I've just read through this document:MySQL vs PostgreSQL and it's obvious paragraph after paragraph that PostgreSQL is the better database. Performance, features and community are all in PostgreSQL's favor. There is almost nothing in MySQL's favor apart from obscure things like faster
count(*) (without conditionals) and built in replication support. In the last two weeks I've also had the great fortune of playing with full textindexing in both MySQL and PostgreSQL and again, MySQL sucks ass and PostgreSQL (8.3) is really impressive and fast. (I've used both databases quite extensively over the past 8 years as a web developer)
I once heard that Google uses MySQL for its user database with a custom built transaction machine. And I read that Google engineers had donated some great code to the MySQL project. But why do they bother? What do they know that other engineers don't? And why is MySQL so popular with cheap stack-em-high LAMP hosting sites?
I do understand that PostgreSQL came off a bad start 5 years ago(ish) when it didn't support Windows which meant that newbies had to use MySQL and that stigma is still lingering but that was a very long time ago.
I guess it takes a lot of convincing to switch from one technology to another once you've set your mind on something. That's why we're human. A proof of this is shown if you scroll down to the bottom of this page there's a little simple survey and despite being on a long article with objective convincing arguments that PostgreSQL is better MySQL is doing quite well. Why?