SQL Notes

One of the major features in the upcoming 8.3 release is the integration of the tsearch2 full text search extension as a core PostgreSQL feature. While there are no fundamental changes, there are some differences which make upgrading from an existing installation a little tricky. The following are my notes from upgrading a test version of the database which powers this website.

(I'm back in the wonderful world of SQL in general and PostgreSQL in particular after a long hiatus).

Just came across this article describing (briefly) someone's practical experience converting a website backend from MySQL to PostgreSQL, with PostgreSQL coming out faster. Not an exhaustive scientific test, but the comments are interesting reading.

PostgreSQL on Windows: A Primer (via Slashdot)

It's not often that you click through from {insert name of popular Web 2.0 community site here} to {insert name of Web 2.0 startup-type site here} and notice they're running the site on a decently pachydermal database engine, but this one called TrenchMice certainly is.

The site search function is now working properly again. Apologies for the interruption to service - the site software is currently being upgraded and the gremlins are out and about.

P.S. to whoever was looking for "types of aspirin": I know databases can be a headache at times, but pharmaceuticals are usually not the cure.

I've just got back from a few weeks in Thailand doing some consulting work for an international organisation, some of which thankfully involves open source in general and PostgreSQL in particular.

I took the opportunity to poke around the IT sections of a few bookshops and get the impression that the IT book market at least is dominated by publications dealing with proprietary software, mainly Windows in general and as far as databases go Oracle and SQL Server. Books on open source were pretty much in the minority, mainly dealing with Linux and / or PHP. I did find one book each on PostgreSQL and MySQL though, which as far as I could tell were both written in Thailand (i.e. not translations). I can only speculate that the infamous availability of proprietary software at very low prices through, erm, inofficial channels means open source software is at a comparative disadvantage. The current government seems to have issues with open source too, for whatever reason.

 On the other hand, I had to source a dedicated server, and most providers offer Linux as the base package, with Windows servers available at a premium. In several cases the specs for the Linux servers detailed both MySQL and PostgreSQL as "features".

(Apologies to anyone who has sent mails to me in the last month or so and hasn't had a reply, I'm still up to my neck in things to do).

One of the many pitfalls of web-related work is that sometimes you just have to deal with MySQL, as it's the only database option some clients have. Particularly irksome is the penchant many web hosters have for older MySQL versions, which is a major PITA when trying to deal with even slightly complex data.

One of the many things lacking in MySQL is a true boolean datatype. It does possess a pseudo-type BOOL, which is silently transmuted to TINYINT(1), and from 4.1 onwards, to quote the manual, "the constants TRUE and FALSE evaluate to 1 and 0, respectively".

According to the changelog for the 5.1.12 beta release:

Incompatible change: Support for the BerkeleyDB (BDB) engine has been dropped from this release. Any existing tables that are in BDB format will not be readable from within MySQL from 5.1.12 or newer. You should convert your tables to another storage engine before upgrading to 5.1.12.