Re: Block B-Tree concept

Heikki Linnakangas wrote:
> Tom Lane wrote:
> > Heikki Linnakangas <heikki(at)enterprisedb(dot)com> writes:
> >
> >> I've been experimenting with the idea of a so-called Block B-Tree. The
> >> basic idea is that instead of storing an index tuple for each heap
> >> tuple, we store an index tuple for each heap block. This dramatically
> >> reduces the size of an index, leading to savings on I/O.
> >>
> >
> > VACUUM?
> >
> There's a few options that I've thought of this far:
>
> 1. Whenever a tuple is found dead on page X, vacuum of the index will
> have to go to that page again to see if there's any matching tuples left.

Right now, if an index entry points to a dead tuple, we set a bit in
the index so future lookups do not access the heap. We could set a bit
for block index entries that point to a page that has no live rows, and
have vacuum remove the index entry later.

--
Bruce Momjian bruce(at)momjian(dot)us
EnterpriseDB http://www.enterprisedb.com

+ If your life is a hard drive, Christ can be your backup. +