> Obviously indexed joins on a single database server scale just fine, that's the entire selling point of an RDMBS! Is it really obvious, though? In my experi

> Obviously indexed joins on a single database server scale just fine, that's the entire selling point of an RDMBS! Is it really obvious, though? In my experience, many people consistently fail to grasp this point. It seems likely that the underlying reason is that it's easy for most people to conflate nested loop join with hash join (or with merge join). Hash join really doesn't scale in the sense that the author conveys (though this in itself many not matter, because they're not really in competition in any practical sense). When you point out that the key to good performance is to ensure that query results are fetched rather than searched and computed, it sounds obvious. It still seems very helpful to connect the dots.