JFYI: today I migrated the mylvmbackup source tree from my local Subversion repository on http://www.lenzg.org/ to a Bazaar repository on Launchpad.net.

This will hopefully make it easier for contributors to work on the code and share their modifications with others, removing me as the bottleneck for applying and testing patches for new releases. I chose Bazaar primarily because I wanted to get some more hands-on practice with it, now that the MySQL Server source trees have been transferred to it as well (see Kaj's announcement for …

If there’s one thing that bothers me about using a ready-made solution like wordpress for my blog, it’s plug-ins. I hate software plug-ins. The first question every support engineer for any software product that supports plugins asks in response to a trouble report is “are you using any plugins?” And when you say “yep, I’m using plugins!” the reply from support is to disable them immediately and see if the trouble goes away. That’s a problem.

What’s worse, if the plugins are maintained by a third party (often the case), there’s no telling whether or not they’ll exist when the next version of the base software is released, or whether they’ll be supported in future versions of the software.

Two examples that touch my daily life are Firefox, and …

Server-side Prepared Statements are an outdated technology from ancient times, are they? Brian gives a long list of arguments in his blog posting “Prepared Statements, Musings” why one should think twice before using server-side prepared statements. PDO does enforce the use of prepared statements for all statements which return a result set. Good or bad?

• What are (server-side) Prepared Statements?
• Pro’s and Con’s
• MySQL myths
• MySQL specifics
• …

Server-side Prepared Statements are an outdated technology from ancient times, are they? Brian gives a long list of arguments in his blog posting “Prepared Statements, Musings” why one should think twice before using server-side prepared statements. PDO does enforce the use of prepared statements for all statements which return a result set. Good or bad?

• What are (server-side) Prepared Statements?
• Pro’s and Con’s
• MySQL myths
• MySQL specifics
• …

In yet-another sign of the consolidation of the infrastructure business, Progress Software announced the acquisition of IONA. IONA, with headquarters in Dublin and Boston, was a high flyer in the 90s with the development of the first implementation of CORBA, a key middleware technology for integration. While the company stumbled in later years, they have been retooling around SOA (Service Oriented Architecture) including their open source Artix technology. So raise a pint of Guiness for IONA as it enters into the next chapter of its history. Go mbeire muid beo ar an am seo arís.... READ MORE

I recently filed Bug #37359 filesort can be more efficient based on some performance work with an industry standard benchmark. Read on if the internals of how MySQL implements filesort interests you.

Filesort, as the name implies, is used to sort records when there is an ORDER BY clause in the query. The reason it has the prefix "file" is because temporary files may be used to store intermediate results. filesort() uses a per thread sort buffer of size sort_buffer_size to sort the table. filesort() is implemented in sql/filesort.cc.

filesort may not know how many records need to be sorted. It asks the storage engine for an estimate of the number of records in the table via estimate_rows_upper_bound(). If the number of records that fit in the sort buffer is less than the estimate, filesort will use temporary files to store intermediate results. The flow …

I recently filed Bug #37359 filesort can be more efficient based on some performance work with an industry standard benchmark. Read on if the internals of how MySQL implements filesort interests you.

Filesort, as the name implies, is used to sort records when there is an ORDER BY clause in the query. The reason it has the prefix "file" is because temporary files may be used to store intermediate results. filesort() uses a per thread sort buffer of size sort_buffer_size to sort the table. filesort() is implemented in sql/filesort.cc.

filesort may not know how many records need to be sorted. It asks the storage engine for an estimate of the number of records in the table via estimate_rows_upper_bound(). If the number of records that fit in the sort buffer is less than the estimate, filesort will use temporary files to store intermediate results. The flow …

Server-side Prepared Statements are an outdated technology from ancient times, are they? Brian gives a long list of arguments in his blog posting “Prepared Statements, Musings” why one should think twice before using server-side prepared statements. PDO does enforce the use of prepared statements for all statements which return a result set. Good or bad?

• What are (server-side) Prepared Statements?
• Pro’s and Con’s
• MySQL myths
• MySQL specifics
• …

If you for some reason missed the news yesterday: Symbian, the largest mobile operating system, will soon be Open Source. The software will be made available “over the next two years” and is intended to be released under Eclipse Public License (EPL) 1.0.

Looking at the Symbian press release:

Mobile leaders to unify the Symbian software platform and set the future of mobile free

Foundation to be established to provide royalty-free open platform and accelerate innovation

LONDON, UK; June 24, 2008 - Nokia, Sony Ericsson, Motorola and NTT DOCOMO announced today their intent to unite Symbian OS?, S60, UIQ and MOAP(S) to create one open mobile software platform. Together with AT&T, LG Electronics, Samsung Electronics, STMicroelectronics, Texas …

So I took Roland's comment and tried to get it integrated into my code. For the tab management it worked well, but for portlet management it was a lot harder. Actually I only have a partial implementation finished. What's missing is the necessary logic to be able to move a portlet in the same tab from one column to another (there are 3 columns a portlet can be in for each tab). The thing that was most important to me was cleaning up the pruning operation. This took some trickery (aka hackery). I think its a better implementation but it does make me a bit nervous. Of course its all still very MySQL only.

Anyways so here goes the final query for moving a tab:

UPDATE user_tabs ut
    JOIN user_tabs ut2
        ON (ut.user_id = ut2.user_id
            AND ut2.id = :id
            AND ut2.pos != :pos
            AND ut.pos >= LEAST(ut2.pos, :pos)
            AND ut.pos …