Today's pearl of wisdom:

MySQL dump files, as produced by mysqldump, are not text files.

A common mistake is to think that mysqldump files are text files. While they superficially look like text files, they in fact are not. This leads to confusion and problems if people try to edit them in a text editor application, which will in many cases cause corruption.

MySQL dump files contain the SQL commands required to recreate the contents of a database (or subset thereof). However, these are SQL commands in arbitrary (binary) encoding and can consist of a mixture of different encodings (e.g. if you have BLOBs). This mixture is not safe to edit with a text editor, which expects a text file to contain character data in exactly one encoding (and will typically guess, ask the user or just use its default to determine which).

Suppose you use utf8 data in your database - then your mysqldump file …

I have finally managed to watch and slightly edit the September 2007 Boston MySQL User Group presentation I did on the MySQL Proxy.

It's geared towards beginners, and has lots of examples, including explaining some of the examples that come bundled with the MySQL Proxy.

Direct Play

Download video (.wmv file, 612 Mb)
Download video (.wmv file, 76.10 Mb)

Enjoy!

Some resources:
Presentation Slides PowerPoint (ppt) or PDF or …

For those who missed the previous announcements, MySQL University is a series of online expert lessons that you can join for free and attend from the comfort of your home or office. The slides are provided in …

I spent way too much time this weekend trying to get the pager stuff in Drupal working for a module I`m playing with.

I had learned a lot from the watchdog module on how paging was supposed to be working and I was trying to do the same with another database. As I got a page limited by the number of records I wanted but I couldn't find any of the fancy next, previous and page number thingies that I wanted.

The watchdog module worked for me and I started stripping the watchdog module till I could actually replace my function with watchdog_overview function. Even replaced the watchdog query with my qeury.. but not such luck.. I couldn't get $output .= theme('pager', NULL, 50, 0); to work.

So as every open source geek does.. I started looking into the code. pager.inc
The header told me the author.. I could mail him and wait …

Arjen wonders why the MySQl Cluster Study book is published on Lulu and not trough MySQL 's traiditional publisher.

Altough I was involved in the creation process of the mentionned book, I have no idea why this decision was made but to me it makes perfect sense. MySQL Cluster is a piece of software that is still going to change a lot in the next couple of months and years.
A book published in a traditional way needs a minimal sales volume in order to be worth publishing. If there even is a slight chance that by the time the book gets published a significant amount of content of the book has already changed traditional publishers shouldn't publish the book. Now over at Lulu.com a book won't be print before a customer orders it. So when the book is being sent to me. I get the current version of the book.. If in 3 months the authors decide to rewrite a chapter or …

While researching partitioning performance (expect an article about this topic soon) I come across the news that the Falcon team has released a Falcon Feature Preview with the latest implementation.
The test I was running was based on 9 server instances , using different combinations of MyISAM, InnoDB, and Archive, with and without partitions.
Since I was at it, I quickly added three instances of MySQL 6.0.4 with Falcon (MySQL Sandbox is really handy in these cases) and added Falcon to the test bench.
As I expected, partitioned Falcon is not particularly impressive, but there was a serendipitous result. In addition to large data warehouse oriented queries, the test fires also 180 OLTP queries, with warm indexes, i.e. after the indexes have been …

One of the concepts of clustering, is that the secondary node may need to stonith the primary node in a forced take over in order to make it give up shared resources. This works great on more expensive hardware that has a management interface like IPMI, but my 'toys' budget is a little more limited.

It's equally possible to just cut the node off at it's power source. Does anyone know of a (cheap) power strip with a serial[1]/usb[1]/network interface where I can send signals to cut off individual ports power?

If I can't switch off individual power ports, I will need to buy two and have the nodes each manage the opposite node's power.

[1] If it's serial or USB I'll need to use a third node as a proxy to the device, which is annoying, but quite possible.

Hmm, dunno if anyone else spotted this interesting tidbit... the new MySQL Certification study guide, the one on MySQL Cluster, is made available via Lulu: http://www.lulu.com/content/1297960

MySQL AB used to have a deal with Pearson, branded as MySQL Press.
Lulu.com on the other hand is a self-publishing system.
I've seen other Lulu books, the printing and binding is quite excellent. No worries there.

But what this means is that apparently the Pearson deal ended somehow and MySQL AB hasn't got another publisher. I find that a bit curious. The problem is of course that now you're not likely to see this study guide appear in any shops. Online is fine, but shop-based distribution doesn't hurt, particularly with the "competition" databases having plenty of related books on the shelf. Diddums for Amazon & co, it's now just not there. So people …

Inside of libmemcachd (aka the library behind the memcache engine for MySQL) I have a big stack of hash algorithms you can pick to use. libmemcached splits hashing into two concepts.

Hash used for key distribution
Algorithm used for distribution

For the hashing there is a default method that I use. It is pretty generic in nature. There are two other primary methods are MD5 and Hsieh.

So what does the performance look like for each of these?

Default:
Testing generate_data                           14.183
Testing get_read                                     11.144
Testing mget_read                                        1.992
Testing mget_read_result …

At MySQL I'm writing several different command-line applications from the MEMo Agent to the MySQL Proxy. They all have a common set of requirement:

• command-line options
• config-files (mapping cmd-line options to config-files)
• logfile handling (syslog, SIGHUP, ...)
• a mainloop (SIGINT, CtrlHandler, ...)
• daemonizing (daemonize, services, ...)
• plugin handling

In the proxy svn you see all this a the chassis of the proxy.

At the side it has a MySQL-Server and a MySQL-Client (we usually call it the proxy). Currently this is implemented as libmysql-proxy which is then used by the proxy plugin to implement the proxy.

By splitting up the design into 3 different layers:

• chassis
• low-level protocol + protocol states
• proxy implementation as plugin

we can

1. use the …