Does anyone have a link to a decent comparison between MySQL and PostgreSQL? I'm really wondering why so many people use MySQL, even though it supports a lot fewer SQL features than PostgreSQL.
Robert Haas, a Postgres committer , occasionally blogs about comparisons : http://rhaas.blogspot.com/search/label/mysql
Theres also http://www.wikivs.com/wiki/MySQL_vs_PostgreSQL
Historically , MySQL has been more widely available on low end web hosting plans, so its what a lot of people first use when they start using databases, and a lot of web apps, such as Wordpress, support it exclusively.
Until a year or two ago, only MySQL had built in (if occasionally fragile) replication which made it popular for that reason alone. Postgres now has robust replication, with new features coming down the pipeline soon : http://www.depesz.com/2011/07/26/waiting-for-9-2-cascading-s....
I prefer Postgres, but oddly enough under Oracle theres been some interesting features added to MySQL, which is good for both.
Also, MySQL got commercial entity behind it in its early days which promoted it a lot. In addition, it worked an all platforms, including windows, while Postgres was there just in last couple of years.
I cringe every time I read that. MySQL replication is many things, but it is not reliable (as anyone who has used it at scale will confirm).
I think the only reason this myth prevails is because hardly anyone ever actually verifies if their master/slave are in sync. A table checksum can be a real eye-opener here, especially on a deployment that's been running for while and undergone schema changes, restarts, network splits, etc.
PostgreSQL's built-in replication is pretty easy to set up[1] and provides a writable master, and a cascade of slaves. Slaves can be synchronous or asynchronous, and the synchronicity can be turned off per transaction.
[1] http://www.depesz.com/2011/01/24/waiting-for-9-1-pg_baseback...
MySQL is good enough so there is no need to migrate applications for a few additional features.
In the Windows world the same is true of SQL Server -- the setup, connectivity, and basic usage is so incredibly easy that it made it the first choice of many teams.
This seems incredible -- that products are chosen on such an irrelevant-in-the-long-term basis -- however it has proven true across almost all of the computing market, even targeting highly skilled developers. PHP has few competitive merits, yet it was the default option for many because it was so easy to make something basic in.
There's a lesson there in that.
I don't think there is anything too incredible in that. If you want to throw together an idea quickly, get it out there and test response then use whatever technology gets the job done quickest. You can always change later.
Why waste huge amounts of time setting up a technically perfect database for a product it turns out no-one wants?
The same is true with many technologies and approaches. Projects that consume thousands or tens of thousands of hours, with a toolset chosen because it represented an outset savings of single-digit hours.
Changing in the future is seldom as easy as it seems in those early days.
Yes and no. There are a vastly more hosting options that provide MySQL vs Postgres. So it's not an issue of getting competent with the DB system, it's an issue of using an existing LAMP stack or having to roll your own.