Re: Free Space Map data structure

"Heikki Linnakangas" <heikki@enterprisedb.com> writes:

> For example:
>
>     9
>  4     9
> 2 4   0 9

It occurs to me now that this it actually wouldn't be so easy to ripple up
changes due to the amount amount of space *decreasing*. Consider if you reduce
the leaf 9 to an 8. You want to decrease its parent to 8 but first you have to
check that its sibling isn't also 9. Again when you get to the grandparnt you
have to check that the "4" isn't a 9. As long as you're on one page that's
cheap but if it means paging in another page of the FSM that could be
annoying.

--  Gregory Stark EnterpriseDB          http://www.enterprisedb.com Ask me about EnterpriseDB's PostGIS support!