In December 2007 Werner Vogels posted a blog article entitled Eventual Consistency, since updated with a new article entitled Eventually Consistent - Revisited. In a nutshell it described how to scale databases horizontally across nodes by systematically trading off availability, strict data consistency, and partition resilience as defined by the CAP theorem. According to CAP, you can only have two of three of these properties at any one time. The route to highly available and performant databases, according to Vogels, is eventual consistency in which distributed database contents at some point converge to a single value but at any given time may be …

SQL and Relational Theory

SQL and Relational Theory How to Write Accurate SQL Code by C. J. Date, O’Reilly 2009. Page count: 266 pages of “real” text, plus hefty appendixes. (Here’s a link to the publisher’s site: SQL and Relational Theory How to Write Accurate SQL Code).

This is a very important book for anyone involved with databases. Before I say why, I need to apologize to Mr. Date. I tech-reviewed part of the book and did not care for it. I am afraid I was quite a curmudgeon in my review comments. So, Mr. Date, if you’re reading this — I want to say I …

Well, I'm somewhere between Toronto and Detroit on a VIA train speeding along soggy and grey Ontario which is trying to wake up from the doldrums of winter. It's not a pretty sight.

Friday night I was shocked and amazed to have 20 students show up to the presentation at McMaster, after all, Friday night I thought would have been a death knell for any boring tech talk from yours truly. I suspect that the copious amounts of pizza provided by Sun might have had something to do with it.

Like London, the talk in Hamilton was a success due in no small part to the organizational abilities of the McMaster Sun Campus Ambassador, Bhavin Mehta (who I later discovered was given an award for being outstanding as a Sun CA, and had organized this to be right after his graduation ceremony - now *that* is dedication!).

Topics for the evening, again how MySQL could possibly make money by being open source, the difficulties …

So we have already looked at sysbench & dbt2 tests… now we have to look at the new Juice DB benchmark. Juice runs a series of queries generate its load, these queries are combined into a workload. I tested the v1010 with a mixed workload ( mix of short & long updates and selects ), a mixed simple workload ( mix of short running updates and selects ) , and a read only ( selects which are designed to hit the disk ) . Because this is still an evolving benchmark I am including results from an Intel MLC drive (note these boxes are vastly different).  Keep in mind this is not a completely fair comparison. The Intel drive is not the enterprise class drive, but even with the SLC drive I don’t think its a fair comparison. The price difference between these two solutions is ~$50/GB -vs- ~$12.5GB.

The setup for this test created about a 20GB database, with each of the 3 large tables coming in around 6 GB each. I tested primarily with a 768M …

Just released 0.7 of the SabreDAV library. This release implements some of the more obscure WebDAV features, and a plugin system.

Some changes:

• Basic plugin system.
• Comes with a plugin to display html indexes for browsers.
• Sabre_DAV_FilterTree is now Sabre_DAV_Tree_Filter.
• Sabre_DAV_TemporaryFileFilter is now Sabre_DAV_Tree_TemporaryFileFilter.

Full changelog.

Any help is greatly appreciated. I'm finding this taking up a large amount of my free time, so anyone interested in documenting, fixing bugs, writing tests, implementing additional webdav rfc's, making logo's definitely send a message to …

As mentioned previously, Monty Widenius is starting his new company based on some interesting premises. With Zak Greant they have co-authored a pamflet where they outline a blueprint for Open Source companies. In many ways this could be considered the "Dogme 95" of Open Source businesses:-)

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This latest change also means that MySQL Sandbox will be available through the CPAN (Comprehensive Perl Archive Network, for the uninitiated).
The next step will be to include this package in Linux distros (Ubuntu, …

Quick note I got memcached 1.3.2 working with waffle. I added a lot more code then I needed, and I think I may be able to get this down to a 1 or 2 line patch… In case your interested in a slightly bloated waffle version of 1.3.2 its here: https://code.launchpad.net/~yonkovim/wafflegrid/memcached-1.3.2

I will clean this up this week and push a better more streamlined version then.

At least since early 2006, at the MySQL Athens meeting where I first met and listened to Jim Starkey, I have been of the firm conviction that log structured databases will be the future for disc-based storage devices. Their largely sequential write pattern ideally suits modern drives which are optimized to write whole tracks of data at a time. I even proposed such a project to Monty and Brian at