Have you thought of trying Amazon's simpledb? I just to my beta login and it seems pretty awesome so far.
what about couchdb? Still young but can be clustered and will probably way outperform any relational db for the stuff you're describing.
Last time I did benchmarks (a few years ago) mssql totally blew away mysql and postgres on windows. Turns out this was b/c I was using a "dependent subquery" which in my opinion is a lot simpler way to write a lot of queries.
Now that I use mysql (and linux and solaris) exclusively I don't use dependent subqueries at all and all is well.
what about couchdb? Still young but can be clustered and will probably way outperform any relational db for the stuff you're describing.
Last time I did benchmarks (a few years ago) mssql totally blew away mysql and postgres on windows. Turns out this was b/c I was using a "dependent subquery" which in my opinion is a lot simpler way to write a lot of queries.
Now that I use mysql (and linux and solaris) exclusively I don't use dependent subqueries at all and all is well.