Re: Review: listagg aggregate

Pavel Stehule <pavel.stehule@gmail.com> writes:
> in 99.99% the second argument will be a constant. Can we use this
> information and optimize function for this case?

> The detoast on every row can take some percent from a performance.

What detoast?  There won't be one for a constant, nor even for a
variable in any sane situation --- who's going to be using
multi-kilobyte delimiter values?  And if they do, aren't they likely
to run out of memory for the result long before the repeated detoasts
become an interesting problem?  You're arguing about a case that
seems quite irrelevant to the real world.
        regards, tom lane