Welcome to the 160th edition of Log Buffer, the weekly review of database blogs.

MySQL

Blame it on MyISAM, says Mark Callaghan of High Availability MySQL, on considering sql_mode and type coercion. “I think that MyISAM has its place,” writes Mark. “It does fast table scans, but InnoDB is much faster on just about everything else. I am just not thrilled with the impact it has had on MySQL.”

Not that those other engines are without flaw. Peter Zaitsev reports on an InnoDB performance gotcha with larger queries.

Here on the …

A broken VIEW was caused by the view’s definer being non-existent. In this particular system, backups are done by replicating all the machines (production, development, test, etc) to one server and doing cold physical backups off that server, which currently has 12 instances running.

So in order to find on what machine the user might still be defined, I went to the backup server. All the data directories are in one path, ie:

instance 1 has a datadir of /data/mysql/instance1
instance 2 has a datadir of /data/mysql/instance2

Now, the unix tool strings can be used against many types of files. In particular, though, you can use strings on the mysql/user.MYD file to see the username, host, and password hash. (note that strings only shows strings longer than 3 characters, so if your host or username is 3 characters or less, it will not show up in the output of strings. You …

In record time, less than a week after the conference (thanks to the free Pinnacle Video Spin and YouTube), all 11 videos that were taken at OpenSQLCamp Europe are online.

For those who missed the sessions, or just want to relive the fun!

Almost all the sessions were filmed; regrettably Darren Cassar’s Securich – MySQL user administration and security made easy! and Stephane Combaudon’s Minimizing data access with covering indexes were not.

The YouTube videos have the descriptions and resources from the official conference pages, and links to pages. If there is more information to add (for example, the slides from a talk are now online), or if …

It’s been just over three months since the April 2009 MySQL Users Conference and Expo. It took a while for the files to be processed, and then uploaded to www.technocation.org, and then I found out that the online streaming was not working properly. So I started playing with things, re-encoding some videos, updating the software, but to no avail.

Just as I was about to give up I got notification that Technocation, Inc. was accepted into YouTube’s not-for-profit program, which allows movies larger than 10 minutes to be uploaded and viewed advertisement-free.

So then I had to upload the videos to YouTube and add descriptions.

So with no *further* delay, here are all the videos from the 2009 MySQL Conference and 2009 MySQL Camp:

The brief description — just the playlists:
Conference …

At the May 2009 Boston MySQL User Group, Giuseppe Maxia of Sun Microsystems gave a presentation about MySQL 5.4 with use cases and benchmarks to show how it outperforms all other current MySQL releases (including the Google patches and the OurDelta/Percona releases).

The slides can be downloaded from http://www.slideshare.net/datacharmer/mysql-54-theory-and-practice

The video can be watched below, or directly on YouTube at http://www.youtube.com/watch?v=giT4SYXuVqA&hl

At the July MySQL User Group, Eric Day and Patrick Galbraith spoke about Drizzle, a lightweight, microkernel, open source database for high-performance scale-out applications, and Gearman, an open source, distributed job queuing system.

The slides can be downloaded from http://www.oddments.org/notes/DrizzleGearmanBoston2009.pdf.

The first hour of video, where Eric and Patrick talk about Drizzle, is at http://www.youtube.com/watch?v=hi4cGzFlcuU, and below:

The second part, about 1.5 hours, where Eric and Patrick talk about Gearman, and then illustrate Gearman and Drizzle working together in a custom search application called Narada, is …

I think many people truly realized how much they take the MySQL documentation for granted during the recent multi-hour outage from mysql.com’s data center. Apparently there is a lot of FUD floating around about the legality of mirroring the documentation, as presented by Justin Swanhart and asked by Mark Callaghan.

The manual page at http://dev.mysql.com/doc/refman/5.1/en/copyright-mysql.html says:

You shall not publish or distribute this documentation in any form or on any media, except if you distribute the documentation in a manner similar to how Sun disseminates it (that is, electronically for download on a Web site with the software) or on a CD-ROM or similar medium, …

OpenSQLCamp 2009 is happening “in parallel to the Free and Open Source Conference 2009 (FrOSCon) on Saturday 22nd and Sunday 23rd August in St. Augustin, Germany …. close to Bonn and Cologne.”

I plan on being at FrOSCon and OpenSQLCamp. Where I go before and after that is up to *you*. Yes, that is right, perhaps I will visit a user group, such as France’s MySQL User Group. Or perhaps your company needs the type of services Pythian can offer — we can do the “traditional consulting” model where we look over your systems for performance tuning and security gains, or fix problems in an emergency. Even more of a win, we specialize in recurring engineering — we can supplement your existing IT staff with database expertise, and do all the database work your current …

I just filed a very annoying bug when trying to compile with plugin engines using the 5.1.xx source tarball.

Description

I am trying to test SphinxSE as a plugin instead of getting it statically linked and came across an annoying bug. When using the configure --with-plugins option only once, the engine is statically linked. When using it twice, the first engine is created as a plugin, and the 2nd one is linked statically. Here are a couple of examples:./configure –prefix=/usr/local/mysql-5.1.33 –with-plugins=innobase –with-plugins=sphinx

plugin_innobase_shared_target='ha_innodb.la'   <-- plugin
plugin_innobase_static_target=''
plugin_sphinx_shared_target=''
plugin_sphinx_static_target='libsphinx.a'       <-- static
./configure --prefix=/usr/local/mysql-5.1.33 --with-plugins=sphinx …

About six months ago, the question of storing images in a database came up. This is one of my favorite topics, and has many database-agnostic parts.

Personally, I think “tell me about storing images in a database” is actually a great interview question, because you will be able to see the difference between someone who has just memorized “what’s right” versus someone who is really thinking. It also helps you see how someone will communicate — if they just say “NEVER do it, it’s as bad as crossing the streams!” then they are a type of person that gives you a short answer, without much explanation, and without many nuances. (That may be what you are looking for, but usually you want someone who gives reasons for why they strongly feel one way or another).

Consider the following cases:

What about storing …