Re: Speed of user-defined aggregates using array_append as transfn

Andrew Dunstan <andrew@dunslane.net> writes:
> My initial admittedly ugly thought was why not have a second append 
> function that doesn't use expanded arrays?

That won't get us out of the O(N^2) behavior.  Also I don't see what's
better about it than my suggestion of making array_append itself do
that when called as an aggregate function.
        regards, tom lane