Re: final patch - plpgsql: for-in-array

2010/11/18 Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us>:
> Merlin Moncure <mmoncure(at)gmail(dot)com> writes:
>> On Thu, Nov 18, 2010 at 12:47 AM, Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us> wrote:
>>> Yes, which begs the question of why bother at all.
>
>> Pavel's performance argument is imnsho valid.
>
> Well, that argument is unsupported by any evidence, so far as I've seen.
>
> More to the point, if there is indeed an interesting performance win
> here, we could get the same win by internally optimizing the existing
> syntax.  That would provide the benefit to existing code not just
> new code; and it would avoid foreclosing our future options for
> extending FOR in not-so-redundant ways.

sorry, but I don't agree. I don't think, so there are some big space
for optimizing - and if then it means much more code complexity for
current expr executor. Next - FOR IN ARRAY takes fields from array on
request - and it is possible, because a unpacking of array is
controlled by statement - it's impossible do same when unpacking is
inside other functions with same effectivity.

Regards

Pavel Stehule

>
>                        regards, tom lane
>