From Stack Overflow:

Suppose you’ve visited sites S0 … S50. All except S0 are 48% female; S0 is 100% male.

I’m guessing your gender, and I want to have a value close to 100%, not just the 49% that a straight average would give.

Also, consider that most demographics (i.e. everything other than gender) does not have the average at 50%. For example, the average probability of having kids 0-17 is ~37%.

The more a given site’s demographics are different from this average (e.g. maybe it’s a site for parents, or for child-free people), the more it should count in my guess of your …

Last month I spent two days in Belgium, after I got invited to the MySQL distro meeting. It was a non-public meeting with some people from Sun Microsystems and MySQL maintainers from different Linux distributions. It took place directly after FOSDEM (which I unfortunately could not attend due to personal reasons) at the Sun Microsystems Belgium office in Brussels. It was great to meet with Mathias Gug from the Ubuntu Server team in person. He had some really good ideas on how we could reduce the differences between MySQL in Debian and Ubuntu in the future. As a consequence, Debian will soon switch from Subversion to Bazaar for maintenance of …

i read Marks blog entry about fast IO for PBXT, InnoDB (1.0.6 plugin) and MyISAM with some interest.

then there was the durable, not durable and really not durable blog in which Mark and LinuxJedi discussed cluster, and Mark wondered how much IO one could get from 1 data-node with ndb.

so I decided to try.
the setup is similar.
ndb cluster using disk-tables, with a tablespace stored in /dev/shm.

Data occupied 7.3G, which is slightly less than (some of) the others, this is as we don't support having columns with indexes …

If you have been wondering why the overview and graphs pages say “no data to display” on the graphs when you first install Kontrollbase, it’s because there’s no data in the database being returned from the queries that generate the graphs – this is because a new install has no data to graph. This has […]

Celebrating Ada Lovelace Day on the WordPress Publisher Blog, highlighting two women of the WordPress community.

Last week I presented “From support services to software services – the evolution of open source business strategies” at the OSBC event in San Francisco.

The presentation was effectively a work in progress update on our research into the various strategies employed by technology vendors to generate revenue from open source software.

It included a partial explanation of my theory that those strategies do not exist in isolation, but are steps on an evolutionary process, and also introduced our model for visualizing the core elements of an open source-related business strategy.

I provided a number of examples of how the model could be used to compare the strategies of various open source businesses. …

I cannot recall any significant moment of the conferences in 2002 and 2003 (simply because I was not there) but…
In 2005 we had MySQL 5. Peter Zaitsev was still working in the benchmark team for MySQL AB. His presentation on InnoDB performance and tuning was enlighting for many.
In 2006 we discovered the Pluggable Storage Engine API. Jim Starkey joined MySQL AB and we announced Falcon. [A brighter note,] I have been so lucky to meet Paul McCullagh the day before the Conference. Paul is one of the nicest and most brilliant persons I have ever met.
2007 was all around 5.1. We announced the roadmap for 6.0 and our online cross engine backup.
In 2008 we were Sun and for the first time Marten Mickos left his place on stage of the UC to Jonathan Schwartz.
In 2009 we had the Oracle announcement and the Percona Conference. You may describe the conference in many way, it certainly wasn't boring!
And now, 2010. Another …

Master-Master Replication

Creating and maintaining a duplicate copy of a database or file system on a different computer, typically a server.  The term usually implies the intelligent copying of parts of the source database which have changed since the last replication with the destination.

Replication may be one-way or two-way.  Two-way replication is much more complicated because of the possibility that a replicated object may have been updated differently in the two locations in which case some method is needed to reconcile the different versions.

We have seen how the one-way replication works i.e. Master-Slave; here whatever changes are updated on the Master server is replicated onto the Slave server.

Two-way replication i.e. Master-Master replication will be bit different. As the name itself suggests both the servers will be Master to another.

Master-Master replication allows data in …

Very helpful when you need some quick export of a small set of tables and/or data in tables: export SQL dump directly to clipboard, so you can paste it either in a query tab or elsewhere. Implemented in r3206.



Thanks to akrueger for this suggestion!

Most software people are aware of the ACID acronym coined by Jim Gray. With the growth of the web and open source, the scaling and complexity constraints imposed on DBMS implementations supporting ACID are more visible, and new (or at least new terms for known) compromises and tradeoffs are being discussed widely. The better known NoSQL systems are giving insight by example into particular choices of tradeoffs.

Working at MySQL, I have often been surprised at the variety of potential alternatives when implementing a DBMS, and the number of applications which don't need the full set of ACID letters in the strictest form. The original MySQL storage engine, MyISAM is one of the first and most successful examples of an 'ACID remix'. The people …