Re: range remove in BTree, or other table storage

"paul c" <toledobythesea_at_oohay.ac> wrote in message news:PPLDh.1128282$R63.1101865_at_pd7urf1no...
> Marshall wrote:
> > On Feb 23, 12:54 pm, "Cimode" <cim..._at_hotmail.com> wrote:
> >
> >>On 23 fév, 19:54, "laurent" <laurento..._at_gmail.com> wrote:
> >>
> >>
> >>>Certainly reading books in an excellent method of education,
> >>>but I disagree that there is no educational value in using the
> >>>internet.
> >>
> >>Disagree with whom ?
> >
> >
> > With the guy who said "you will not get a serious database education
> > by using google or online questions". It was in the context of
> > my message but you snipped it.
> >
> >
> > Marshall
> >
>
> just to get back on the topic, first, i don't have references but could
> care less about them when talking to somebody who's programmed a btree
> but I would think when applied to some level in the "tree" the removal
> of a very definite range should be very fast provided that the free list
> "underneath" it, if you will, is also physically organized with the same
> kind of structure as the tree itself.
>
> as far as physical IO's are concerned, only the nodes at the highest
> levels would have to change.
>

Pruning the tree might be extremely fast, but garbage collecting the space no longer in use could be a lot slower.

Also, pruning the tree might be extremely fast, but if the btree is an index onto a table, deleting the table entries corresponding to the tree entries pruned might be very slow. Received on Fri Mar 02 2007 - 22:35:34 CET