Hi,
I think in this page should mention partitioning (5.9) in the very first paragraph. Or some way hint the reader that might be the actual thing they're after.
Years ago I was learning about splitting tables into smaller pieces and I found this inheritance manual page but it didn't make any sense because it talks about cities and capitals and there aren't that many of them. So why I would need this? Then I asked about inheritance usage in a forum and I got statistics and logs as examples. This changed my mind to thinking about tables splitted into years and months and multi-million lines of data instead of some hundreds (that cities and states example). Only then I found what I was actually looking for, partitioning.
Partitioning manual page is very good because measurements is used as example. This gets the reader/developer into the "lots of data" mindset which starts questioning performance.