Greg Stark <stark@mit.edu> writes:
> On Sun, Oct 9, 2011 at 9:03 PM, Tom Lane <tgl@sss.pgh.pa.us> wrote:
>> At the moment I'm leaning to approach #3, but I wonder if anyone has
>> a different opinion or another idea altogether.
> Would any of these make it more realistic to talk about the crazy
> plans Heikki suggested like doing two index scans, doing the join
> between the index tuples, and only then looking up the visibility
> information and remaining columns for the tuple on the matching rows?
I don't think it's particularly relevant --- we would not want to use
weird representations of the Vars outside the index scan nodes. Above
the scan they'd be just like any other upper-level Vars.
(FWIW, that idea isn't crazy; I remember having discussions of it back
in 2003 or so.)
regards, tom lane