There is no "first" or "last" aggregate function in SQL. Sometimes you can use MIN() or MAX(), but often that won't work either. There are a couple of ways to solve this vexing non-relational problem.

First, let's be clear: I am posing a very non-relational problem. This is not about the minimum, maximum, top, most, least or any other relationally valid extreme in the group. It's the first or last, in whatever order the rows happen to come. And we all know rows aren't ordered -- in theory. But in practice they are, and sometimes you need the first or last row in a group. This article shows how.

Last week I noticed a blog port by Morgan Tocker on "Big transactions
suck.."

http://mtocker.livejournal.com/30197.html

His post made me think a bit about Innodb's behavior both in cases
where user's use small numbers of transactions, and the case where
user's write applications that connect and then disconnect from the
database.

The connect/disconnect data came out as I expected it. Reconnecting
to the database can cost you in performance. In each of the cases
below the test was run with an increasing number of users.

The commit vs autocommit was bit more interesting. From the graph I
can't find any discernible pattern showing which might be better
(though this highlights that I need to add standard deviation to
mysqlslap so that I can tell if the …

Got back from the MySQL DBA boot camp in San Francisco. Very nice one-day class, covered a lot. Kudos to Ronald Bradford; he did a great job of it. Good to get a free copy of the MySQL 5.0 certification guide and free passes to the certification exams. Now I have no excuse not to get certified… A lot of it I knew already (from having done this for some months now), but I especially enjoyed the section on tuning, and got some good tips throughout.

One question came up that is to the point of this site: where should an Oracle DBA start? Check out Ronald’s excellent and thorough answer at his site, in his post, “Learning MySQL as an Oracle DBA“. Certainly could not have said it better myself.

I've been thinking about this today. My attempts thus far to write random queries which stress various parts of the server have worked, and served a purpose - but have been rather huge and clumsy.

For example a 5 union select, each comprising of 7 joins did have it's value.. The problem with huge random queries is simply that the results cannot be verified as easily as they were constructed (unless you run the same on various DBMS). These huge tests are mostly only good for checking if the server crashes.

Now, I wish to try write testcases that have these properties:

• small
• results are self-verified
• each test is random, but reproducible given a seed value
  

Tonight I'll throw together a code-generator to do simple insert/select and post any interesting results here later.

MySQL Connector/Net 5.0.8 a new version of the all-managed .NET driver for MySQL has been released.  This is a bug fix release for the current production branch of Connector/Net.  Version 5.0.8 is suitable for use with any MySQL version including MySQL-4.1, MySQL-5.0, MySQL-5.1 beta or the MySQL-6.0 Falcon "Preview".

It is now available in source and binary form from the Connector/Net download pages at http://dev.mysql.com/downloads/connector/net/5.0.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.)

We moved to a new installer technology for this release.  Please let us know what, if any, problems you have with it.

The full release announcement with change …

Stephen O'Grady, analyst over at RedMonk, has a good posting on how open source companies are coming up with new revenue streams based on automated services. As Stephen points out, we've gone from "How can you make money from open source?" to "How do you make more money?" With companies like Red Hat, MySQL and others, the first question has largely been answered. But there are many ways to skin a cat, so it's worth considering what additional ways open source companies can make money. Stephen gives examples of value-added services including Red Hat Network, Red Hat Exchange, MySQL Monitoring... READ MORE

Have you ever been annoyed about the input and output binding that is part of Prepared Statements? Prepared Statements have their room in PHP and MySQL[i] for some good reasons. Though, I recall that I didn’t like the output binding when I tried them for the first time. I wanted the good old mysqli_fetch_assoc() to be available. Last year in November someone, I think it was Lukas (but don’t blame me, if I’m wrong), suggested to implement mysqli_stmt_get_results() with mysqlnd.

By help of the new function, you can create a …

Have you ever been annoyed about the input and output binding that is part of Prepared Statements? Prepared Statements have their room in PHP and MySQL[i] for some good reasons. Though, I recall that I didn’t like the output binding when I tried them for the first time. I wanted the good old mysqli_fetch_assoc() to be available. Last year in November someone, I think it was Lukas (but don’t blame me, if I’m wrong), suggested to implement mysqli_stmt_get_results() with mysqlnd.

By help of the new function, you can create a …

original post
second post

http://consoleninja.net/code/dpm/rel/dpm-r1.tar.gz - release 1 of DPM, tarballed sources. Also available via cloning git and tracking the 'release-1' tag

git clone http://consoleninja.net/code/dpm/dpm.git - to get the latest code, always
http://consoleninja.net/code/dpm/dpm-export.tar.gz - a tarball of the latest code, for those unwilling to git it.

I'd still call this a preview release, but it's too juicy to not release in some form. Early and often, right?

This is the first …

original post
second post

http://consoleninja.net/code/dpm/rel/dpm-r1.tar.gz - release 1 of DPM, tarballed sources. Also available via cloning git and tracking the 'release-1' tag

git clone http://consoleninja.net/code/dpm/dpm.git - to get the latest code, always
http://consoleninja.net/code/dpm/dpm-export.tar.gz - a tarball of the latest code, for those unwilling to git it.

I'd still call this a preview release, but it's too juicy to not release in some form. Early and often, right?

This is the first …