> > attribute_list is an array of composite type (with 20 fields).
I am trying to wrap my head around "array of composite type". Please provide an example.
ARRAY[ (1,2)::point, (3,4)::point ]::point[]
The main problem is the concept of writing "from($1)" in any query makes no sense, you cannot parameterize a from clause directly like that. You have to put the value somewhere an expression is directly allowed.