Mischa, > Okay, although given the track record of page-based sampling for > n-distinct, it's a bit like looking for your keys under the streetlight, > rather than in the alley where you dropped them :-)
Bad analogy, but funny. The issue with page-based vs. pure random sampling is that to do, for example, 10% of rows purely randomly would actually mean loading 50% of pages. With 20% of rows, you might as well scan the whole table. Unless, of course, we use indexes for sampling, which seems like a *really good* idea to me .... -- --Josh Josh Berkus Aglio Database Solutions San Francisco ---------------------------(end of broadcast)--------------------------- TIP 5: Have you checked our extensive FAQ? http://www.postgresql.org/docs/faq