Greg Stark escribió: > On Mon, Feb 22, 2010 at 8:18 AM, Gokulakannan Somasundaram > <gokul...@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.
Moreover, the visibility map is already there. -- Alvaro Herrera http://www.CommandPrompt.com/ PostgreSQL Replication, Consulting, Custom Development, 24x7 support -- Sent via pgsql-hackers mailing list (pgsql-hackers@postgresql.org) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-hackers
