""John Top-k apad"" <topkapad@xxxxxxxxx> wrote > > from pg_stast_get_blocks_fetched i can see that both queries need almost the > same number of disk fetches which is quite reasonable ( the index is > unclustered). > > But as you can see there is a great variation between query > runtimes.Cansomeone explain this differnce? > Can you give a self-contained example (including what you did to clear the file system cache (maybe unmount?) to *not* let the 2nd query to use the file content from the 1st query)? Regards, Qingqing
