Re: [HACKERS] Couple of issues with prepared FETCH commands

>>>>> "Robert" == Robert Haas <robertmhaas@gmail.com> writes:
>> But the problem that actually came up is this: if you do the>> PQprepare before the named cursor has actually been
opened,then>> everything works _up until_ the first event, such as a change to>> search_path, that forces a
revalidation;and at that point it fails>> with the "must not change result type" error _even if_ the cursor>> always
hasexactly the same result type.  This happens because the>> initial prepare actually stored NULL for
plansource->resultDesc,>>since the cursor name wasn't found, while on the revalidate, when>> the cursor obviously does
exist,it gets the actual result type.>> >> It seems a bit of a "gotcha" to have it fail in this case when the>> result
typeisn't actually being checked in other cases.
 
Robert> To me, that sounds like a bug.

So what's the appropriate fix? My suggestion would be to suppress the
result type check entirely for utility statements; EXPLAIN and SHOW
always return the same thing anyway, and both FETCH and EXECUTE are
subject to the issue described. This would mean conceding that the
result descriptor of a prepared FETCH or EXECUTE might change (i.e. a
Describe of the statement might not be useful, though a Describe of an
opened portal would be ok). I think this would result in the most
obviously correct behavior from the client point of view.

-- 
Andrew (irc:RhodiumToad)