> For example, if you have a timestamp index and you routinely clean out
> all entries older than N-days-ago, you won't have a problem in 7.4.
> If your pattern is to delete nine out of every ten entries (maybe you
> drop minute-by-minute entries and keep only hourly entries after awhile)
> then you might find the index loading getting unpleasantly low. We'll
> have to see whether it's a problem in practice. I'm willing to revisit
> the page-merging problem if it's proven to be a real practical problem,
> but it looked hard enough that I think it's more profitable to spend the
> development effort elsewhere until it's proven necessary.
A pattern I have on a few tables is to record daily data. After a
period of time, create an entry for a week that is the sums of 7 days,
after another period of time compress 4 weeks into a month.
Index is on the date representing the block. It's a new insert, but
would go onto the old page. Anyway, I don't have that much data (~20M
rows) -- but I believe it is a real-world example of this pattern.