Re: Problem with index in OR'd expression

On mið, 2006-12-27 at 11:02 -0600, postgresql(dot)org(at)tgice(dot)com wrote:
>
> I was referring to the situation where one has this in a WHERE clause:
>
> ((vConstant IS NULL) OR (Table.IndexedCol = vConstant))
>
> where vConstant is a *constant* parameter in a pl/pgsql function.

Reguardless of the issue whether pl/pgsql could be expected to
optimize this case, I find it difficult to imagine a scenario
where this kind of coding makes sense.

I understand that in some cases on would like to do this with
a *variable* to simplify logic, but what possible gain can
be had from doing this with a constant, other that obfuscation?

It does not make sense to spend CPU-time on optimizing a case
that is not useful or common.

gnari