Josh Berkus <josh@agliodbs.com> writes: >> So what's going on with the empirically derived value of 4?
> It's not empirically derived; Yes it is. I ran experiments back in the late 90s to derive it. Check the archives. Disks have gotten noticeably bigger since then, but I don't think the ratio of seek time to rotation rate has changed much. regards, tom lane ---------------------------(end of broadcast)--------------------------- TIP 7: don't forget to increase your free space map settings