Re: Perfomance of views

Svenne Krap <svenne@krap.dk> writes:
> The ways I have considered was :
> 1) write a big query in hand (not preferred as it gets hard to manage)
> 2) write layers of views (still not prefered as I still have to remember
> to put on the right conditions everywhere)
> 3) write layers of sql-functions (returning the right sets of rows from
> the underlying tables) - which I prefer from a development angel .. it
> gets very clean and I cant forget a parameter anywhere.

#1 and #2 should behave pretty similarly, assuming that the "one big
query" would have been structured the same way as the nest of views is.
#3 unfortunately will pretty much suck, because there's no chance for
cross-level optimization.

There's been some discussion of inline-expanding SQL functions that
return sets when they are called in FROM, which would make a SQL
function that contains just a SELECT effectively equivalent to a view
as far as the planner's powers of optimization go.  No one's tried to
make it happen yet though.

            regards, tom lane