Re: explain and PARAM_EXEC

Robert Haas <robertmhaas@gmail.com> writes:
> On Fri, Feb 19, 2010 at 11:33 PM, Tom Lane <tgl@sss.pgh.pa.us> wrote:
>> We can also fetch that tuple's
>> relfilenode and pass it to the subplan, which we do by setting the $0
>> Param value before invoking the subplan.

> Are the same tuples in scope when evaluating the expression that sets
> $0 as were in scope when evaluating  ((b.oid)::integer + 1)?

Yes, exactly the same.  The parameter-value expression is just like any
other scalar expression that could appear where the SubPlan reference
is.  It doesn't know anything about the subplan, really.
        regards, tom lane