried values. In MySQL 4.1 this works flawlessly. The reason behind this is that in contrast to 4.1 the newer server version does a (in my opinion very stupid) conversion from String to double, which in many cases cannot correctly store the precise value.

This may lead to very subtle bugs, especially when using an optimistic locking approach as we do. We only noticed the problem, because we got a ConcurrentModificationException, as an update query that contained a string-ized BigDecimal did not match any rows.

See MySQL bug reports 23260 and 22290 for more details.

Right …

In an article in yesterday’s Süddeutsche Zeitung, an EU Commission source is mentioned as saying “it’s unclear on whose mandate anti-software-patent campaigner Florian Müller is acting“.

Allow me to clarify: On ours.

MySQL AB may be Florian’s first and longest-running sponsor in the fight against software patents. However, financing Florian Müller’s activities in the EU — and on the national level in various European countries — requires a broader group of European companies concerned about software patents in general, and the plans for an European Patent Litigation Agreement in particular. Amongst Florian’s other sponsors, let me mention Germany’s leading Internet provider …

If you've ever created SQL queries with PHP, you probably know what a pain it can be to create insert and update statements. I really, really (really) don't like it. As I was working on my personal site, and exploring possible frameworks to use, I came across CodeIgniter. They have a great database interaction library, especially the function for creating the insert queries.Today, armed with only the descriptions of CodeIgniter's query helper functions, I spent 20 minutes trying to duplicate some the effect of the insert and update functions. I've never seen the code, or even used it, but I didn't have to see the code to write a similar function. Both functions take a table name and an associative array of column names and values. The update function also requires a WHERE statement, and it can't be blank. This is different from CodeIgniter, and that's so you don't accidentally reset all of the passwords in the mysql users table, or any table for that …

Welcome to the fourteenth Log Buffer, the weekly review of the database blogosphere. We start with a couple pieces on Oracle’s purchase of Sunopsis (news item on ZDNet), the latest in a series of purchases for them. On Andy on Enterprise Software offers Andy Hayler’s analysis: Sunopsis’s Data Conductor product is superior to Oracle’s Warehouse [...]

This thread on the Boston MySQL User Group Board is getting interesting:
http://mysql.meetup.com/137/boards/view/viewthread?thread=2280640

(From the original poster:)

I think that nonequivalence comes from the past when the data sharing was a
rare situation. The data changes were always initiated by application and it
always knew about those changes. Now the situation is different. When the data
are shared between multiple remote applications you have to notify other
interested parties about those changes.

Currently databases are mostly used as “pull” components. If they had standard
“push” functionality they could compete with messaging systems with the advantages
of automatic data persistence and powerful query language.

(my response:)
…

When people discuss query optimization on MySQL, or say a query doesn't perform well, they usually mention execution time. Execution time is important, but it's not the only metric to use (or even the best). There are many other ways to measure the work a query requires. This article explains how to really profile a query -- what to measure, how to do it as accurately as possible, and what it means.

This is the first article in a series. In upcoming articles I'll demonstrate some hands-on profiling with concrete examples, and give you a tool to automate the job.

I was really wondered today when I came across really interesting initiative of some women in #phpc IRC channel. They are trying to create some place where PHP women will be able to communicate and feel included in the world of PHP. Ligaya Turmelle (DevZone Roving Reporter) is one of the leaders spearheading the formation of phpwomen.org. She posted an update on their progress her blog recently. She talks about their new website, www.phpwomen.org, their mailing list which can be joined here and their irc channel on freenode.net, #phpwomen. She said:

It is women encouraging women to be active in the greater PHP World. We may be a small group but we have a big impact and are proud of who and what we are. We don’t wish to be exclusive and stand …