Stefan Kaltenbrunner has been testing and comparing the latest beta release of PostgreSQL 8.3 against PostgreSQL 8.2 and has some significant results to show. Though the data is anecdotal, the results are fantastic.
Stefan's configuration information and simulation details are in his post, but here is a quote:
The benchmark database is initialized with a scaling factor of 100 (equals to 10M rows) which seems to be a reasonable size for a table in an OLTP style database. All testing was done with 100 clients and 100,000 transactions/client which comes out to 10M transactions and an average runtime of about 1.5 hours.
Nice results. You can see all of the details here.
And be sure to read the comments. Here is a comment from a MySQL person who finally "gets it":
...when I write to the pgsql mailing lists, I get a response--and usually a VERY informed one--within an hour. Often within 10 minutes. Try getting that response time from the MySQL community on their forums online. You're lucky if your thread gets answered in that huge labyrinth of forums at all. As for the documentation, the website has a great deal of stuff, and whatever isn't there, just search the email archives (many such archives exist), and if that's a pain too, just drop a note to the pgsql list. You'll have an answer or excellent pointers more quickly than you imagine. I'm a recent convert to PgSQL (8.2.3) and while it took me a month to really figure things out and tune my database, I am simply amazed at the way things are structured, at the performance, and at the resilience/functionality offered by this stupendous db. (Having been a devout MySQL fan for over six years now). There's a reason a product creates passionate zealots.