True - that&#x27;s what I had to battle with as well - disk seek cost vs. read speeds - Postgres does collect stats on that IIRC (in special tables), but might still need to advise it on that. And do lots of EXPLAIN ANALYZE (incl. BUFFERS sometimes) to check what happens. Re. buffers etc., I also had this nagging idea that the way Postgres sorts sets sometimes takes into account cache misses (i.e. it may use sort algo which compares elements that are not that far away - but not sure on this - also, perhaps this is to be expected anyway).