Re: BUG #9227: Error on SELECT ROW OVERLAPS ROW with single ROW argument

Joshua Yanovski <pythonesque(at)gmail(dot)com> writes:
> On Mon, Feb 17, 2014 at 4:33 PM, Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us> wrote:
>> While it would be a reasonably simple change to make this work as
>> originally intended, I'm strongly tempted to just rip it out instead,
>> and only support the SQL-mandated syntax. If anyone was using this
>> undocumented feature, you'd think they'd have complained sometime in
>> the last ten years. And making it work would really entail adding
>> documentation and a regression test case, so it'd be substantially
>> more effort than just killing the "list_length == 1" case.

> Attaching a patch to just remove the n == 1 case.

It occurred to me that there's an additional reason not to make the
code work like Lockhart seems to have envisioned: if it did duplicate
the argument like that, that'd lead to double evaluation of any volatile
function that's present in the argument. So I've gone ahead and committed
this, along with some further fooling around to make the error messages
nicer.

regards, tom lane