On 1/23/07, Heikki Linnakangas <[EMAIL PROTECTED]> wrote:
Pavan Deolasee wrote:
> So during a sequential or index scan, if a tuple is found to be dead,
> corresponding line pointer is marked "unused" and the space is returned
> to a
> free list. This free list is maintained within the page. A linked-list
> be used for this purpose and the special area of the heap-page can be
> to track the fragment list. We can maintain some additional information
> about the fragmented space such as, total_free_space, max_fragment_size,
> num_of_fragments etc in the special area.
Maintaining a list like that seems like a lot of hassle to me. Instead,
you could just scan the line pointers looking for a dead tuple of the
right size. We already have to scan the line pointers when inserting to
find a free line pointer.
That's a good suggestion. Just to avoid useless scans when there is no
fragment which can accommodate the new tuple, we may have some book keeping
information in the special area though.