Re: Another idea for index-only scans - Mailing list pgsql-hackers

Alvaro Herrera <alvherre@commandprompt.com> writes:
>> On Wed, 2007-08-15 at 11:54 -0400, Bruce Momjian wrote:
>>> A third idea would be for a heap scan to check if all rows are visible
>>> and if so set a per-table flag which can be checked by index scans.

> I think it's too coarse-grained to be really useful.  If it was one bit
> per page it could work, but one bit per relation is going to be reset
> too frequently.

Another problem it would have is that the flag would be a single point
of contention.
        regards, tom lane