On Mon, Feb 22, 2010 at 8:18 AM, Gokulakannan Somasundaram
<gokul007@gmail.com> wrote:
> a) IOT has both table and index in one structure. So no duplication of data
> b) With visibility maps, we have three structures a) Table b) Index c)
> Visibility map. So the disk footprint of the same data will be higher in
> postgres ( 2x + size of the visibility map).
These sound like the same point to me. I don't think we're concerned
with footprint -- only with how much of that footprint actually needs
to be scanned. So if we have a solution allowing the scan to only need
to look at the index then the extra footprint of the table doesn't
cost anything at run-time. And the visibility map is very small.
I think you would be better off looking for incremental improvements
rather than major architectural changes like having no heap for a
table. There are so many design decisions hinged on having a heap that
it would be impractical to rethink them all.
--
greg