Benchmark

Is there anywhere I can find some benchmark test for postgres. The reason is that I want to use it for a site that
couldhave several simultanous users querying the database and I want to be sure that it is stable (and fast) enough to
handlethat kind of (ab)use.
 

Also which is fastest ?

1. A query (using index of course) for a text in the database.

or 

2. Reading from a file on the harddisk.


If the answer is 1 will the answer still be 1 if I do it several times (100.000+ a day)


Regards Nikolaj