Last week I was working with a client that rediscovered a bug where setting expire_logs_days and issuing a flush logs causes the server to crash. It’s MySQL Bug #17733 if you want to have a look. Seeing MySQL crash was enough inspiration to fix something that I and others have wanted to fix in MySQL for years.

Currently a flush logs command tries to flush all of the following logs in order:

• General Log
• Slow Query Log
• Binary Log
• Relay Log
• Store Engine Logs (If available)
• Error Log

The reason I wanted to fix this is because my client was issuing a flush logs to rotate the error log on a server with no replication. The crash was caused by replication. With individual flush logs it’s less likely for this to happen again in the future. People can simply issue a query for the …

So today Roman, one of the developers on the Doctrine project, pointed me to an article that was discussing the misuse of DISTINCT. This article went so far as to say that "A SELECT DISTINCT query is frequently a "code smell". The article pointed to another article hosted at onlamp.com. That author was advocating the use of subqueries to more efficiently filter out redundant rows. Immediately I began to wonder if this is really a feasible approach since MySQL's subquery handling is very slow. I could imagine this being faster on RDBMS where the subquery implementation is more mature. That being said comments in the onlamp.com article point to the fact that even on Oracle things get slower with the …

This is just a very short note about the recent license change from LGPL to GPL made by the author of extJS. When choosing an open source product make sure that the contributors are fragmented across enough organizations to prevent any chance of being able to do a license change. If that is not the case make sure that the community is large enough so that you have a good chance at succeeding with a fork if the need arises. In the case of extJS the later seems to be the case. As such the license change itself is not soooo big an issue, since a lot of people do not consider their frontend code to be proprietary anyways. The source is there for all to see. So for the most part people are fine considering their frontend to be licensed under the GPL. That being said, extJS guys are …

I spotted an interesting blog post over on Planet OSDB about prepared statements gotchas. It illustrates very well the issue that prepared statements have been plagued with since their inception: namely that they can severely hurt performance (even though they are considered to improve performance by most people).

Just briefly: Why do we even care for prepared statements? For stateless web applications the benefits are mainly protection against SQL injection and better readability. In some rare cases in theory also better performance if the same statement is executed multiple times in the same request. The disadvantage is that for most web applications queries are rarely executed more than once and therefore the separation of parsing/planning and execution just means that there is an …

JavaOne wrapped up on Friday. We hosted individuals from across the globe, and from every industry: consumer electronics and gaming, to enterprise IT, space exploration, factory automation, the automotive industry, academia - like the network itself, Java delivers something for nearly everyone, everywhere.

This year's biggest announcements centered around Java's role in the future of rich internet applications (or RIA's). What's a rich internet application? It depends on your perspective - from mine, it's any network connected application that persists in front of a user, typically outside a browser, that can operate when disconnected from the network.

On the one hand, I'd claim Java's always been a RIA platform - before the world really wanted one. Early Java applets delivered interactivity, but at the expense of development complexity and, in the early days, performance - when a browser, and more recently Javascript, would …

So it seems that Sun has made it clear that the core product will remain open source. Of course the definition of what is core and what isn't is up to Sun/MySQL to decide, but it seems that overall more things will be released as open source than if MySQL would have gone through with its planned IPO. So this is a good thing. Speaking of non core products, I really like what Mike and his team are doing in the GUI department with the workbench and their other GUI tools. However since Sun is friendly to PostgreSQL and actually also distributes SQLite (its …

We made some big announcements this week at our annual developer forums, CommunityOne and JavaOne. I thought I'd highlight a couple in particular.

We announced the first commercial release of OpenSolaris - targeting high speed developers and development teams (not consumers...). OpenSolaris focuses on developers wanting to be freed from proprietary software models, who see innovation and automation in operating systems as a source of competitive advantage.

If Solaris 10, OpenSolaris's older brother, is for IT departments prioritizing carrier grade stability over rapid innovation, OpenSolaris targets the exact opposite - developers, from high performance computing to social networking, that prioritize a constantly refreshing repository filled with community innovations (and ZFS-based automated rollback) over an unchanging qualification …

We announced the results of our third fiscal quarter (Q3) on Thursday last week, and the results weren't what I, or any of us, wanted.

As you can read in the press release, we delivered $3.267 billion in revenue for Q3, roughly flat with a year ago. On that revenue, we delivered a GAAP loss of 4 cents (equal to the charge associated with the acquisition of MySQL, which closed within the quarter) - on that revenue, we generated around $320m in cash.

The low light of the quarter was revenue in the US - which declined year over year by nearly 10%, a big step down for a geography that typically contributes 40% of our total revenue. The highlight of the quarter was our India performance, up 30% year over year - and our chip multi-threading Niagara systems, which grew (billings) 110%.

We had growth in 12 of 16 geographies …

At the 2008 MySQL Conference and Expo, the closing keynote was Jacek Becla speaking on "The Science and Fiction of Petascale Analysis". See the slides on the Forge at http://forge.mysql.com/wiki/MySQLConf2008ThursdayNotes#The_Science_and_Fiction_of_Petascale_Analytics