It is striking how much harder it is to make money from open source than to write it in the first place. Open source development is a sophisticated and well-understood social activity. However, the economic model is often laughably primitive: "if you build it, they will come." That applies to the question of turning your open source project into a real job. More interestingly, it applies to the question of how to make open source projects as valuable as possible to the largest number of people. In this post I would like to propose an answer to both questions.

To illustrate open source sophistication, just look how easy it has become to start and manage projects. It is almost a cookie-cutter procedure. You pick one of a number of well known licenses, manage the code on SourceForge.net or Launchpad, communicate with the project …

Every once in a while, I find myself needing to round a number up to the nearest even power of 10, or round a time interval to the nearest quarter of an hour, or something like that. This is actually quite simple, but for some reason I always find myself confused about how to do it. I have to reason it out all over again, instead of just remembering how to do it. Perhaps writing this blog post will help me remember next time.

The basic idea for rounding to whole multiples is to divide the number, losing precision. Then round, floor, or ceiling the resulting number, and multiply to get back to the original magnitude. For rounding to fractions, reverse the process: multiply, round and divide again.

This actually works for any programming language, not just SQL. But I find myself doing it in SQL most often.

Here’s an example of how to turn a year into a decade:

mysql> SELECT FLOOR(YEAR(NOW()) / 10) * 10 AS …

Welcome to the 157th edition of Log Buffer, the weekly, cross-platform review of database blogs.

SQL Server

We start with Michelle Ufford, the SQL Fool, who gives us the poor (wo)man’s graph, a fast and ingenious way to create handsome text-based graphs.

What is the importance of running regular consistency checks? Paul S. Randal returns with some survey results and analysis. He writes, “The results are actually surprising – I didn’t expect so many people to be running consistency …

As well as contributing to the CAOS research practice here at The 451 Group I am also part of the information management team, with a focus on databases, data caching, CEP, and - from the start of this year - data warehousing.

I’ve covered data warehousing before but taking a fresh look at this space in recent months it’s been fascinating to see the variety of technologies and strategies that vendors are applying to the data warehousing problem. It’s also been interesting to compare the role that open source has played in the data warehousing market, compared to the database market.

I’m preparing a major report on the data warehousing sector, for publication in the next couple of months. What follows is a rough outline of the role open source has played in the sector. Any comments or corrections much appreciated:

Unlike other …

Welcome to the 156th edition of Log Buffer, the weekly review of database blogs.

Oracle

Jonathan Lewis gets things rolling with his post, Empiricism. Jonathan asks his readers if an empirical approach to tuning would be appropriate for a particular wait scenario.

Doug Burns was also looking into wait times, beginning, “Sometimes you think a subject is understood so well, including by yourself, that you tend to overlook it until asked to explain it. That which seems intuitive to us …

Here I'm following up my previous post Using linguistic indexes for sorting in Oracle. I don't much like the Oracle solution, that requires creating a special index to speed up sorting, but... at the same time its very powerful, allows to index in many languages and no database changes are needed.

In this post I’ll take a look at the two popular open source databases MySQL and PostgreSQL. I'll take a look only at features, that the database has included and that can be used without any special application changes.

PostgreSQL 8.4

Starting from 8.4, collation (sorting) rules can be defined per database and there is no possibility to set it in session level. All sorting and all indexes are ordered according to the database collation locale. In previous versions there was only one …

Ryan posted an article on the MySQL Performance Blog about how to use mk-query-digest to analyze and understand your memcached usage with the same techniques you use for MySQL query analysis. This is an idea that came to me during the 2009 MySQL Conference, while talking to our friends from Schooner, who sell a memcached appliance.

It suddenly struck me that the science of memcached performance is basically nonexistent, from the standpoint of developers and architects. Everyone treats it as a magical tool that just performs well and doesn’t need to be analyzed, which is demonstrably and self-evidently false. memcached itself is very fast, true, so it doesn’t usually become a performance bottleneck the way a database server does. But that’s not the point. There is a …

This is the 155th edition of Log Buffer, the weekly review of database blogs.

SQL Server

On the SQL Server blogs this week, CSS SQL Server Engineers demonstrated that using DateDiff can query performance problems in SQL 2005 and 2008.

The kind of problems, perhaps, that Linchi Shea examines in his post on linked server security configuration and how it can hurt you. Linchi writes, …

The new Open Source Database Podcast is a companion to the Open Source Database Magazine. Episode one has now been posted and is available for download. For now I am including the show notes below. I will post these notes on the website soon along with all future show notes.

The feed for the podcast is at http://www.osdbzine.net/podcast/osdbpodcast.xml and a direct download of the episode is available here.

Episode Summary

This is the first episode of Open Source Database Podcast. This pod cast is about both open source database servers and the people who develop and use them. The plan is for most episodes to be centered around interviews with various people in the open source community. Kicking …

I just uploaded the pdf of the summer issue of Open Source Database Magazine. Included in this issue:

• A great article on the new features of Postgresql 8.4 by Robert Treat
• Part one of a two part article on Percona’s new XtraBackup backup program

Also the news, the book shelf and Peter Brawley’s Coding Corner. Downloads are available at http://www.osdbzine.net.