Re: Brain dump: btree collapsing

On Wed, Feb 12, 2003 at 05:42:44PM -0500, Tom Lane wrote:
> I've been thinking hard for the last few days about how to do space
> reclamation in b-tree indexes, i.e., recycle pages that are in
> no-longer-useful portions of the tree structure.

Hi Tom,

I've seen your applied changes. It looks real nice; I could probably
have spent a year trying to do that. You addressed a couple of things
that only occurred to me some time after I left for vacation, and then
several that I never thought about.

Putting the freelist on FSM rather on the metapage still strikes me as
kind of strange; I remember you said the metapage was not enough space
for all the possible candidate pages, but the FSM is even more limited.
Oh well.

Two things I regret: one is being unable to see the changes as patches
the way you applied them, to get a sense of how the code evolved.
Unfortunately the interface to CVS via web does not allow me to see it,
or I don't know how to use it. It's not that important, however,
because I was already somewhat familiar with the code.

The other is that now I am left without a graduate project :-( I will
continue looking at the TODO list for something that's of an appropiate
size for me. (Professors here don't have any but the slightest idea of
Postgres, so they aren't of any help.) I'm still thinking on
implementing a replacement for the regex engine based on the Shift-or
algorithm, if only to have a speed comparison with traditional engines.

--
Alvaro Herrera (<alvherre[a]dcc.uchile.cl>)
"Doing what he did amounts to sticking his fingers under the hood of the
implementation; if he gets his fingers burnt, it's his problem." (Tom Lane)